WorldWideScience

Sample records for confidence interval tests

  1. Sample Size for the "Z" Test and Its Confidence Interval

    Science.gov (United States)

    Liu, Xiaofeng Steven

    2012-01-01

    The statistical power of a significance test is closely related to the length of the confidence interval (i.e. estimate precision). In the case of a "Z" test, the length of the confidence interval can be expressed as a function of the statistical power. (Contains 1 figure and 1 table.)

  2. Using Confidence Intervals for Assessing Reliability of Real Tests.

    Science.gov (United States)

    Oosterwijk, Pieter R; van der Ark, L Andries; Sijtsma, Klaas

    2017-10-01

    Test authors report sample reliability values but rarely consider the sampling error and related confidence intervals. This study investigated the truth of this conjecture for 116 tests with 1,024 reliability estimates (105 pertaining to test batteries and 919 to tests measuring a single attribute) obtained from an online database. Based on 90% confidence intervals, approximately 20% of the initial quality assessments had to be downgraded. For 95% confidence intervals, the percentage was approximately 23%. The results demonstrated that reported reliability values cannot be trusted without considering their estimation precision.

  3. Confidence Intervals: From tests of statistical significance to confidence intervals, range hypotheses and substantial effects

    Directory of Open Access Journals (Sweden)

    Dominic Beaulieu-Prévost

    2006-03-01

    Full Text Available For the last 50 years of research in quantitative social sciences, the empirical evaluation of scientific hypotheses has been based on the rejection or not of the null hypothesis. However, more than 300 articles demonstrated that this method was problematic. In summary, null hypothesis testing (NHT is unfalsifiable, its results depend directly on sample size and the null hypothesis is both improbable and not plausible. Consequently, alternatives to NHT such as confidence intervals (CI and measures of effect size are starting to be used in scientific publications. The purpose of this article is, first, to provide the conceptual tools necessary to implement an approach based on confidence intervals, and second, to briefly demonstrate why such an approach is an interesting alternative to an approach based on NHT. As demonstrated in the article, the proposed CI approach avoids most problems related to a NHT approach and can often improve the scientific and contextual relevance of the statistical interpretations by testing range hypotheses instead of a point hypothesis and by defining the minimal value of a substantial effect. The main advantage of such a CI approach is that it replaces the notion of statistical power by an easily interpretable three-value logic (probable presence of a substantial effect, probable absence of a substantial effect and probabilistic undetermination. The demonstration includes a complete example.

  4. Using confidence intervals for assessing reliability of real tests

    NARCIS (Netherlands)

    Oosterwijk, P.R.; van der Ark, L.A.; Sijtsma, K.

    2018-01-01

    Test authors report sample reliability values but rarely consider the sampling error and related confidence intervals. This study investigated the truth of this conjecture for 116 tests with 1,024 reliability estimates (105 pertaining to test batteries and 919 to tests measuring a single attribute)

  5. Parametric change point estimation, testing and confidence interval ...

    African Journals Online (AJOL)

    In many applications like finance, industry and medicine, it is important to consider that the model parameters may undergo changes at unknown moment in time. This paper deals with estimation, testing and confidence interval of a change point for a univariate variable which is assumed to be normally distributed. To detect ...

  6. Confidence Intervals for Laboratory Sonic Boom Annoyance Tests

    Science.gov (United States)

    Rathsam, Jonathan; Christian, Andrew

    2016-01-01

    Commercial supersonic flight is currently forbidden over land because sonic booms have historically caused unacceptable annoyance levels in overflown communities. NASA is providing data and expertise to noise regulators as they consider relaxing the ban for future quiet supersonic aircraft. One deliverable NASA will provide is a predictive model for indoor annoyance to aid in setting an acceptable quiet sonic boom threshold. A laboratory study was conducted to determine how indoor vibrations caused by sonic booms affect annoyance judgments. The test method required finding the point of subjective equality (PSE) between sonic boom signals that cause vibrations and signals not causing vibrations played at various amplitudes. This presentation focuses on a few statistical techniques for estimating the interval around the PSE. The techniques examined are the Delta Method, Parametric and Nonparametric Bootstrapping, and Bayesian Posterior Estimation.

  7. Confidence intervals for test information and relative efficiency

    NARCIS (Netherlands)

    Oosterloo, Sebe J.

    1984-01-01

    In latent theory the measurement properties of a mental test can be expressed in the test information function. The relative merits of two tests for the same latent trait can be described by the relative efficiency function, i.e. the ratio of the test information functions. It is argued that these

  8. Tests and Confidence Intervals for an Extended Variance Component Using the Modified Likelihood Ratio Statistic

    DEFF Research Database (Denmark)

    Christensen, Ole Fredslund; Frydenberg, Morten; Jensen, Jens Ledet

    2005-01-01

    The large deviation modified likelihood ratio statistic is studied for testing a variance component equal to a specified value. Formulas are presented in the general balanced case, whereas in the unbalanced case only the one-way random effects model is studied. Simulation studies are presented, s......, showing that the normal approximation to the large deviation modified likelihood ratio statistic gives confidence intervals for variance components with coverage probabilities very close to the nominal confidence coefficient....

  9. Assessing Conformance with Benford's Law: Goodness-Of-Fit Tests and Simultaneous Confidence Intervals.

    Directory of Open Access Journals (Sweden)

    M Lesperance

    Full Text Available Benford's Law is a probability distribution for the first significant digits of numbers, for example, the first significant digits of the numbers 871 and 0.22 are 8 and 2 respectively. The law is particularly remarkable because many types of data are considered to be consistent with Benford's Law and scientists and investigators have applied it in diverse areas, for example, diagnostic tests for mathematical models in Biology, Genomics, Neuroscience, image analysis and fraud detection. In this article we present and compare statistically sound methods for assessing conformance of data with Benford's Law, including discrete versions of Cramér-von Mises (CvM statistical tests and simultaneous confidence intervals. We demonstrate that the common use of many binomial confidence intervals leads to rejection of Benford too often for truly Benford data. Based on our investigation, we recommend that the CvM statistic Ud(2, Pearson's chi-square statistic and 100(1 - α% Goodman's simultaneous confidence intervals be computed when assessing conformance with Benford's Law. Visual inspection of the data with simultaneous confidence intervals is useful for understanding departures from Benford and the influence of sample size.

  10. Robust misinterpretation of confidence intervals

    NARCIS (Netherlands)

    Hoekstra, R.; Morey, R.D.; Rouder, J.N.; Wagenmakers, E.-J.

    2014-01-01

    Null hypothesis significance testing (NHST) is undoubtedly the most common inferential technique used to justify claims in the social sciences. However, even staunch defenders of NHST agree that its outcomes are often misinterpreted. Confidence intervals (CIs) have frequently been proposed as a more

  11. Test Statistics and Confidence Intervals to Establish Noninferiority between Treatments with Ordinal Categorical Data.

    Science.gov (United States)

    Zhang, Fanghong; Miyaoka, Etsuo; Huang, Fuping; Tanaka, Yutaka

    2015-01-01

    The problem for establishing noninferiority is discussed between a new treatment and a standard (control) treatment with ordinal categorical data. A measure of treatment effect is used and a method of specifying noninferiority margin for the measure is provided. Two Z-type test statistics are proposed where the estimation of variance is constructed under the shifted null hypothesis using U-statistics. Furthermore, the confidence interval and the sample size formula are given based on the proposed test statistics. The proposed procedure is applied to a dataset from a clinical trial. A simulation study is conducted to compare the performance of the proposed test statistics with that of the existing ones, and the results show that the proposed test statistics are better in terms of the deviation from nominal level and the power.

  12. Statistical tests, P values, confidence intervals, and power: a guide to misinterpretations.

    Science.gov (United States)

    Greenland, Sander; Senn, Stephen J; Rothman, Kenneth J; Carlin, John B; Poole, Charles; Goodman, Steven N; Altman, Douglas G

    2016-04-01

    Misinterpretation and abuse of statistical tests, confidence intervals, and statistical power have been decried for decades, yet remain rampant. A key problem is that there are no interpretations of these concepts that are at once simple, intuitive, correct, and foolproof. Instead, correct use and interpretation of these statistics requires an attention to detail which seems to tax the patience of working scientists. This high cognitive demand has led to an epidemic of shortcut definitions and interpretations that are simply wrong, sometimes disastrously so-and yet these misinterpretations dominate much of the scientific literature. In light of this problem, we provide definitions and a discussion of basic statistics that are more general and critical than typically found in traditional introductory expositions. Our goal is to provide a resource for instructors, researchers, and consumers of statistics whose knowledge of statistical theory and technique may be limited but who wish to avoid and spot misinterpretations. We emphasize how violation of often unstated analysis protocols (such as selecting analyses for presentation based on the P values they produce) can lead to small P values even if the declared test hypothesis is correct, and can lead to large P values even if that hypothesis is incorrect. We then provide an explanatory list of 25 misinterpretations of P values, confidence intervals, and power. We conclude with guidelines for improving statistical interpretation and reporting.

  13. Standard Errors and Confidence Intervals of Norm Statistics for Educational and Psychological Tests.

    Science.gov (United States)

    Oosterhuis, Hannah E M; van der Ark, L Andries; Sijtsma, Klaas

    2016-11-14

    Norm statistics allow for the interpretation of scores on psychological and educational tests, by relating the test score of an individual test taker to the test scores of individuals belonging to the same gender, age, or education groups, et cetera. Given the uncertainty due to sampling error, one would expect researchers to report standard errors for norm statistics. In practice, standard errors are seldom reported; they are either unavailable or derived under strong distributional assumptions that may not be realistic for test scores. We derived standard errors for four norm statistics (standard deviation, percentile ranks, stanine boundaries and Z-scores) under the mild assumption that the test scores are multinomially distributed. A simulation study showed that the standard errors were unbiased and that corresponding Wald-based confidence intervals had good coverage. Finally, we discuss the possibilities for applying the standard errors in practical test use in education and psychology. The procedure is provided via the R function check.norms, which is available in the mokken package.

  14. Test-compatible confidence intervals for adaptive two-stage single-arm designs with binary endpoint.

    Science.gov (United States)

    Kunzmann, Kevin; Kieser, Meinhard

    2017-10-27

    Inference after two-stage single-arm designs with binary endpoint is challenging due to the nonunique ordering of the sampling space in multistage designs. We illustrate the problem of specifying test-compatible confidence intervals for designs with nonconstant second-stage sample size and present two approaches that guarantee confidence intervals consistent with the test decision. Firstly, we extend the well-known Clopper-Pearson approach of inverting a family of two-sided hypothesis tests from the group-sequential case to designs with fully adaptive sample size. Test compatibility is achieved by using a sample space ordering that is derived from a test-compatible estimator. The resulting confidence intervals tend to be conservative but assure the nominal coverage probability. In order to assess the possibility of further improving these confidence intervals, we pursue a direct optimization approach minimizing the mean width of the confidence intervals. While the latter approach produces more stable coverage probabilities, it is also slightly anti-conservative and yields only negligible improvements in mean width. We conclude that the Clopper-Pearson-type confidence intervals based on a test-compatible estimator are the best choice if the nominal coverage probability is not to be undershot and compatibility of test decision and confidence interval is to be preserved. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Confidence intervals permit, but don't guarantee, better inference than statistical significance testing

    Directory of Open Access Journals (Sweden)

    Melissa Coulson

    2010-07-01

    Full Text Available A statistically significant result, and a non-significant result may differ little, although significance status may tempt an interpretation of difference. Two studies are reported that compared interpretation of such results presented using null hypothesis significance testing (NHST, or confidence intervals (CIs. Authors of articles published in psychology, behavioural neuroscience, and medical journals were asked, via email, to interpret two fictitious studies that found similar results, one statistically significant, and the other non-significant. Responses from 330 authors varied greatly, but interpretation was generally poor, whether results were presented as CIs or using NHST. However, when interpreting CIs respondents who mentioned NHST were 60% likely to conclude, unjustifiably, the two results conflicted, whereas those who interpreted CIs without reference to NHST were 95% likely to conclude, justifiably, the two results were consistent. Findings were generally similar for all three disciplines. An email survey of academic psychologists confirmed that CIs elicit better interpretations if NHST is not invoked. Improved statistical inference can result from encouragement of meta-analytic thinking and use of CIs but, for full benefit, such highly desirable statistical reform requires also that researchers interpret CIs without recourse to NHST.

  16. Nonparametric confidence intervals for monotone functions

    NARCIS (Netherlands)

    Groeneboom, P.; Jongbloed, G.

    2015-01-01

    We study nonparametric isotonic confidence intervals for monotone functions. In [Ann. Statist. 29 (2001) 1699–1731], pointwise confidence intervals, based on likelihood ratio tests using the restricted and unrestricted MLE in the current status model, are introduced. We extend the method to the

  17. Robust misinterpretation of confidence intervals.

    Science.gov (United States)

    Hoekstra, Rink; Morey, Richard D; Rouder, Jeffrey N; Wagenmakers, Eric-Jan

    2014-10-01

    Null hypothesis significance testing (NHST) is undoubtedly the most common inferential technique used to justify claims in the social sciences. However, even staunch defenders of NHST agree that its outcomes are often misinterpreted. Confidence intervals (CIs) have frequently been proposed as a more useful alternative to NHST, and their use is strongly encouraged in the APA Manual. Nevertheless, little is known about how researchers interpret CIs. In this study, 120 researchers and 442 students-all in the field of psychology-were asked to assess the truth value of six particular statements involving different interpretations of a CI. Although all six statements were false, both researchers and students endorsed, on average, more than three statements, indicating a gross misunderstanding of CIs. Self-declared experience with statistics was not related to researchers' performance, and, even more surprisingly, researchers hardly outperformed the students, even though the students had not received any education on statistical inference whatsoever. Our findings suggest that many researchers do not know the correct interpretation of a CI. The misunderstandings surrounding p-values and CIs are particularly unfortunate because they constitute the main tools by which psychologists draw conclusions from data.

  18. Population Validity and Cross-Validity: Applications of Distribution Theory for Testing Hypotheses, Setting Confidence Intervals, and Determining Sample Size

    Science.gov (United States)

    Algina, James; Keselman, H. J.

    2008-01-01

    Applications of distribution theory for the squared multiple correlation coefficient and the squared cross-validation coefficient are reviewed, and computer programs for these applications are made available. The applications include confidence intervals, hypothesis testing, and sample size selection. (Contains 2 tables.)

  19. Statistics with confidence confidence intervals and statistical guidelines

    CERN Document Server

    Altman, Douglas; Bryant, Trevor; Gardner, Stephen

    2013-01-01

    This highly popular introduction to confidence intervals has been thoroughly updated and expanded. It includes methods for using confidence intervals, with illustrative worked examples and extensive guidelines and checklists to help the novice.

  20. Confidence Intervals for Cronbach's Coefficient Alpha Values

    OpenAIRE

    Koning, Alex; Franses, Philip Hans

    2003-01-01

    textabstractCoefficient Alpha, which is widely used in empirical research, estimates the reliability of a test consisting of parallel items. In practice it is difficult to compare values of alpha across studies as it depends on the number of items used. In this paper we provide a simple solution, which amounts to computing the confidence intervals of an alpha, as these intervals automatically account for differences across the numbers of items. We also give appropriate statistics to test for ...

  1. The fallacy of placing confidence in confidence intervals

    NARCIS (Netherlands)

    Morey, R.D.; Hoekstra, R.; Rouder, J.N.; Lee, M.D.; Wagenmakers, E.-J.

    Interval estimates – estimates of parameters that include an allowance for sampling uncertainty – have long been touted as a key component of statistical analyses. There are several kinds of interval estimates, but the most popular are confidence intervals (CIs): intervals that contain the true

  2. The fallacy of placing confidence in confidence intervals

    NARCIS (Netherlands)

    Morey, Richard D.; Hoekstra, Rink; Rouder, Jeffrey N.; Lee, Michael D.; Wagenmakers, Eric-Jan

    2016-01-01

    Interval estimates – estimates of parameters that include an allowance for sampling uncertainty – have long been touted as a key component of statistical analyses. There are several kinds of interval estimates, but the most popular are confidence intervals (CIs): intervals that contain the true

  3. Confidence Intervals from One One Observation

    CERN Document Server

    Rodriguez, Carlos C

    2008-01-01

    Robert Machol's surprising result, that from a single observation it is possible to have finite length confidence intervals for the parameters of location-scale models, is re-produced and extended. Two previously unpublished modifications are included. First, Herbert Robbins nonparametric confidence interval is obtained. Second, I introduce a technique for obtaining confidence intervals for the scale parameter of finite length in the logarithmic metric. Keywords: Theory/Foundations , Estimation, Prior Distributions, Non-parametrics & Semi-parametrics Geometry of Inference, Confidence Intervals, Location-Scale models

  4. Contrasting Diversity Values: Statistical Inferences Based on Overlapping Confidence Intervals

    Science.gov (United States)

    MacGregor-Fors, Ian; Payton, Mark E.

    2013-01-01

    Ecologists often contrast diversity (species richness and abundances) using tests for comparing means or indices. However, many popular software applications do not support performing standard inferential statistics for estimates of species richness and/or density. In this study we simulated the behavior of asymmetric log-normal confidence intervals and determined an interval level that mimics statistical tests with P(α) = 0.05 when confidence intervals from two distributions do not overlap. Our results show that 84% confidence intervals robustly mimic 0.05 statistical tests for asymmetric confidence intervals, as has been demonstrated for symmetric ones in the past. Finally, we provide detailed user-guides for calculating 84% confidence intervals in two of the most robust and highly-used freeware related to diversity measurements for wildlife (i.e., EstimateS, Distance). PMID:23437239

  5. Fusing photovoltaic data for improved confidence intervals

    Directory of Open Access Journals (Sweden)

    Ansgar Steland

    2017-01-01

    Full Text Available Characterizing and testing photovoltaic modules requires carefully made measurements on important variables such as the power output under standard conditions. When additional data is available, which has been collected using a different measurement system and therefore may be of different accuracy, the question arises how one can combine the information present in both data sets. In some cases one even has prior knowledge about the ordering of the variances of the measurement errors, which is not fully taken into account by commonly known estimators. We discuss several statistical estimators to combine the sample means of independent series of measurements, both under the assumption of heterogeneous variances and ordered variances. The critical issue is then to assess the estimator’s variance and to construct confidence intervals. We propose and discuss the application of a new jackknife variance estimator devised by [1] to such photovoltaic data, in order to assess the variability of common mean estimation under heterogeneous and ordered variances in a reliable and nonparametric way. When serial correlations are present, which usually a ect the marginal variances, it is proposed to construct a thinned data set by downsampling the series in such a way that autocorrelations are removed or dampened. We propose a data adaptive procedure which downsamples a series at irregularly spaced time points in such a way that the autocorrelations are minimized. The procedures are illustrated by applying them to real photovoltaic power output measurements from two different sun light flashers. In addition, focusing on simulations governed by real photovoltaic data, we investigate the accuracy of the jackknife approach and compare it with other approaches. Among those is a variance estimator based on Nair’s formula for Gaussian data and, as a parametric alternative, two Bayesian models. We investigate the statistical accuracy of the resulting confidence

  6. Coefficient Omega Bootstrap Confidence Intervals: Nonnormal Distributions

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin

    2013-01-01

    The performance of the normal theory bootstrap (NTB), the percentile bootstrap (PB), and the bias-corrected and accelerated (BCa) bootstrap confidence intervals (CIs) for coefficient omega was assessed through a Monte Carlo simulation under conditions not previously investigated. Of particular interests were nonnormal Likert-type and binary items.…

  7. Confidence Intervals for Standardized Effect Sizes: Theory, Application, and Implementation

    Directory of Open Access Journals (Sweden)

    Ken Kelley

    2007-02-01

    Full Text Available The behavioral, educational, and social sciences are undergoing a paradigmatic shift in methodology, from disciplines that focus on the dichotomous outcome of null hypothesis significance tests to disciplines that report and interpret effect sizes and their corresponding confidence intervals. Due to the arbitrariness of many measurement instruments used in the behavioral, educational, and social sciences, some of the most widely reported effect sizes are standardized. Although forming confidence intervals for standardized effect sizes can be very beneficial, such confidence interval procedures are generally difficult to implement because they depend on noncentral t, F, and x2 distributions. At present, no main-stream statistical package provides exact confidence intervals for standardized effects without the use of specialized programming scripts. Methods for the Behavioral, Educational, and Social Sciences (MBESS is an R package that has routines for calculating confidence intervals for noncentral t, F, and x2 distributions, which are then used in the calculation of exact confidence intervals for standardized effect sizes by using the confidence interval transformation and inversion principles. The present article discusses the way in which confidence intervals are formed for standardized effect sizes and illustrates how such confidence intervals can be easily formed using MBESS in R.

  8. Confidence intervals for annual wind power production******

    Directory of Open Access Journals (Sweden)

    Bensoussan Alain

    2014-01-01

    Full Text Available Wind power is an intermittent resource due to wind speed intermittency. However wind speed can be described as a stochastic process with short memory. This allows us to derive a central limit theorem for the annual or pluri-annual wind power production and then get quantiles of the wind power production for one, ten or twenty years future periods. On the one hand, the interquantile spread offers a measurement of the intrinsic uncertainties of wind power production. On the other hand, different quantiles with different periods of time are used by financial institutions to quantify the financial risk of the wind turbine. Our method is then applied to real datasets corresponding to a French wind turbine. Since confidence intervals can be enhanced by taking into account seasonality, we present some tools for change point analysis on wind series.

  9. Exact confidence intervals for channelized Hotelling observer performance

    Science.gov (United States)

    Wunderlich, Adam; Noo, Frederic; Heilbrun, Marta

    2013-03-01

    Task-based assessments of image quality constitute a rigorous, principled approach to the evaluation of imaging system performance. To conduct such assessments, it has been recognized that mathematical model observers are very useful, particularly for purposes of imaging system development and optimization. One type of model observer that has been widely applied in the medical imaging community is the channelized Hotelling observer (CHO). In the present work, we address the need for reliable confidence interval estimators of CHO performance. Specifically, we observe that a procedure proposed by Reiser for interval estimation of the Mahalanobis distance can be applied to obtain confidence intervals for CHO performance. In addition, we find that these intervals are well-defined with theoretically-exact coverage probabilities, which is a new result not proved by Reiser. The confidence intervals are tested with Monte Carlo simulation and demonstrated with an example comparing x-ray CT reconstruction strategies.

  10. Hypothesis Testing, "p" Values, Confidence Intervals, Measures of Effect Size, and Bayesian Methods in Light of Modern Robust Techniques

    Science.gov (United States)

    Wilcox, Rand R.; Serang, Sarfaraz

    2017-01-01

    The article provides perspectives on p values, null hypothesis testing, and alternative techniques in light of modern robust statistical methods. Null hypothesis testing and "p" values can provide useful information provided they are interpreted in a sound manner, which includes taking into account insights and advances that have…

  11. Confidence Intervals from Normalized Data: A correction to Cousineau (2005

    Directory of Open Access Journals (Sweden)

    Richard D. Morey

    2008-09-01

    Full Text Available Presenting confidence intervals around means is a common method of expressing uncertainty in data. Loftus and Masson (1994 describe confidence intervals for means in within-subjects designs. These confidence intervals are based on the ANOVA mean squared error. Cousineau (2005 presents an alternative to the Loftus and Masson method, but his method produces confidence intervals that are smaller than those of Loftus and Masson. I show why this is the case and offer a simple correction that makes the expected size of Cousineau confidence intervals the same as that of Loftus and Masson confidence intervals.

  12. Learning about confidence intervals with software R

    Directory of Open Access Journals (Sweden)

    Gariela Gonçalves

    2013-08-01

    Full Text Available 0 0 1 202 1111 USAL 9 2 1311 14.0 Normal 0 21 false false false ES JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:ES; mso-fareast-language:EN-US;} This work was to study the feasibility of implementing a teaching method that employs software, in a Computational Mathematics course, involving students and teachers through the use of the statistical software R in carrying out practical work, such as strengthening the traditional teaching. The statistical inference, namely the determination of confidence intervals, was the content selected for this experience. It was intended show, first of all, that it is possible to promote, through the proposal methodology, the acquisition of basic skills in statistical inference and to promote the positive relationships between teachers and students. It presents also a comparative study between the methodologies used and their quantitative and qualitative results on two consecutive school years, in several indicators. The data used in the study were obtained from the students to the exam questions in the years 2010/2011 and 2011/2012, from the achievement of a working group in 2011/2012 and via the responses to a questionnaire (optional and anonymous also applied in 2011 / 2012. In terms of results, we emphasize a better performance of students in the examination questions in 2011/2012, the year that students used the software R, and a very favorable student’s perspective about

  13. Quantifying uncertainty on sediment loads using bootstrap confidence intervals

    Science.gov (United States)

    Slaets, Johanna I. F.; Piepho, Hans-Peter; Schmitter, Petra; Hilger, Thomas; Cadisch, Georg

    2017-01-01

    Load estimates are more informative than constituent concentrations alone, as they allow quantification of on- and off-site impacts of environmental processes concerning pollutants, nutrients and sediment, such as soil fertility loss, reservoir sedimentation and irrigation channel siltation. While statistical models used to predict constituent concentrations have been developed considerably over the last few years, measures of uncertainty on constituent loads are rarely reported. Loads are the product of two predictions, constituent concentration and discharge, integrated over a time period, which does not make it straightforward to produce a standard error or a confidence interval. In this paper, a linear mixed model is used to estimate sediment concentrations. A bootstrap method is then developed that accounts for the uncertainty in the concentration and discharge predictions, allowing temporal correlation in the constituent data, and can be used when data transformations are required. The method was tested for a small watershed in Northwest Vietnam for the period 2010-2011. The results showed that confidence intervals were asymmetric, with the highest uncertainty in the upper limit, and that a load of 6262 Mg year-1 had a 95 % confidence interval of (4331, 12 267) in 2010 and a load of 5543 Mg an interval of (3593, 8975) in 2011. Additionally, the approach demonstrated that direct estimates from the data were biased downwards compared to bootstrap median estimates. These results imply that constituent loads predicted from regression-type water quality models could frequently be underestimating sediment yields and their environmental impact.

  14. Confidence and Cognitive Test Performance

    Science.gov (United States)

    Stankov, Lazar; Lee, Jihyun

    2008-01-01

    This article examines the nature of confidence in relation to abilities, personality, and metacognition. Confidence scores were collected during the administration of Reading and Listening sections of the Test of English as a Foreign Language Internet-Based Test (TOEFL iBT) to 824 native speakers of English. Those confidence scores were correlated…

  15. Confidence Intervals for Cronbach's Coefficient Alpha Values

    NARCIS (Netherlands)

    A.J. Koning (Alex); Ph.H.B.F. Franses (Philip Hans)

    2003-01-01

    textabstractCoefficient Alpha, which is widely used in empirical research, estimates the reliability of a test consisting of parallel items. In practice it is difficult to compare values of alpha across studies as it depends on the number of items used. In this paper we provide a simple solution,

  16. Confidence intervals in Flow Forecasting by using artificial neural networks

    Science.gov (United States)

    Panagoulia, Dionysia; Tsekouras, George

    2014-05-01

    variable of different ANN structures [3]. The performance of each ANN structure is evaluated by the voting analysis based on eleven criteria, which are the root mean square error (RMSE), the correlation index (R), the mean absolute percentage error (MAPE), the mean percentage error (MPE), the mean percentage error (ME), the percentage volume in errors (VE), the percentage error in peak (MF), the normalized mean bias error (NMBE), the normalized root mean bias error (NRMSE), the Nash-Sutcliffe model efficiency coefficient (E) and the modified Nash-Sutcliffe model efficiency coefficient (E1). The next day flow for the test set is calculated using the best ANN structure's model. Consequently, the confidence intervals of various confidence levels for training, evaluation and test sets are compared in order to explore the generalisation dynamics of confidence intervals from training and evaluation sets. [1] H.S. Hippert, C.E. Pedreira, R.C. Souza, "Neural networks for short-term load forecasting: A review and evaluation," IEEE Trans. on Power Systems, vol. 16, no. 1, 2001, pp. 44-55. [2] G. J. Tsekouras, N.E. Mastorakis, F.D. Kanellos, V.T. Kontargyri, C.D. Tsirekis, I.S. Karanasiou, Ch.N. Elias, A.D. Salis, P.A. Kontaxis, A.A. Gialketsi: "Short term load forecasting in Greek interconnected power system using ANN: Confidence Interval using a novel re-sampling technique with corrective Factor", WSEAS International Conference on Circuits, Systems, Electronics, Control & Signal Processing, (CSECS '10), Vouliagmeni, Athens, Greece, December 29-31, 2010. [3] D. Panagoulia, I. Trichakis, G. J. Tsekouras: "Flow Forecasting via Artificial Neural Networks - A Study for Input Variables conditioned on atmospheric circulation", European Geosciences Union, General Assembly 2012 (NH1.1 / AS1.16 - Extreme meteorological and hydrological events induced by severe weather and climate change), Vienna, Austria, 22-27 April 2012.

  17. Effect size, confidence intervals and statistical power in psychological research.

    Directory of Open Access Journals (Sweden)

    Téllez A.

    2015-07-01

    Full Text Available Quantitative psychological research is focused on detecting the occurrence of certain population phenomena by analyzing data from a sample, and statistics is a particularly helpful mathematical tool that is used by researchers to evaluate hypotheses and make decisions to accept or reject such hypotheses. In this paper, the various statistical tools in psychological research are reviewed. The limitations of null hypothesis significance testing (NHST and the advantages of using effect size and its respective confidence intervals are explained, as the latter two measurements can provide important information about the results of a study. These measurements also can facilitate data interpretation and easily detect trivial effects, enabling researchers to make decisions in a more clinically relevant fashion. Moreover, it is recommended to establish an appropriate sample size by calculating the optimum statistical power at the moment that the research is designed. Psychological journal editors are encouraged to follow APA recommendations strictly and ask authors of original research studies to report the effect size, its confidence intervals, statistical power and, when required, any measure of clinical significance. Additionally, we must account for the teaching of statistics at the graduate level. At that level, students do not receive sufficient information concerning the importance of using different types of effect sizes and their confidence intervals according to the different types of research designs; instead, most of the information is focused on the various tools of NHST.

  18. Reporting Confidence Intervals and Effect Sizes: Collecting the Evidence

    Science.gov (United States)

    Zientek, Linda Reichwein; Ozel, Z. Ebrar Yetkiner; Ozel, Serkan; Allen, Jeff

    2012-01-01

    Confidence intervals (CIs) and effect sizes are essential to encourage meta-analytic thinking and to accumulate research findings. CIs provide a range of plausible values for population parameters with a degree of confidence that the parameter is in that particular interval. CIs also give information about how precise the estimates are. Comparison…

  19. Zero- vs. one-dimensional, parametric vs. non-parametric, and confidence interval vs. hypothesis testing procedures in one-dimensional biomechanical trajectory analysis.

    Science.gov (United States)

    Pataky, Todd C; Vanrenterghem, Jos; Robinson, Mark A

    2015-05-01

    Biomechanical processes are often manifested as one-dimensional (1D) trajectories. It has been shown that 1D confidence intervals (CIs) are biased when based on 0D statistical procedures, and the non-parametric 1D bootstrap CI has emerged in the Biomechanics literature as a viable solution. The primary purpose of this paper was to clarify that, for 1D biomechanics datasets, the distinction between 0D and 1D methods is much more important than the distinction between parametric and non-parametric procedures. A secondary purpose was to demonstrate that a parametric equivalent to the 1D bootstrap exists in the form of a random field theory (RFT) correction for multiple comparisons. To emphasize these points we analyzed six datasets consisting of force and kinematic trajectories in one-sample, paired, two-sample and regression designs. Results showed, first, that the 1D bootstrap and other 1D non-parametric CIs were qualitatively identical to RFT CIs, and all were very different from 0D CIs. Second, 1D parametric and 1D non-parametric hypothesis testing results were qualitatively identical for all six datasets. Last, we highlight the limitations of 1D CIs by demonstrating that they are complex, design-dependent, and thus non-generalizable. These results suggest that (i) analyses of 1D data based on 0D models of randomness are generally biased unless one explicitly identifies 0D variables before the experiment, and (ii) parametric and non-parametric 1D hypothesis testing provide an unambiguous framework for analysis when one׳s hypothesis explicitly or implicitly pertains to whole 1D trajectories. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Optimal Explicit Binomial Confidence Interval with Guaranteed Coverage Probability

    OpenAIRE

    Chen, Xinjia

    2008-01-01

    In this paper, we develop an approach for optimizing the explicit binomial confidence interval recently derived by Chen et al. The optimization reduces conservativeness while guaranteeing prescribed coverage probability.

  1. A quick method to calculate QTL confidence interval

    Indian Academy of Sciences (India)

    2011-08-19

    Aug 19, 2011 ... Introduction. There is much interest in the nature of the genetic varia- ... identified, interest turns to determining the confidence inter- val (CI) of QTL .... dropped until the total area of shaded parts equals significance to level, the position u and v are lower bound and upper bound of confidence interval for QTL ...

  2. An Optimization-Based Approach to Calculate Confidence Interval on Mean Value with Interval Data

    Directory of Open Access Journals (Sweden)

    Kais Zaman

    2014-01-01

    Full Text Available In this paper, we propose a methodology for construction of confidence interval on mean values with interval data for input variable in uncertainty analysis and design optimization problems. The construction of confidence interval with interval data is known as a combinatorial optimization problem. Finding confidence bounds on the mean with interval data has been generally considered an NP hard problem, because it includes a search among the combinations of multiple values of the variables, including interval endpoints. In this paper, we present efficient algorithms based on continuous optimization to find the confidence interval on mean values with interval data. With numerical experimentation, we show that the proposed confidence bound algorithms are scalable in polynomial time with respect to increasing number of intervals. Several sets of interval data with different numbers of intervals and type of overlap are presented to demonstrate the proposed methods. As against the current practice for the design optimization with interval data that typically implements the constraints on interval variables through the computation of bounds on mean values from the sampled data, the proposed approach of construction of confidence interval enables more complete implementation of design optimization under interval uncertainty.

  3. Bootstrap confidence intervals for the process capability index under half-logistic distribution

    OpenAIRE

    Wararit Panichkitkosolkul

    2012-01-01

    This study concerns the construction of bootstrap confidence intervals for theprocess capability index in the case of half-logistic distribution. The bootstrap confidence intervals applied consist of standard bootstrap confidence interval, percentile bootstrap confidence interval and bias-corrected percentile bootstrap confidence interval. Using Monte Carlo simulations, the estimated coverage probabilities and average widths ofbootstrap confidence intervals are compared, with results showing ...

  4. Confidence intervals for concentration and brightness from fluorescence fluctuation measurements.

    Science.gov (United States)

    Pryse, Kenneth M; Rong, Xi; Whisler, Jordan A; McConnaughey, William B; Jiang, Yan-Fei; Melnykov, Artem V; Elson, Elliot L; Genin, Guy M

    2012-09-05

    The theory of photon count histogram (PCH) analysis describes the distribution of fluorescence fluctuation amplitudes due to populations of fluorophores diffusing through a focused laser beam and provides a rigorous framework through which the brightnesses and concentrations of the fluorophores can be determined. In practice, however, the brightnesses and concentrations of only a few components can be identified. Brightnesses and concentrations are determined by a nonlinear least-squares fit of a theoretical model to the experimental PCH derived from a record of fluorescence intensity fluctuations. The χ(2) hypersurface in the neighborhood of the optimum parameter set can have varying degrees of curvature, due to the intrinsic curvature of the model, the specific parameter values of the system under study, and the relative noise in the data. Because of this varying curvature, parameters estimated from the least-squares analysis have varying degrees of uncertainty associated with them. There are several methods for assigning confidence intervals to the parameters, but these methods have different efficacies for PCH data. Here, we evaluate several approaches to confidence interval estimation for PCH data, including asymptotic standard error, likelihood joint-confidence region, likelihood confidence intervals, skew-corrected and accelerated bootstrap (BCa), and Monte Carlo residual resampling methods. We study these with a model two-dimensional membrane system for simplicity, but the principles are applicable as well to fluorophores diffusing in three-dimensional solution. Using simulated fluorescence fluctuation data, we find the BCa method to be particularly well-suited for estimating confidence intervals in PCH analysis, and several other methods to be less so. Using the BCa method and additional simulated fluctuation data, we find that confidence intervals can be reduced dramatically for a specific non-Gaussian beam profile. Copyright © 2012 Biophysical Society

  5. Continued misinterpretation of confidence intervals : Response to Miller and Ulrich

    NARCIS (Netherlands)

    Morey, Richard D.; Hoekstra, Rink; Rouder, Jeffrey N.; Wagenmakers, Eric-Jan

    2016-01-01

    Miller and Ulrich (2015) critique our claim (Hoekstra et al., Psychonomic Bulletin & Review, 21(5), 1157–1164, 2014), based on a survey given to researchers and students, of widespread misunderstanding of confidence intervals (CIs). They suggest that survey respondents may have interpreted the

  6. Continued misinterpretation of confidence intervals : Response to Miller and Ulrich

    NARCIS (Netherlands)

    Morey, R.D.; Hoekstra, R.; Rouder, J.N.; Wagenmakers, E.-J.

    Miller and Ulrich (2015) critique our claim (Hoekstra et al., Psychonomic Bulletin & Review, 21(5), 1157–1164, 2014), based on a survey given to researchers and students, of widespread misunderstanding of confidence intervals (CIs). They suggest that survey respondents may have interpreted the

  7. Constructing seasonally adjusted data with time-varying confidence intervals

    NARCIS (Netherlands)

    S.J. Koopman (Siem Jan); Ph.H.B.F. Franses (Philip Hans)

    2001-01-01

    textabstractSeasonal adjustment methods transform observed time series data into estimated data, where these estimated data are constructed such that they show no or almost no seasonal variation. An advantage of model-based methods is that these can provide confidence intervals around the seasonally

  8. Confidence intervals for intraclass correlation coefficients in variance components models

    NARCIS (Netherlands)

    Demetrashvili, Nino; Wit, Ernst C.; van den Heuvel, Edwin R.

    2016-01-01

    Confidence intervals for intraclass correlation coefficients in agreement studies with continuous outcomes are model-specific and no generic approach exists. This paper provides two generic approaches for intraclass correlation coefficients of the form Sigma q=1 2). The first approach uses

  9. Comparing confidence intervals for Goodman and Kruskal's gamma coefficient

    NARCIS (Netherlands)

    van der Ark, L.A.; van Aert, R.C.M.

    2015-01-01

    This study was motivated by the question which type of confidence interval (CI) one should use to summarize sample variance of Goodman and Kruskal's coefficient gamma. In a Monte-Carlo study, we investigated the coverage and computation time of the Goodman-Kruskal CI, the Cliff-consistent CI, the

  10. Confidence Intervals for Assessing Heterogeneity in Generalized Linear Mixed Models

    Science.gov (United States)

    Wagler, Amy E.

    2014-01-01

    Generalized linear mixed models are frequently applied to data with clustered categorical outcomes. The effect of clustering on the response is often difficult to practically assess partly because it is reported on a scale on which comparisons with regression parameters are difficult to make. This article proposes confidence intervals for…

  11. BINOMIAL AND POISSON CONFIDENCE INTERVALS AND ITS VARIANTS: A BIBLIOGRAPHY

    Directory of Open Access Journals (Sweden)

    Anwar Khurshid

    2010-09-01

    Full Text Available The binomial and Poisson distributions are basis to many aspects of statistical data analysis. This bibliography attempts to provide a comprehensive listing of available literature on calculating confidence intervals for binomial and Poisson distributions and its variants. The bibliography includes articles published in statistical and subject-matter journals and in conference proceedings.

  12. Likelihood-Based Confidence Intervals in Exploratory Factor Analysis

    Science.gov (United States)

    Oort, Frans J.

    2011-01-01

    In exploratory or unrestricted factor analysis, all factor loadings are free to be estimated. In oblique solutions, the correlations between common factors are free to be estimated as well. The purpose of this article is to show how likelihood-based confidence intervals can be obtained for rotated factor loadings and factor correlations, by…

  13. Likelihood-based confidence intervals in exploratory factor analysis

    NARCIS (Netherlands)

    Oort, F.J.

    2011-01-01

    In exploratory or unrestricted factor analysis, all factor loadings are free to be estimated. In oblique solutions, the correlations between common factors are free to be estimated as well. The purpose of this article is to show how likelihood-based confidence intervals can be obtained for rotated

  14. On Bayesian treatment of systematic uncertainties in confidence interval calculation

    CERN Document Server

    Tegenfeldt, Fredrik

    2005-01-01

    In high energy physics, a widely used method to treat systematic uncertainties in confidence interval calculations is based on combining a frequentist construction of confidence belts with a Bayesian treatment of systematic uncertainties. In this note we present a study of the coverage of this method for the standard Likelihood Ratio (aka Feldman & Cousins) construction for a Poisson process with known background and Gaussian or log-Normal distributed uncertainties in the background or signal efficiency. For uncertainties in the signal efficiency of upto 40 % we find over-coverage on the level of 2 to 4 % depending on the size of uncertainties and the region in signal space. Uncertainties in the background generally have smaller effect on the coverage. A considerable smoothing of the coverage curves is observed. A software package is presented which allows fast calculation of the confidence intervals for a variety of assumptions on shape and size of systematic uncertainties for different nuisance paramete...

  15. Confidence Intervals from Realizations of Simulated Nuclear Data

    Energy Technology Data Exchange (ETDEWEB)

    Younes, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ratkiewicz, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ressler, J. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-28

    Various statistical techniques are discussed that can be used to assign a level of confidence in the prediction of models that depend on input data with known uncertainties and correlations. The particular techniques reviewed in this paper are: 1) random realizations of the input data using Monte-Carlo methods, 2) the construction of confidence intervals to assess the reliability of model predictions, and 3) resampling techniques to impose statistical constraints on the input data based on additional information. These techniques are illustrated with a calculation of the keff value, based on the 235U(n, f) and 239Pu (n, f) cross sections.

  16. Achieving a Confidence Interval for Parameters Estimated by Simulation

    OpenAIRE

    Adam, Nabil R.

    1983-01-01

    This paper presents a procedure for determining the number of simulation observations required to achieve a preassigned confidence interval for means estimated by simulation. This procedure, which is simple to implement and efficient to use, is compared with two other methods for determining the required sample size in a simulation run. The empirical results show that this procedure gives good results in the precision of estimated means and in sample size requirement.

  17. Calculating and graphing within-subject confidence intervals for ANOVA.

    Science.gov (United States)

    Baguley, Thom

    2012-03-01

    The psychological and statistical literature contains several proposals for calculating and plotting confidence intervals (CIs) for within-subjects (repeated measures) ANOVA designs. A key distinction is between intervals supporting inference about patterns of means (and differences between pairs of means, in particular) and those supporting inferences about individual means. In this report, it is argued that CIs for the former are best accomplished by adapting intervals proposed by Cousineau (Tutorials in Quantitative Methods for Psychology, 1, 42-45, 2005) and Morey (Tutorials in Quantitative Methods for Psychology, 4, 61-64, 2008) so that nonoverlapping CIs for individual means correspond to a confidence for their difference that does not include zero. CIs for the latter can be accomplished by fitting a multilevel model. In situations in which both types of inference are of interest, the use of a two-tiered CI is recommended. Free, open-source, cross-platform software for such interval estimates and plots (and for some common alternatives) is provided in the form of R functions for one-way within-subjects and two-way mixed ANOVA designs. These functions provide an easy-to-use solution to the difficult problem of calculating and displaying within-subjects CIs.

  18. Bootstrap confidence intervals for the process capability index under half-logistic distribution

    Directory of Open Access Journals (Sweden)

    Wararit Panichkitkosolkul

    2012-07-01

    Full Text Available This study concerns the construction of bootstrap confidence intervals for theprocess capability index in the case of half-logistic distribution. The bootstrap confidence intervals applied consist of standard bootstrap confidence interval, percentile bootstrap confidence interval and bias-corrected percentile bootstrap confidence interval. Using Monte Carlo simulations, the estimated coverage probabilities and average widths ofbootstrap confidence intervals are compared, with results showing that the estimated coverage probabilities of the standard bootstrap confidence interval get closer to the nominal confidence level than those of the other bootstrap confidence intervals for all situations.

  19. On a linear method in bootstrap confidence intervals

    Directory of Open Access Journals (Sweden)

    Andrea Pallini

    2007-10-01

    Full Text Available A linear method for the construction of asymptotic bootstrap confidence intervals is proposed. We approximate asymptotically pivotal and non-pivotal quantities, which are smooth functions of means of n independent and identically distributed random variables, by using a sum of n independent smooth functions of the same analytical form. Errors are of order Op(n-3/2 and Op(n-2, respectively. The linear method allows a straightforward approximation of bootstrap cumulants, by considering the set of n independent smooth functions as an original random sample to be resampled with replacement.

  20. On confidence intervals for the hazard ratio in randomized clinical trials.

    Science.gov (United States)

    Lin, Dan-Yu; Dai, Luyan; Cheng, Gang; Sailer, Martin Oliver

    2016-12-01

    The log-rank test is widely used to compare two survival distributions in a randomized clinical trial, while partial likelihood (Cox, 1975) is the method of choice for making inference about the hazard ratio under the Cox (1972) proportional hazards model. The Wald 95% confidence interval of the hazard ratio may include the null value of 1 when the p-value of the log-rank test is less than 0.05. Peto et al. (1977) provided an estimator for the hazard ratio based on the log-rank statistic; the corresponding 95% confidence interval excludes the null value of 1 if and only if the p-value of the log-rank test is less than 0.05. However, Peto's estimator is not consistent, and the corresponding confidence interval does not have correct coverage probability. In this article, we construct the confidence interval by inverting the score test under the (possibly stratified) Cox model, and we modify the variance estimator such that the resulting score test for the null hypothesis of no treatment difference is identical to the log-rank test in the possible presence of ties. Like Peto's method, the proposed confidence interval excludes the null value if and only if the log-rank test is significant. Unlike Peto's method, however, this interval has correct coverage probability. An added benefit of the proposed confidence interval is that it tends to be more accurate and narrower than the Wald confidence interval. We demonstrate the advantages of the proposed method through extensive simulation studies and a colon cancer study. © 2016, The International Biometric Society.

  1. Secure and Usable Bio-Passwords based on Confidence Interval

    Directory of Open Access Journals (Sweden)

    Aeyoung Kim

    2017-02-01

    Full Text Available The most popular user-authentication method is the password. Many authentication systems try to enhance their security by enforcing a strong password policy, and by using the password as the first factor, something you know, with the second factor being something you have. However, a strong password policy and a multi-factor authentication system can make it harder for a user to remember the password and login in. In this paper a bio-password-based scheme is proposed as a unique authentication method, which uses biometrics and confidence interval sets to enhance the security of the log-in process and make it easier as well. The method offers a user-friendly solution for creating and registering strong passwords without the user having to memorize them. Here we also show the results of our experiments which demonstrate the efficiency of this method and how it can be used to protect against a variety of malicious attacks.

  2. The 95% confidence intervals of error rates and discriminant coefficients

    Directory of Open Access Journals (Sweden)

    Shuichi Shinmura

    2015-02-01

    Full Text Available Fisher proposed a linear discriminant function (Fisher’s LDF. From 1971, we analysed electrocardiogram (ECG data in order to develop the diagnostic logic between normal and abnormal symptoms by Fisher’s LDF and a quadratic discriminant function (QDF. Our four years research was inferior to the decision tree logic developed by the medical doctor. After this experience, we discriminated many data and found four problems of the discriminant analysis. A revised Optimal LDF by Integer Programming (Revised IP-OLDF based on the minimum number of misclassification (minimum NM criterion resolves three problems entirely [13, 18]. In this research, we discuss fourth problem of the discriminant analysis. There are no standard errors (SEs of the error rate and discriminant coefficient. We propose a k-fold crossvalidation method. This method offers a model selection technique and a 95% confidence intervals (C.I. of error rates and discriminant coefficients.

  3. Combating the scientific decline effect with confidence (intervals).

    Science.gov (United States)

    Groppe, David M

    2017-01-01

    A symptom of the need for greater reproducibility in scientific practice is the decline effect-the fact that the size of many experimental effects decline with subsequent study or fail to replicate entirely. A simple way to combat this problem is for scientists to more routinely use confidence intervals (CIs) in their work. CIs provide frequentist bounds on the true size of an effect and can reveal when a statistically significant effect is possibly too small to be reliable or when a large effect might have been missed due to insufficient statistical power. CIs are often lacking in psychophysiological reports, likely due to the large number of dependent variables, which complicates deriving and visualizing CIs. In this article, I explain the value of CIs and show how to compute them for analyses involving multiple variables in various ways that adjust the intervals for the greater uncertainty induced by multiple statistical comparisons. The methods are illustrated using a basic visual oddball ERP dataset and freely available MATLAB software. © 2016 Society for Psychophysiological Research.

  4. "Asymptotic Correction of Empirical Bayes Confidence Intervals and its Application to Small Area Estimation" (in Japanese)

    OpenAIRE

    Yoshitaka Sasase; Tatsuya Kubokawa

    2005-01-01

    This paper addresses the issue of constructing a confidence interval of a small area mean in a random effect or mixed effects linear model. A crude confidence interval based on the empirical Bayes method has the drawback that its coverage probability is much less than a nominal confidence coefficient. For improving on this confidence interval, the paper provides the procedure of adjusting the critical value, and the resulting confidence interval has a coverage probability which is identical t...

  5. Interpretando correctamente en salud pública estimaciones puntuales, intervalos de confianza y contrastes de hipótesis Accurate interpretation of point estimates, confidence intervals, and hypothesis tests in public health

    Directory of Open Access Journals (Sweden)

    Manuel G Scotto

    2003-12-01

    Full Text Available El presente ensayo trata de aclarar algunos conceptos utilizados habitualmente en el campo de investigación de la salud pública, que en numerosas situaciones son interpretados de manera incorrecta. Entre ellos encontramos la estimación puntual, los intervalos de confianza, y los contrastes de hipótesis. Estableciendo un paralelismo entre estos tres conceptos, podemos observar cuáles son sus diferencias más importantes a la hora de ser interpretados, tanto desde el punto de vista del enfoque clásico como desde la óptica bayesiana.This essay reviews some statistical concepts frequently used in public health research that are commonly misinterpreted. These include point estimates, confidence intervals, and hypothesis tests. By comparing them using the classical and the Bayesian perspectives, their interpretation becomes clearer.

  6. Optimal and Most Exact Confidence Intervals for Person Parameters in Item Response Theory Models

    Science.gov (United States)

    Doebler, Anna; Doebler, Philipp; Holling, Heinz

    2013-01-01

    The common way to calculate confidence intervals for item response theory models is to assume that the standardized maximum likelihood estimator for the person parameter [theta] is normally distributed. However, this approximation is often inadequate for short and medium test lengths. As a result, the coverage probabilities fall below the given…

  7. Introduction to Sample Size Choice for Confidence Intervals Based on "t" Statistics

    Science.gov (United States)

    Liu, Xiaofeng Steven; Loudermilk, Brandon; Simpson, Thomas

    2014-01-01

    Sample size can be chosen to achieve a specified width in a confidence interval. The probability of obtaining a narrow width given that the confidence interval includes the population parameter is defined as the power of the confidence interval, a concept unfamiliar to many practitioners. This article shows how to utilize the Statistical Analysis…

  8. Confidence intervals for parameters of IWD based on MLE and bootstrap

    OpenAIRE

    Mostafa MohieEl-Din; Fathy Riad; Mohamed El-Sayed

    2013-01-01

    In this paper, we will study the joint confidence regions for the parameters of inverse Weibull distribution (IWD) in the point of view of record values. Based on this new censoring scheme, the approximate confidence intervals and percentile bootstrap confidence intervals as well as approximate joint confidence region for the parameters of IWD, are developed. One of the applications of the joint confidence regions of the parameters is to find confidence bounds for the functions of the paramet...

  9. Testing 40 Predictions from the Transtheoretical Model Again, with Confidence

    Science.gov (United States)

    Velicer, Wayne F.; Brick, Leslie Ann D.; Fava, Joseph L.; Prochaska, James O.

    2013-01-01

    Testing Theory-based Quantitative Predictions (TTQP) represents an alternative to traditional Null Hypothesis Significance Testing (NHST) procedures and is more appropriate for theory testing. The theory generates explicit effect size predictions and these effect size estimates, with related confidence intervals, are used to test the predictions.…

  10. An Introduction to Confidence Intervals for Both Statistical Estimates and Effect Sizes.

    Science.gov (United States)

    Capraro, Mary Margaret

    This paper summarizes methods of estimating confidence intervals, including classical intervals and intervals for effect sizes. The recent American Psychological Association (APA) Task Force on Statistical Inference report suggested that confidence intervals should always be reported, and the fifth edition of the APA "Publication Manual"…

  11. A LabVIEW program for determining confidence intervals of Abel-inverted radial emission profiles

    Energy Technology Data Exchange (ETDEWEB)

    Chan, George C.-Y. [Department of Chemistry, Indiana University, Bloomington, IN 47405 (United States); Hieftje, Gary M. [Department of Chemistry, Indiana University, Bloomington, IN 47405 (United States)]. E-mail: hieftje@indiana.edu

    2005-11-15

    A LabVIEW-based program for the determination of confidence intervals in Abel inversion is described in detail. Confidence intervals are determined from the noise level in the input lateral-emission profile. It is first assumed that the noise-free lateral profile is a smooth and continuous function which can be satisfactorily approximated by a polynomial fit. Random noise is then added to produce a profile that is statistically identical to the experimental lateral profile. Because the number of generated lateral profiles can be as large as desired, the corresponding Abel-inverted radial profiles provide a basis for determination of the confidence intervals. The program is capable of determining the optimal order of the fitting polynomial for the input lateral profile. Two methods for computing the Abel inversion calculation, the Nestor-Olsen and the Hankel-Fourier algorithms, are built into the program. If necessary, the input lateral profile can be smoothed by a built-in moving-average function. A detailed description of the program and its associated functions is presented, followed by a characterization of its performance in the determination of Abel-inversion confidence intervals for several test emission profiles.

  12. MorePower 6.0 for ANOVA with relational confidence intervals and Bayesian analysis.

    Science.gov (United States)

    Campbell, Jamie I D; Thompson, Valerie A

    2012-12-01

    MorePower 6.0 is a flexible freeware statistical calculator that computes sample size, effect size, and power statistics for factorial ANOVA designs. It also calculates relational confidence intervals for ANOVA effects based on formulas from Jarmasz and Hollands (Canadian Journal of Experimental Psychology 63:124-138, 2009), as well as Bayesian posterior probabilities for the null and alternative hypotheses based on formulas in Masson (Behavior Research Methods 43:679-690, 2011). The program is unique in affording direct comparison of these three approaches to the interpretation of ANOVA tests. Its high numerical precision and ability to work with complex ANOVA designs could facilitate researchers' attention to issues of statistical power, Bayesian analysis, and the use of confidence intervals for data interpretation. MorePower 6.0 is available at https://wiki.usask.ca/pages/viewpageattachments.action?pageId=420413544 .

  13. A novel nonparametric confidence interval for differences of proportions for correlated binary data.

    Science.gov (United States)

    Duan, Chongyang; Cao, Yingshu; Zhou, Lizhi; Tan, Ming T; Chen, Pingyan

    2016-11-16

    Various confidence interval estimators have been developed for differences in proportions resulted from correlated binary data. However, the width of the mostly recommended Tango's score confidence interval tends to be wide, and the computing burden of exact methods recommended for small-sample data is intensive. The recently proposed rank-based nonparametric method by treating proportion as special areas under receiver operating characteristic provided a new way to construct the confidence interval for proportion difference on paired data, while the complex computation limits its application in practice. In this article, we develop a new nonparametric method utilizing the U-statistics approach for comparing two or more correlated areas under receiver operating characteristics. The new confidence interval has a simple analytic form with a new estimate of the degrees of freedom of n - 1. It demonstrates good coverage properties and has shorter confidence interval widths than that of Tango. This new confidence interval with the new estimate of degrees of freedom also leads to coverage probabilities that are an improvement on the rank-based nonparametric confidence interval. Comparing with the approximate exact unconditional method, the nonparametric confidence interval demonstrates good coverage properties even in small samples, and yet they are very easy to implement computationally. This nonparametric procedure is evaluated using simulation studies and illustrated with three real examples. The simplified nonparametric confidence interval is an appealing choice in practice for its ease of use and good performance. © The Author(s) 2016.

  14. Graphing within-subjects confidence intervals using SPSS and S-Plus.

    Science.gov (United States)

    Wright, Daniel B

    2007-02-01

    Within-subjects confidence intervals are often appropriate to report and to display. Loftus and Masson (1994) have reported methods to calculate these, and their use is becoming common. In the present article, procedures for calculating within-subjects confidence intervals in SPSS and S-Plus are presented (an R version is on the accompanying Web site). The procedure in S-Plus allows the user to report the bias corrected and adjusted bootstrap confidence intervals as well as the standard confidence intervals based on traditional methods. The presented code can be easily altered to fit the individual user's needs.

  15. Applying Bootstrap Resampling to Compute Confidence Intervals for Various Statistics with R

    Science.gov (United States)

    Dogan, C. Deha

    2017-01-01

    Background: Most of the studies in academic journals use p values to represent statistical significance. However, this is not a good indicator of practical significance. Although confidence intervals provide information about the precision of point estimation, they are, unfortunately, rarely used. The infrequent use of confidence intervals might…

  16. What Confidence Intervals "Really" Do and Why They Are So Important for Middle Grades Educational Research

    Science.gov (United States)

    Skidmore, Susan Troncoso

    2009-01-01

    Recommendations made by major educational and psychological organizations (American Educational Research Association, 2006; American Psychological Association, 2001) call for researchers to regularly report confidence intervals. The purpose of the present paper is to provide support for the use of confidence intervals. To contextualize this…

  17. Simultaneous confidence intervals for a success probability and intraclass correlation, with an application to screening mammography.

    Science.gov (United States)

    Kim, Jongphil; Lee, Ji-Hyun

    2013-11-01

    This paper provides asymptotic simultaneous confidence intervals for a success probability and intraclass correlation of the beta-binomial model, based on the maximum likelihood estimator approach. The coverage probabilities of those intervals are evaluated. An application to screening mammography is presented as an example. The individual and simultaneous confidence intervals for sensitivity and specificity and the corresponding intraclass correlations are investigated. Two additional examples using influenza data and sex ratio data among sibships are also considered, where the individual and simultaneous confidence intervals are provided. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Exact parametric confidence intervals for Bland-Altman limits of agreement.

    Science.gov (United States)

    Carkeet, Andrew

    2015-03-01

    The previous literature on Bland-Altman analysis only describes approximate methods for calculating confidence intervals for 95% limits of agreement (LoAs). This article describes exact methods for calculating such confidence intervals based on the assumption that differences in measurement pairs are normally distributed. Two basic situations are considered for calculating LoA confidence intervals: the first, where LoAs are considered individually (i.e., using one-sided tolerance factors for a normal distribution); and the second, where LoAs are considered as a pair (i.e., using two-sided tolerance factors for a normal distribution). Equations underlying the calculation of exact confidence limits are briefly outlined. To assist in determining confidence intervals for LoAs (considered individually and as a pair), tables of coefficients have been included for degrees of freedom between 1 and 1000. Numerical examples, showing the use of the tables for calculating confidence limits for Bland-Altman LoAs, have been provided. Exact confidence intervals for LoAs can differ considerably from the Bland and Altman approximate method, especially for sample sizes that are not large. There are better, more precise methods for calculating confidence intervals for LoAs than the Bland and Altman approximate method, although even an approximate calculation of confidence intervals for LoAs is likely to be better than none at all. Reporting confidence limits for LoAs considered as a pair is appropriate for most situations; however, there may be circumstances where it is appropriate to report confidence limits for LoAs considered individually.

  19. Precise confidence intervals of regression-based reference limits: Method comparisons and sample size requirements.

    Science.gov (United States)

    Shieh, Gwowen

    2017-12-01

    Covariate-dependent reference limits have been extensively applied in biology and medicine for determining the substantial magnitude and relative importance of quantitative measurements. Confidence interval and sample size procedures are available for studying regression-based reference limits. However, the existing popular methods employ different technical simplifications and are applicable only in certain limited situations. This paper describes exact confidence intervals of regression-based reference limits and compares the exact approach with the approximate methods under a wide range of model configurations. Using the ratio between the widths of confidence interval and reference interval as the relative precision index, optimal sample size procedures are presented for precise interval estimation under expected ratio and tolerance probability considerations. Simulation results show that the approximate interval methods using normal distribution have inaccurate confidence limits. The exact confidence intervals dominate the approximate procedures in one- and two-sided coverage performance. Unlike the current simplifications, the proposed sample size procedures integrate all key factors including covariate features in the optimization process and are suitable for various regression-based reference limit studies with potentially diverse configurations. The exact interval estimation has theoretical and practical advantages over the approximate methods. The corresponding sample size procedures and computing algorithms are also presented to facilitate the data analysis and research design of regression-based reference limits. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Teach a Confidence Interval for the Median in the First Statistics Course

    Science.gov (United States)

    Howington, Eric B.

    2017-01-01

    Few introductory statistics courses consider statistical inference for the median. This article argues in favour of adding a confidence interval for the median to the first statistics course. Several methods suitable for introductory statistics students are identified and briefly reviewed.

  1. Asymptotic coverage probabilities of bootstrap percentile confidence intervals for constrained parameters

    OpenAIRE

    Wang, Chunlin; Marriott, Paul; Li, Pengfei

    2017-01-01

    The asymptotic behaviour of the commonly used bootstrap percentile confidence interval is investigated when the parameters are subject to linear inequality constraints. We concentrate on the important one- and two-sample problems with data generated from general parametric distributions in the natural exponential family. The focus of this paper is on quantifying the coverage probabilities of the parametric bootstrap percentile confidence intervals, in particular their limiting behaviour near ...

  2. Empirical Likelihood Confidence Intervals under the Rao-Hartley-Cochran Sampling Design

    OpenAIRE

    Berger, Yves G.

    2014-01-01

    The Hartley-Rao-Cochran (RHC) sampling design (Rao et al., 1962) is a popular unequal probability sampling design. We show how empirical likelihood confidence intervals can be derived under this sampling design. Berger and De La Riva Torres (2012) proposed an empirical likelihood approach which can be used for point estimation and to construct confidence intervals under complex sampling designs. We show how this approach can be adjusted for the RHC sampling design. The proposed approach intri...

  3. Modal confidence factor in vibration testing

    Science.gov (United States)

    Ibrahim, S. R.

    1978-01-01

    The modal confidence factor (MCF) is a number calculated for every identified mode for a structure under test. The MCF varies from 0.00 for a distorted nonlinear, or noise mode to 100.0 for a pure structural mode. The theory of the MCF is based on the correlation that exists between the modal deflection at a certain station and the modal deflection at the same station delayed in time. The theory and application of the MCF are illustrated by two experiments. The first experiment deals with simulated responses from a two-degree-of-freedom system with 20%, 40%, and 100% noise added. The second experiment was run on a generalized payload model. The free decay response from the payload model contained 22% noise.

  4. The Applicability of Confidence Intervals of Quantiles for the Generalized Logistic Distribution

    Science.gov (United States)

    Shin, H.; Heo, J.; Kim, T.; Jung, Y.

    2007-12-01

    The generalized logistic (GL) distribution has been widely used for frequency analysis. However, there is a little study related to the confidence intervals that indicate the prediction accuracy of distribution for the GL distribution. In this paper, the estimation of the confidence intervals of quantiles for the GL distribution is presented based on the method of moments (MOM), maximum likelihood (ML), and probability weighted moments (PWM) and the asymptotic variances of each quantile estimator are derived as functions of the sample sizes, return periods, and parameters. Monte Carlo simulation experiments are also performed to verify the applicability of the derived confidence intervals of quantile. As the results, the relative bias (RBIAS) and relative root mean square error (RRMSE) of the confidence intervals generally increase as return period increases and reverse as sample size increases. And PWM for estimating the confidence intervals performs better than the other methods in terms of RRMSE when the data is almost symmetric while ML shows the smallest RBIAS and RRMSE when the data is more skewed and sample size is moderately large. The GL model was applied to fit the distribution of annual maximum rainfall data. The results show that there are little differences in the estimated quantiles between ML and PWM while distinct differences in MOM.

  5. Comparisons of multivariate GR&R methods using bootstrap confidence interval

    Directory of Open Access Journals (Sweden)

    Rogério Santana Peruchi

    2016-08-01

    Full Text Available This paper aimed to compare the performance of multivariate GR&R (gage repeatability and reproducibility studies based on PCA (principal component analysis and Manova (multivariate analysis of variance methods. To estimate the multivariate gauge index, geometric and arithmetic means have been implemented with and without weighting strategies. Bootstrap confidence interval based on BCa (bias-corrected and accelerated method has been adopted to determine multivariate gauge index adequacy. This confidence interval was calculated for the mean of univariate gauge indices estimated from each quality characteristic. The result analyses have shown that weighted approaches provided the best estimates of gauge index in multivariate GR&R studies.

  6. WASP (Write a Scientific Paper) using Excel - 6: Standard error and confidence interval.

    Science.gov (United States)

    Grech, Victor

    2018-02-02

    The calculation of descriptive statistics includes the calculation of standard error and confidence interval, an inevitable component of data analysis in inferential statistics. This paper provides pointers as to how to do this in Microsoft Excel™. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Evolution of heterogeneity (I2) estimates and their 95% confidence intervals in large meta-analyses

    DEFF Research Database (Denmark)

    Thorlund, Kristian; Imberger, Georgina; Johnston, Bradley C

    2012-01-01

    by sampling error. Recent studies have raised concerns about the reliability of I(2) estimates, due to their dependence on the precision of included trials and time-dependent biases. Authors have also advocated use of 95% confidence intervals (CIs) to express the uncertainty associated with I(2) estimates...

  8. The Robustness of Confidence Intervals for Coefficient Alpha under Violation of the Assumption of Essential Parallelism.

    Science.gov (United States)

    Barchard, Kimberly A.; Hakstian, A. Ralph

    1997-01-01

    Two studies, both using Type 12 sampling, are presented in which the effects of violating the assumption of essential parallelism in setting confidence intervals are studied. Results indicate that as long as data manifest properties of essential parallelism, the two methods studied maintain precise Type I error control. (SLD)

  9. Applying a Score Confidence Interval to Aiken's Item Content-Relevance Index

    Science.gov (United States)

    Penfield, Randall D.; Giacobbi, Peter R., Jr

    2004-01-01

    Item content-relevance is an important consideration for researchers when developing scales used to measure psychological constructs. Aiken (1980) proposed a statistic, "V," that can be used to summarize item content-relevance ratings obtained from a panel of expert judges. This article proposes the application of the Score confidence interval to…

  10. Comparing confidence intervals for Goodman and Kruskal’s gamma coefficient

    NARCIS (Netherlands)

    van der Ark, L.A.; van Aert, R.C.M.

    2015-01-01

    This study was motivated by the question which type of confidence interval (CI) one should use to summarize sample variance of Goodman and Kruskal's coefficient gamma. In a Monte-Carlo study, we investigated the coverage and computation time of the Goodman–Kruskal CI, the Cliff-consistent CI, the

  11. Reliability, Validity, Effects Sizes, and Confidence Intervals in Multicultural Teaching and Learning Research and Scholarship

    Science.gov (United States)

    Sapp, Marty

    2012-01-01

    Like many journals within education, for "Multicultural Learning and Teaching," this writer found little written on measurement, effect sizes, and confidence intervals; therefore, the purpose of this article is to address these factors. The effect of not addressing these issues is that a basic foundation of science cannot be established…

  12. Performing Contrast Analysis in Factorial Designs: From NHST to Confidence Intervals and Beyond

    Science.gov (United States)

    Wiens, Stefan; Nilsson, Mats E.

    2017-01-01

    Because of the continuing debates about statistics, many researchers may feel confused about how to analyze and interpret data. Current guidelines in psychology advocate the use of effect sizes and confidence intervals (CIs). However, researchers may be unsure about how to extract effect sizes from factorial designs. Contrast analysis is helpful…

  13. Likelihood based observability analysis and confidence intervals for predictions of dynamic models

    Directory of Open Access Journals (Sweden)

    Kreutz Clemens

    2012-09-01

    Full Text Available Abstract Background Predicting a system’s behavior based on a mathematical model is a primary task in Systems Biology. If the model parameters are estimated from experimental data, the parameter uncertainty has to be translated into confidence intervals for model predictions. For dynamic models of biochemical networks, the nonlinearity in combination with the large number of parameters hampers the calculation of prediction confidence intervals and renders classical approaches as hardly feasible. Results In this article reliable confidence intervals are calculated based on the prediction profile likelihood. Such prediction confidence intervals of the dynamic states can be utilized for a data-based observability analysis. The method is also applicable if there are non-identifiable parameters yielding to some insufficiently specified model predictions that can be interpreted as non-observability. Moreover, a validation profile likelihood is introduced that should be applied when noisy validation experiments are to be interpreted. Conclusions The presented methodology allows the propagation of uncertainty from experimental to model predictions. Although presented in the context of ordinary differential equations, the concept is general and also applicable to other types of models. Matlab code which can be used as a template to implement the method is provided at http://www.fdmold.uni-freiburg.de/∼ckreutz/PPL.

  14. Binomial Distribution Sample Confidence Intervals Estimation 7. Absolute Risk Reduction and ARR-like Expressions

    Directory of Open Access Journals (Sweden)

    Andrei ACHIMAŞ CADARIU

    2004-08-01

    Full Text Available Assessments of a controlled clinical trial suppose to interpret some key parameters as the controlled event rate, experimental event date, relative risk, absolute risk reduction, relative risk reduction, number needed to treat when the effect of the treatment are dichotomous variables. Defined as the difference in the event rate between treatment and control groups, the absolute risk reduction is the parameter that allowed computing the number needed to treat. The absolute risk reduction is compute when the experimental treatment reduces the risk for an undesirable outcome/event. In medical literature when the absolute risk reduction is report with its confidence intervals, the method used is the asymptotic one, even if it is well know that may be inadequate. The aim of this paper is to introduce and assess nine methods of computing confidence intervals for absolute risk reduction and absolute risk reduction – like function.Computer implementations of the methods use the PHP language. Methods comparison uses the experimental errors, the standard deviations, and the deviation relative to the imposed significance level for specified sample sizes. Six methods of computing confidence intervals for absolute risk reduction and absolute risk reduction-like functions were assessed using random binomial variables and random sample sizes.The experiments shows that the ADAC, and ADAC1 methods obtains the best overall performance of computing confidence intervals for absolute risk reduction.

  15. Computationally efficient permutation-based confidence interval estimation for tail-area FDR

    Directory of Open Access Journals (Sweden)

    Joshua eMillstein

    2013-09-01

    Full Text Available Challenges of satisfying parametric assumptions in genomic settings with thousands or millions of tests have led investigators to combine powerful False Discovery Rate (FDR approaches with computationally expensive but exact permutation testing. We describe a computationally efficient permutation-based approach that includes a tractable estimator of the proportion of true null hypotheses, the variance of the log of tail-area FDR, and a confidence interval (CI estimator, which accounts for the number of permutations conducted and dependencies between tests. The CI estimator applies a binomial distribution and an overdispersion parameter to counts of positive tests. The approach is general with regards to the distribution of the test statistic, it performs favorably in comparison to other approaches, and reliable FDR estimates are demonstrated with as few as 10 permutations. An application of this approach to relate sleep patterns to gene expression patterns in mouse hypothalamus yielded a set of 11 transcripts associated with 24 hour REM sleep (FDR = .15 (.08, .26. Two of the corresponding genes, Sfrp1 and Sfrp4, are involved in wnt signaling and several others, Irf7, Ifit1, Iigp2, and Ifih1, have links to interferon signaling. These genes would have been overlooked had a typical a priori FDR threshold such as 0.05 or 0.1 been applied. The CI provides the flexibility for choosing a significance threshold based on tolerance for false discoveries and precision of the FDR estimate. That is, it frees the investigator to use a more data-driven approach to define significance, such as the minimum estimated FDR, an option that is especially useful for weak effects, often observed in studies of complex diseases.

  16. The direct integral method for confidence intervals for the ratio of two location parameters.

    Science.gov (United States)

    Wang, Yanqing; Wang, Suojin; Carroll, Raymond J

    2015-09-01

    In a relative risk analysis of colorectal caner on nutrition intake scores across genders, we show that, surprisingly, when comparing the relative risks for men and women based on the index of a weighted sum of various nutrition scores, the problem reduces to forming a confidence interval for the ratio of two (asymptotically) normal random variables. The latter is an old problem, with a substantial literature. However, our simulation results suggest that existing methods often either give inaccurate coverage probabilities or have a positive probability to produce confidence intervals with infinite length. Motivated by such a problem, we develop a new methodology which we call the Direct Integral Method for Ratios (DIMER), which, unlike the other methods, is based directly on the distribution of the ratio. In simulations, we compare this method to many others. These simulations show that, generally, DIMER more closely achieves the nominal confidence level, and in those cases that the other methods achieve the nominal levels, DIMER has comparable confidence interval lengths. The methodology is then applied to a real data set, and with follow up simulations. © 2015, The International Biometric Society.

  17. Confidence intervals for return levels for the peaks-over-threshold approach

    Science.gov (United States)

    Schendel, Thomas; Thongwichian, Rossukon

    2017-01-01

    The peaks-over-threshold (POT) approach is an important alternative to the annual block maxima (ABM) method in flood frequency analysis. POT requires the mathematical description of both, the number of exceedances over the threshold as well as the values of those exceedances. Regardless the method, estimates of extreme flood events are typically associated with a large range of uncertainty, which is usually showcased by appropriate confidence intervals (CIs). However, existing methods to estimate CIs for return levels for the POT approach have mostly neglected its dual-domain character and focused on the distribution of the magnitudes only. We present here a customization of two methods, the Profile Likelihood (PL) and test inversion bootstrap (TIB), which account for the dual-domain structure of POT. Both, PL and TIB, are in the framework of ABM already successfully employed for estimating CIs of extreme flood events. A comparison of the performance of the estimated CIs (in terms of coverage error) of the PL, TIB, and percentile bootstrap is done. As result, it is seen that both the lower and upper boundary of the CIs are strongly underestimated for the percentile bootstrap approach. A similar effect (although in a much less pronounced way) can be observed for PL. The performance of the TIB is usually superior to the percentile bootstrap and PL and yielded reasonable estimates for the CIs for large return periods.

  18. Evaluating the utility of hexapod species for calculating a confidence interval about a succession based postmortem interval estimate.

    Science.gov (United States)

    Perez, Anne E; Haskell, Neal H; Wells, Jeffrey D

    2014-08-01

    Carrion insect succession patterns have long been used to estimate the postmortem interval (PMI) during a death investigation. However, no published carrion succession study included sufficient replication to calculate a confidence interval about a PMI estimate based on occurrence data. We exposed 53 pig carcasses (16±2.5 kg), near the likely minimum needed for such statistical analysis, at a site in north-central Indiana, USA, over three consecutive summer seasons. Insects and Collembola were sampled daily from each carcass for a total of 14 days, by this time each was skeletonized. The criteria for judging a life stage of a given species to be potentially useful for succession-based PMI estimation were (1) nonreoccurrence (observed during a single period of presence on a corpse), and (2) found in a sufficiently large proportion of carcasses to support a PMI confidence interval. For this data set that proportion threshold is 45/53. Of the 266 species collected and identified, none was nonreoccuring in that each showed at least a gap of one day on a single carcass. If the definition of nonreoccurrence is relaxed to include such a single one-day gap the larval forms of Necrophilaamericana, Fanniascalaris, Cochliomyia macellaria, Phormiaregina, and Luciliaillustris satisfied these two criteria. Adults of Creophilus maxillosus, Necrobiaruficollis, and Necrodessurinamensis were common and showed only a few, single-day gaps in occurrence. C.maxillosus, P.regina, and L.illustris displayed exceptional forensic utility in that they were observed on every carcass. Although these observations were made at a single site during one season of the year, the species we found to be useful have large geographic ranges. We suggest that future carrion insect succession research focus only on a limited set of species with high potential forensic utility so as to reduce sample effort per carcass and thereby enable increased experimental replication. Copyright © 2014 Elsevier Ireland

  19. Improved confidence interval for average annual percent change in trend analysis.

    Science.gov (United States)

    Kim, Hyune-Ju; Luo, Jun; Chen, Huann-Sheng; Green, Don; Buckman, Dennis; Byrne, Jeffrey; Feuer, Eric J

    2017-08-30

    This paper considers an improved confidence interval for the average annual percent change in trend analysis, which is based on a weighted average of the regression slopes in the segmented line regression model with unknown change points. The performance of the improved confidence interval proposed by Muggeo is examined for various distribution settings, and two new methods are proposed for further improvement. The first method is practically equivalent to the one proposed by Muggeo, but its construction is simpler, and it is modified to use the t-distribution instead of the standard normal distribution. The second method is based on the empirical distribution of the residuals and the resampling using a uniform random sample, and its satisfactory performance is indicated by a simulation study. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  20. Confidence Intervals Verification for Simulated Error Rate Performance of Wireless Communication System

    KAUST Repository

    Smadi, Mahmoud A.

    2012-12-06

    In this paper, we derived an efficient simulation method to evaluate the error rate of wireless communication system. Coherent binary phase-shift keying system is considered with imperfect channel phase recovery. The results presented demonstrate the system performance under very realistic Nakagami-m fading and additive white Gaussian noise channel. On the other hand, the accuracy of the obtained results is verified through running the simulation under a good confidence interval reliability of 95 %. We see that as the number of simulation runs N increases, the simulated error rate becomes closer to the actual one and the confidence interval difference reduces. Hence our results are expected to be of significant practical use for such scenarios. © 2012 Springer Science+Business Media New York.

  1. Growth Estimators and Confidence Intervals for the Mean of Negative Binomial Random Variables with Unknown Dispersion

    Directory of Open Access Journals (Sweden)

    David Shilane

    2013-01-01

    Full Text Available The negative binomial distribution becomes highly skewed under extreme dispersion. Even at moderately large sample sizes, the sample mean exhibits a heavy right tail. The standard normal approximation often does not provide adequate inferences about the data's expected value in this setting. In previous work, we have examined alternative methods of generating confidence intervals for the expected value. These methods were based upon Gamma and Chi Square approximations or tail probability bounds such as Bernstein's inequality. We now propose growth estimators of the negative binomial mean. Under high dispersion, zero values are likely to be overrepresented in the data. A growth estimator constructs a normal-style confidence interval by effectively removing a small, predetermined number of zeros from the data. We propose growth estimators based upon multiplicative adjustments of the sample mean and direct removal of zeros from the sample. These methods do not require estimating the nuisance dispersion parameter. We will demonstrate that the growth estimators' confidence intervals provide improved coverage over a wide range of parameter values and asymptotically converge to the sample mean. Interestingly, the proposed methods succeed despite adding both bias and variance to the normal approximation.

  2. Comparison of confidence interval methods for an intra-class correlation coefficient (ICC).

    Science.gov (United States)

    Ionan, Alexei C; Polley, Mei-Yin C; McShane, Lisa M; Dobbin, Kevin K

    2014-11-22

    The intraclass correlation coefficient (ICC) is widely used in biomedical research to assess the reproducibility of measurements between raters, labs, technicians, or devices. For example, in an inter-rater reliability study, a high ICC value means that noise variability (between-raters and within-raters) is small relative to variability from patient to patient. A confidence interval or Bayesian credible interval for the ICC is a commonly reported summary. Such intervals can be constructed employing either frequentist or Bayesian methodologies. This study examines the performance of three different methods for constructing an interval in a two-way, crossed, random effects model without interaction: the Generalized Confidence Interval method (GCI), the Modified Large Sample method (MLS), and a Bayesian method based on a noninformative prior distribution (NIB). Guidance is provided on interval construction method selection based on study design, sample size, and normality of the data. We compare the coverage probabilities and widths of the different interval methods. We show that, for the two-way, crossed, random effects model without interaction, care is needed in interval method selection because the interval estimates do not always have properties that the user expects. While different methods generally perform well when there are a large number of levels of each factor, large differences between the methods emerge when the number of one or more factors is limited. In addition, all methods are shown to lack robustness to certain hard-to-detect violations of normality when the sample size is limited. Decision rules and software programs for interval construction are provided for practical implementation in the two-way, crossed, random effects model without interaction. All interval methods perform similarly when the data are normal and there are sufficient numbers of levels of each factor. The MLS and GCI methods outperform the NIB when one of the factors has a

  3. Study of coverage of confidence intervals for the standardized mortality ratio in studies with missing death certificates.

    Science.gov (United States)

    Timkova, Jana; Kotik, Lukas; Tomasek, Ladislav

    2017-11-30

    This paper assesses the coverage probability of commonly used confidence intervals for the standardized mortality ratio (SMR) when death certificates are missing. It also proposes alternative confidence interval approaches with coverage probabilities close to .95. In epidemiology, the SMR is an important measure of risk of disease mortality (or incidence) to compare a specific group to a reference population. The appropriate confidence interval for the SMR is crucial, especially when the SMR is close to 1.0 and the statistical significance of the risk needs to be determined. There are several ways to calculate confidence intervals, depending on a study characteristics (ie, studies with small number of deaths, studies with small counts, aggregate SMRs based on several countries or time periods, and studies with missing death certificates). This paper summarizes the most commonly used confidence intervals and newly applies several existing approaches not previously used for SMR confidence intervals. The coverage probability and length of the different confidence intervals are assessed using a simulation study and different scenarios. The performance of the confidence intervals for the lung cancer SMR and all other cancer SMR is also assessed using the dataset of French and Czech uranium miners. Finally, the most appropriate confidence intervals to use under different study scenarios are recommended. Copyright © 2017 John Wiley & Sons, Ltd.

  4. A Comparison of Various Stress Rupture Life Models for Orbiter Composite Pressure Vessels and Confidence Intervals

    Science.gov (United States)

    Grimes-Ledesma, Lorie; Murthy, Pappu L. N.; Phoenix, S. Leigh; Glaser, Ronald

    2007-01-01

    In conjunction with a recent NASA Engineering and Safety Center (NESC) investigation of flight worthiness of Kevlar Overwrapped Composite Pressure Vessels (COPVs) on board the Orbiter, two stress rupture life prediction models were proposed independently by Phoenix and by Glaser. In this paper, the use of these models to determine the system reliability of 24 COPVs currently in service on board the Orbiter is discussed. The models are briefly described, compared to each other, and model parameters and parameter uncertainties are also reviewed to understand confidence in reliability estimation as well as the sensitivities of these parameters in influencing overall predicted reliability levels. Differences and similarities in the various models will be compared via stress rupture reliability curves (stress ratio vs. lifetime plots). Also outlined will be the differences in the underlying model premises, and predictive outcomes. Sources of error and sensitivities in the models will be examined and discussed based on sensitivity analysis and confidence interval determination. Confidence interval results and their implications will be discussed for the models by Phoenix and Glaser.

  5. Confidence intervals for the common intraclass correlation in the analysis of clustered binary responses.

    Science.gov (United States)

    Saha, Krishna K; Wang, Suojin

    2017-10-09

    In cluster randomized trials, it is often of interest to estimate the common intraclass correlation at the design stage for sample size and power calculations, which are greatly affected by the value of a common intraclass correlation. In this article, we construct confidence intervals (CIs) for the common intraclass correlation coefficient of several treatment groups. We consider the profile likelihood (PL)-based approach using the beta-binomial models and the approach based on the concept of generalized pivots using the ANOVA estimator and its asymptotic variance. We compare both approaches with a number of large sample procedures as well as both parametric and nonparametric bootstrap procedures in terms of coverage and expected CI length through a simulation study, and illustrate the methodology with two examples from biomedical fields. The results support the use of the PL-based CI as it holds the preassigned confidence level very well and overall gives a very competitive length.

  6. Neural network based load and price forecasting and confidence interval estimation in deregulated power markets

    Science.gov (United States)

    Zhang, Li

    With the deregulation of the electric power market in New England, an independent system operator (ISO) has been separated from the New England Power Pool (NEPOOL). The ISO provides a regional spot market, with bids on various electricity-related products and services submitted by utilities and independent power producers. A utility can bid on the spot market and buy or sell electricity via bilateral transactions. Good estimation of market clearing prices (MCP) will help utilities and independent power producers determine bidding and transaction strategies with low risks, and this is crucial for utilities to compete in the deregulated environment. MCP prediction, however, is difficult since bidding strategies used by participants are complicated and MCP is a non-stationary process. The main objective of this research is to provide efficient short-term load and MCP forecasting and corresponding confidence interval estimation methodologies. In this research, the complexity of load and MCP with other factors is investigated, and neural networks are used to model the complex relationship between input and output. With improved learning algorithm and on-line update features for load forecasting, a neural network based load forecaster was developed, and has been in daily industry use since summer 1998 with good performance. MCP is volatile because of the complexity of market behaviors. In practice, neural network based MCP predictors usually have a cascaded structure, as several key input factors need to be estimated first. In this research, the uncertainties involved in a cascaded neural network structure for MCP prediction are analyzed, and prediction distribution under the Bayesian framework is developed. A fast algorithm to evaluate the confidence intervals by using the memoryless Quasi-Newton method is also developed. The traditional back-propagation algorithm for neural network learning needs to be improved since MCP is a non-stationary process. The extended Kalman

  7. A NEW METHOD FOR CONSTRUCTING CONFIDENCE INTERVAL FOR CPM BASED ON FUZZY DATA

    Directory of Open Access Journals (Sweden)

    Bahram Sadeghpour Gildeh

    2011-06-01

    Full Text Available A measurement control system ensures that measuring equipment and measurement processes are fit for their intended use and its importance in achieving product quality objectives. In most real life applications, the observations are fuzzy. In some cases specification limits (SLs are not precise numbers and they are expressed in fuzzy terms, s o that the classical capability indices could not be applied. In this paper we obtain 100(1 - α% fuzzy confidence interval for C pm fuzzy process capability index, where instead of precise quality we have two membership functions for specification limits.

  8. Students' Conceptual Metaphors Influence Their Statistical Reasoning about Confidence Intervals. WCER Working Paper No. 2008-5

    Science.gov (United States)

    Grant, Timothy S.; Nathan, Mitchell J.

    2008-01-01

    Confidence intervals are beginning to play an increasing role in the reporting of research findings within the social and behavioral sciences and, consequently, are becoming more prevalent in beginning classes in statistics and research methods. Confidence intervals are an attractive means of conveying experimental results, as they contain a…

  9. Using learning curves and confidence intervals in a time study for the calculation of standard times

    Directory of Open Access Journals (Sweden)

    Mitzy Natalia Roncancio Avila

    2017-10-01

    Full Text Available Introduction: This article explores the use of learning curves and confidence intervals in a time study carry out in a scale assembly line during a laboratory practice at the University of La Salle. Objective: The objective of this research is to show the use of confidence intervals and learning curves for the identification of stable processes and subsequent standardization of timing Methodology: The methodology used consists in two phases: Analysis for the study of times and establishment of standard times; the first consist in the calculation of the number of cycles, depuration of atypical data and the use of the curves to determine the processes suitable for the standardization, and the second phase is the calculation of the standard times. Results: The analysis allowed to determine that is only possible to standardize two of the five processes of the system under study because of the variability of them. Conclusions: Given the research, is possible to conclude that a process should be standardized only if it presents a stable behavior respect to the normal rhythm of work, which is showed in the learning curve; otherwise, the process will obtain partial standard times.

  10. Two-Step Pseudomaximum Amplitude-Based Confidence Interval Estimation for Oscillometric Blood Pressure Measurements.

    Science.gov (United States)

    Lee, Soojeong; Jeon, Gwanggil; Kang, Seokhoon

    2015-01-01

    Blood pressure (BP) is an important vital sign to determine the health of an individual. Although the estimation of average arterial blood pressure using oscillometric methods is possible, there are no established methods for obtaining confidence intervals (CIs) for systolic blood pressure (SBP) and diastolic blood pressure (DBP). In this paper, we propose a two-step pseudomaximum amplitude (TSPMA) as a novel approach to obtain improved CIs of SBP and DBP using a double bootstrap approach. The weighted median (WM) filter is employed to reduce impulsive and Gaussian noises in the step of preprocessing. Application of the proposed method provides tighter CIs and smaller standard deviation of CIs than the pseudomaximum amplitude-envelope and maximum amplitude algorithms with Student's t-method.

  11. Two-Step Pseudomaximum Amplitude-Based Confidence Interval Estimation for Oscillometric Blood Pressure Measurements

    Directory of Open Access Journals (Sweden)

    Soojeong Lee

    2015-01-01

    Full Text Available Blood pressure (BP is an important vital sign to determine the health of an individual. Although the estimation of average arterial blood pressure using oscillometric methods is possible, there are no established methods for obtaining confidence intervals (CIs for systolic blood pressure (SBP and diastolic blood pressure (DBP. In this paper, we propose a two-step pseudomaximum amplitude (TSPMA as a novel approach to obtain improved CIs of SBP and DBP using a double bootstrap approach. The weighted median (WM filter is employed to reduce impulsive and Gaussian noises in the step of preprocessing. Application of the proposed method provides tighter CIs and smaller standard deviation of CIs than the pseudomaximum amplitude-envelope and maximum amplitude algorithms with Student’s t-method.

  12. Sample size calculations for pilot randomized trials: a confidence interval approach.

    Science.gov (United States)

    Cocks, Kim; Torgerson, David J

    2013-02-01

    To describe a method using confidence intervals (CIs) to estimate the sample size for a pilot randomized trial. Using one-sided CIs and the estimated effect size that would be sought in a large trial, we calculated the sample size needed for pilot trials. Using an 80% one-sided CI, we estimated that a pilot trial should have at least 9% of the sample size of the main planned trial. Using the estimated effect size difference for the main trial and using a one-sided CI, this allows us to calculate a sample size for a pilot trial, which will make its results more useful than at present. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Statistical variability and confidence intervals for planar dose QA pass rates

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Daniel W.; Nelms, Benjamin E.; Attwood, Kristopher; Kumaraswamy, Lalith; Podgorsak, Matthew B. [Department of Physics, State University of New York at Buffalo, Buffalo, New York 14260 (United States) and Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Department of Biostatistics, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Molecular and Cellular Biophysics and Biochemistry, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States) and Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14214 (United States)

    2011-11-15

    Purpose: The most common metric for comparing measured to calculated dose, such as for pretreatment quality assurance of intensity-modulated photon fields, is a pass rate (%) generated using percent difference (%Diff), distance-to-agreement (DTA), or some combination of the two (e.g., gamma evaluation). For many dosimeters, the grid of analyzed points corresponds to an array with a low areal density of point detectors. In these cases, the pass rates for any given comparison criteria are not absolute but exhibit statistical variability that is a function, in part, on the detector sampling geometry. In this work, the authors analyze the statistics of various methods commonly used to calculate pass rates and propose methods for establishing confidence intervals for pass rates obtained with low-density arrays. Methods: Dose planes were acquired for 25 prostate and 79 head and neck intensity-modulated fields via diode array and electronic portal imaging device (EPID), and matching calculated dose planes were created via a commercial treatment planning system. Pass rates for each dose plane pair (both centered to the beam central axis) were calculated with several common comparison methods: %Diff/DTA composite analysis and gamma evaluation, using absolute dose comparison with both local and global normalization. Specialized software was designed to selectively sample the measured EPID response (very high data density) down to discrete points to simulate low-density measurements. The software was used to realign the simulated detector grid at many simulated positions with respect to the beam central axis, thereby altering the low-density sampled grid. Simulations were repeated with 100 positional iterations using a 1 detector/cm{sup 2} uniform grid, a 2 detector/cm{sup 2} uniform grid, and similar random detector grids. For each simulation, %/DTA composite pass rates were calculated with various %Diff/DTA criteria and for both local and global %Diff normalization

  14. The confidence interval of allelic odds ratios under the Hardy-Weinberg disequilibrium.

    Science.gov (United States)

    Sato, Yasunori; Suganami, Hideki; Hamada, Chikuma; Yoshimura, Isao; Sakamoto, Hiromi; Yoshida, Teruhiko; Yoshimura, Kimio

    2006-01-01

    In single nucleotide polymorphism (SNP) data analysis, the allelic odds ratio and its confidence interval (CI) are usually used to evaluate the association between disease and alleles at each SNP. The usual formula for calculating the CI of the allelic odds ratio based on the Hardy-Weinberg equilibrium (HWE) may, however, lead to errors beyond the control assured by the nominal confidence level if HWE is not true. We therefore present a generalized formula for CI that does not assume HWE. CIs calculated by this generalized formula are likely to be wider than those by the usual method if the Hardy-Weinberg disequilibrium (HWD) is toward a relative deficiency of the heterozygotes (fixation index greater than 0), whereas they are likely to be narrower if HWD is toward a relative excess of the heterozygotes (fixation index less than 0). A simulation experiment to examine the influence of the generalization was performed for the case where 2% of SNPs had a fixation index greater than 0. The result revealed that the generalized method slightly decreased the mean number of falsely detected SNPs.

  15. Uncertainty in population growth rates: determining confidence intervals from point estimates of parameters.

    Directory of Open Access Journals (Sweden)

    Eleanor S Devenish Nelson

    Full Text Available BACKGROUND: Demographic models are widely used in conservation and management, and their parameterisation often relies on data collected for other purposes. When underlying data lack clear indications of associated uncertainty, modellers often fail to account for that uncertainty in model outputs, such as estimates of population growth. METHODOLOGY/PRINCIPAL FINDINGS: We applied a likelihood approach to infer uncertainty retrospectively from point estimates of vital rates. Combining this with resampling techniques and projection modelling, we show that confidence intervals for population growth estimates are easy to derive. We used similar techniques to examine the effects of sample size on uncertainty. Our approach is illustrated using data on the red fox, Vulpes vulpes, a predator of ecological and cultural importance, and the most widespread extant terrestrial mammal. We show that uncertainty surrounding estimated population growth rates can be high, even for relatively well-studied populations. Halving that uncertainty typically requires a quadrupling of sampling effort. CONCLUSIONS/SIGNIFICANCE: Our results compel caution when comparing demographic trends between populations without accounting for uncertainty. Our methods will be widely applicable to demographic studies of many species.

  16. Confidence intervals in within-subject designs: A simpler solution to Loftus and Masson's method

    Directory of Open Access Journals (Sweden)

    Denis Cousineau

    2005-09-01

    Full Text Available Within-subject ANOVAs are a powerful tool to analyze data because the variance associated to differences between the participants is removed from the analysis. Hence, small differences, when present for most of the participants, can be significant even when the participants are very different from one another. Yet, graphs showing standard error or confidence interval bars are misleading since these bars include the between-subject variability. Loftus and Masson (1994 noticed this fact and proposed an alternate method to compute the error bars. However, i their approach requires that the ANOVA be performed first, which is paradoxical since a graph is an aid to decide whether to perform analyses or not; ii their method provides a single error bar for all the conditions, masking information such as the heterogeneity of variances across conditions; iii the method proposed is difficult to implement in commonly-used graphing software. Here we propose a simpler alternative and show how it can be implemented in SPSS.

  17. Reporting of statistical results in prosthodontic and implantology journals: p values or confidence intervals?

    Science.gov (United States)

    Kloukos, Dimitrios; Papageorgiou, Spyridon N; Fleming, Padhraig S; Petridis, Haralampos; Pandis, Nikolaos

    2014-01-01

    Confidence intervals (CIs) are integral to the interpretation of the precision and clinical relevance of research findings. The aim of this study was to ascertain the frequency of reporting of CIs in leading prosthodontic and dental implantology journals and to explore possible factors associated with improved reporting. Thirty issues of nine journals in prosthodontics and implant dentistry were accessed, covering the years 2005 to 2012: The Journal of Prosthetic Dentistry, Journal of Oral Rehabilitation, The International Journal of Prosthodontics, The International Journal of Periodontics & Restorative Dentistry, Clinical Oral Implants Research, Clinical Implant Dentistry and Related Research, The International Journal of Oral & Maxillofacial Implants, Implant Dentistry, and Journal of Dentistry. Articles were screened and the reporting of CIs and P values recorded. Other information including study design, region of authorship, involvement of methodologists, and ethical approval was also obtained. Univariable and multivariable logistic regression was used to identify characteristics associated with reporting of CIs. Interrater agreement for the data extraction performed was excellent (kappa = 0.88; 95% CI: 0.87 to 0.89). CI reporting was limited, with mean reporting across journals of 14%. CI reporting was associated with journal type, study design, and involvement of a methodologist or statistician. Reporting of CI in implant dentistry and prosthodontic journals requires improvement. Improved reporting will aid appraisal of the clinical relevance of research findings by providing a range of values within which the effect size lies, thus giving the end user the opportunity to interpret the results in relation to clinical practice.

  18. Reliability and Confidence Interval Analysis of a CMC Turbine Stator Vane

    Science.gov (United States)

    Murthy, Pappu L. N.; Gyekenyesi, John P.; Mital, Subodh K.

    2008-01-01

    an economical manner. The methods to accurately determine the service life of an engine component with associated variability have become increasingly difficult. This results, in part, from the complex missions which are now routinely considered during the design process. These missions include large variations of multi-axial stresses and temperatures experienced by critical engine parts. There is a need for a convenient design tool that can accommodate various loading conditions induced by engine operating environments, and material data with their associated uncertainties to estimate the minimum predicted life of a structural component. A probabilistic composite micromechanics technique in combination with woven composite micromechanics, structural analysis and Fast Probability Integration (FPI) techniques has been used to evaluate the maximum stress and its probabilistic distribution in a CMC turbine stator vane. Furthermore, input variables causing scatter are identified and ranked based upon their sensitivity magnitude. Since the measured data for the ceramic matrix composite properties is very limited, obtaining a probabilistic distribution with their corresponding parameters is difficult. In case of limited data, confidence bounds are essential to quantify the uncertainty associated with the distribution. Usually 90 and 95% confidence intervals are computed for material properties. Failure properties are then computed with the confidence bounds. Best estimates and the confidence bounds on the best estimate of the cumulative probability function for R-S (strength - stress) are plotted. The methodologies and the results from these analyses will be discussed in the presentation.

  19. Existence test for asynchronous interval iterations

    DEFF Research Database (Denmark)

    Madsen, Kaj; Caprani, O.; Stauning, Ole

    1997-01-01

    In the search for regions that contain fixed points ofa real function of several variables, tests based on interval calculationscan be used to establish existence ornon-existence of fixed points in regions that are examined in the course ofthe search. The search can e.g. be performed...... as a synchronous (sequential) interval iteration:In each iteration step all components of the iterate are calculatedbased on the previous iterate. In this case it is straight forward to base simple interval existence and non-existencetests on the calculations done in each step of the iteration. The search can also...... be performed as an asynchronous (parallel) iteration: Only a few components are changed in each stepand this calculation is in general based on components from differentprevious iterates. For the asynchronous iteration it turns out thatsimple tests of existence and non-existence can be based...

  20. Algorithmic identification of discrepancies between published ratios and their reported confidence intervals and p-values.

    Science.gov (United States)

    Georgescu, Constantin; Wren, Jonathan D

    2017-12-22

    Studies, mostly from the operations/management literature, have shown that the rate of human error increases with task complexity. What is not known is how many errors make it into the published literature, given that they must slip by peer-review. By identifying paired, dependent values within text for reported calculations of varying complexity, we can identify discrepancies, quantify error rates and identify mitigating factors. We extracted statistical ratios from MEDLINE abstracts (Hazard Ratio, Odds Ratio, Relative Risk), their 95% confidence intervals (CIs), and their p-values. We re-calculated the ratios and p-values using the reported CIs. For comparison, we also extracted percent-ratio pairs, one of the simplest calculation tasks. Over 486,000 published values were found and analyzed for discrepancies, allowing for rounding and significant figures. Per reported item, discrepancies were less frequent in percent-ratio calculations (2.7%) than in ratio-CI and p-value calculations (5.6% to 7.5%), and smaller discrepancies were more frequent than large ones. Systematic discrepancies (multiple incorrect calculations of the same type) were higher for more complex tasks (14.3%) than simple ones (6.7%). Discrepancy rates decreased with increasing journal impact factor (JIF) and increasing number of authors, but with diminishing returns and JIF accounting for most of the effect. Approximately 87% of the 81,937 extracted p-values were ≤ 0.05. Using a simple, yet accurate, approach to identifying paired values within text, we offer the first quantitative evaluation of published error frequencies within these types of calculations. N/A. Jonathan-Wren@OMRF.org; jdwren@gmail.com. Available online.

  1. Test Anxiety Reduction and Confidence Training: A Replication

    Science.gov (United States)

    Bowman, Noah; Driscoll, Richard

    2013-01-01

    This study was undertaken to replicate prior research in which a brief counter-conditioning and confidence training program was found to reduce anxiety and raise test scores. First-semester college students were screened with the Westside Test Anxiety Scale, and the 25 identified as having high or moderately-high anxiety were randomly divided…

  2. A comparison of confidence interval methods for the intraclass correlation coefficient in community-based cluster randomization trials with a binary outcome.

    Science.gov (United States)

    Braschel, Melissa C; Svec, Ivana; Darlington, Gerarda A; Donner, Allan

    2016-04-01

    Many investigators rely on previously published point estimates of the intraclass correlation coefficient rather than on their associated confidence intervals to determine the required size of a newly planned cluster randomized trial. Although confidence interval methods for the intraclass correlation coefficient that can be applied to community-based trials have been developed for a continuous outcome variable, fewer methods exist for a binary outcome variable. The aim of this study is to evaluate confidence interval methods for the intraclass correlation coefficient applied to binary outcomes in community intervention trials enrolling a small number of large clusters. Existing methods for confidence interval construction are examined and compared to a new ad hoc approach based on dividing clusters into a large number of smaller sub-clusters and subsequently applying existing methods to the resulting data. Monte Carlo simulation is used to assess the width and coverage of confidence intervals for the intraclass correlation coefficient based on Smith's large sample approximation of the standard error of the one-way analysis of variance estimator, an inverted modified Wald test for the Fleiss-Cuzick estimator, and intervals constructed using a bootstrap-t applied to a variance-stabilizing transformation of the intraclass correlation coefficient estimate. In addition, a new approach is applied in which clusters are randomly divided into a large number of smaller sub-clusters with the same methods applied to these data (with the exception of the bootstrap-t interval, which assumes large cluster sizes). These methods are also applied to a cluster randomized trial on adolescent tobacco use for illustration. When applied to a binary outcome variable in a small number of large clusters, existing confidence interval methods for the intraclass correlation coefficient provide poor coverage. However, confidence intervals constructed using the new approach combined with Smith

  3. Simulation data for an estimation of the maximum theoretical value and confidence interval for the correlation coefficient.

    Science.gov (United States)

    Rocco, Paolo; Cilurzo, Francesco; Minghetti, Paola; Vistoli, Giulio; Pedretti, Alessandro

    2017-10-01

    The data presented in this article are related to the article titled "Molecular Dynamics as a tool for in silico screening of skin permeability" (Rocco et al., 2017) [1]. Knowledge of the confidence interval and maximum theoretical value of the correlation coefficient r can prove useful to estimate the reliability of developed predictive models, in particular when there is great variability in compiled experimental datasets. In this Data in Brief article, data from purposely designed numerical simulations are presented to show how much the maximum r value is worsened by increasing the data uncertainty. The corresponding confidence interval of r is determined by using the Fisher r→Z transform.

  4. Data Transformation for Confidence Interval Improvement: An Application to the Estimation of Stress-Strength Model Reliability

    Directory of Open Access Journals (Sweden)

    Alessandro Barbiero

    2014-01-01

    Full Text Available In many statistical applications, it is often necessary to obtain an interval estimate for an unknown proportion or probability or, more generally, for a parameter whose natural space is the unit interval. The customary approximate two-sided confidence interval for such a parameter, based on some version of the central limit theorem, is known to be unsatisfactory when its true value is close to zero or one or when the sample size is small. A possible way to tackle this issue is the transformation of the data through a proper function that is able to make the approximation to the normal distribution less coarse. In this paper, we study the application of several of these transformations to the context of the estimation of the reliability parameter for stress-strength models, with a special focus on Poisson distribution. From this work, some practical hints emerge on which transformation may more efficiently improve standard confidence intervals in which scenarios.

  5. Confidence Intervals for the Probability of Superiority Effect Size Measure and the Area under a Receiver Operating Characteristic Curve

    Science.gov (United States)

    Ruscio, John; Mullen, Tara

    2012-01-01

    It is good scientific practice to the report an appropriate estimate of effect size and a confidence interval (CI) to indicate the precision with which a population effect was estimated. For comparisons of 2 independent groups, a probability-based effect size estimator (A) that is equal to the area under a receiver operating characteristic curve…

  6. Confidence Intervals for Effect Sizes: Compliance and Clinical Significance in the "Journal of Consulting and Clinical Psychology"

    Science.gov (United States)

    Odgaard, Eric C.; Fowler, Robert L.

    2010-01-01

    Objective: In 2005, the "Journal of Consulting and Clinical Psychology" ("JCCP") became the first American Psychological Association (APA) journal to require statistical measures of clinical significance, plus effect sizes (ESs) and associated confidence intervals (CIs), for primary outcomes (La Greca, 2005). As this represents the single largest…

  7. Step-up related simultaneous confidence intervals for MCC and MCB.

    Science.gov (United States)

    Finner, Helmut; Strassburger, Klaus

    2007-02-01

    The derivation of compatible confidence bounds related to stepwise decision procedures is a serious issue. Especially the derivation of step-up related bounds is rather complex. In this article we consider (one-sided) multiple comparisons with a control (MCC) and multiple comparisons with the best (MCB) with the aim of establishing delta-equivalence to the best and derive step-up related confidence bounds by applying the projection method proposed in Finner and Strassburger (2006). Some examples illustrate the resulting procedures.

  8. Common pitfalls in statistical analysis: "P" values, statistical significance and confidence intervals

    Directory of Open Access Journals (Sweden)

    Priya Ranganathan

    2015-01-01

    Full Text Available In the second part of a series on pitfalls in statistical analysis, we look at various ways in which a statistically significant study result can be expressed. We debunk some of the myths regarding the ′P′ value, explain the importance of ′confidence intervals′ and clarify the importance of including both values in a paper

  9. Confidence intervals for effect sizes: compliance and clinical significance in the Journal of Consulting and clinical Psychology.

    Science.gov (United States)

    Odgaard, Eric C; Fowler, Robert L

    2010-06-01

    In 2005, the Journal of Consulting and Clinical Psychology (JCCP) became the first American Psychological Association (APA) journal to require statistical measures of clinical significance, plus effect sizes (ESs) and associated confidence intervals (CIs), for primary outcomes (La Greca, 2005). As this represents the single largest editorial effort to improve statistical reporting practices in any APA journal in at least a decade, in this article we investigate the efficacy of that change. All intervention studies published in JCCP in 2003, 2004, 2007, and 2008 were reviewed. Each article was coded for method of clinical significance, type of ES, and type of associated CI, broken down by statistical test (F, t, chi-square, r/R(2), and multivariate modeling). By 2008, clinical significance compliance was 75% (up from 31%), with 94% of studies reporting some measure of ES (reporting improved for individual statistical tests ranging from eta(2) = .05 to .17, with reasonable CIs). Reporting of CIs for ESs also improved, although only to 40%. Also, the vast majority of reported CIs used approximations, which become progressively less accurate for smaller sample sizes and larger ESs (cf. Algina & Kessleman, 2003). Changes are near asymptote for ESs and clinical significance, but CIs lag behind. As CIs for ESs are required for primary outcomes, we show how to compute CIs for the vast majority of ESs reported in JCCP, with an example of how to use CIs for ESs as a method to assess clinical significance.

  10. Monte Carlo simulation of parameter confidence intervals for non-linear regression analysis of biological data using Microsoft Excel.

    Science.gov (United States)

    Lambert, Ronald J W; Mytilinaios, Ioannis; Maitland, Luke; Brown, Angus M

    2012-08-01

    This study describes a method to obtain parameter confidence intervals from the fitting of non-linear functions to experimental data, using the SOLVER and Analysis ToolPaK Add-In of the Microsoft Excel spreadsheet. Previously we have shown that Excel can fit complex multiple functions to biological data, obtaining values equivalent to those returned by more specialized statistical or mathematical software. However, a disadvantage of using the Excel method was the inability to return confidence intervals for the computed parameters or the correlations between them. Using a simple Monte-Carlo procedure within the Excel spreadsheet (without recourse to programming), SOLVER can provide parameter estimates (up to 200 at a time) for multiple 'virtual' data sets, from which the required confidence intervals and correlation coefficients can be obtained. The general utility of the method is exemplified by applying it to the analysis of the growth of Listeria monocytogenes, the growth inhibition of Pseudomonas aeruginosa by chlorhexidine and the further analysis of the electrophysiological data from the compound action potential of the rodent optic nerve. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  11. Technical Report: Algorithm and Implementation for Quasispecies Abundance Inference with Confidence Intervals from Metagenomic Sequence Data

    Energy Technology Data Exchange (ETDEWEB)

    McLoughlin, Kevin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-01-11

    This report describes the design and implementation of an algorithm for estimating relative microbial abundances, together with confidence limits, using data from metagenomic DNA sequencing. For the background behind this project and a detailed discussion of our modeling approach for metagenomic data, we refer the reader to our earlier technical report, dated March 4, 2014. Briefly, we described a fully Bayesian generative model for paired-end sequence read data, incorporating the effects of the relative abundances, the distribution of sequence fragment lengths, fragment position bias, sequencing errors and variations between the sampled genomes and the nearest reference genomes. A distinctive feature of our modeling approach is the use of a Chinese restaurant process (CRP) to describe the selection of genomes to be sampled, and thus the relative abundances. The CRP component is desirable for fitting abundances to reads that may map ambiguously to multiple targets, because it naturally leads to sparse solutions that select the best representative from each set of nearly equivalent genomes.

  12. Technical Report: Benchmarking for Quasispecies Abundance Inference with Confidence Intervals from Metagenomic Sequence Data

    Energy Technology Data Exchange (ETDEWEB)

    McLoughlin, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-01-22

    The software application “MetaQuant” was developed by our group at Lawrence Livermore National Laboratory (LLNL). It is designed to profile microbial populations in a sample using data from whole-genome shotgun (WGS) metagenomic DNA sequencing. Several other metagenomic profiling applications have been described in the literature. We ran a series of benchmark tests to compare the performance of MetaQuant against that of a few existing profiling tools, using real and simulated sequence datasets. This report describes our benchmarking procedure and results.

  13. Experimental optimization of the number of blocks by means of algorithms parameterized by confidence interval in popcorn breeding.

    Science.gov (United States)

    Paula, T O M; Marinho, C D; Amaral Júnior, A T; Peternelli, L A; Gonçalves, L S A

    2013-06-27

    The objective of this study was to determine the optimal number of repetitions to be used in competition trials of popcorn traits related to production and quality, including grain yield and expansion capacity. The experiments were conducted in 3 environments representative of the north and northwest regions of the State of Rio de Janeiro with 10 Brazilian genotypes of popcorn, consisting by 4 commercial hybrids (IAC 112, IAC 125, Zélia, and Jade), 4 improved varieties (BRS Ângela, UFVM-2 Barão de Viçosa, Beija-flor, and Viçosa) and 2 experimental populations (UNB2U-C3 and UNB2U-C4). The experimental design utilized was a randomized complete block design with 7 repetitions. The Bootstrap method was employed to obtain samples of all of the possible combinations within the 7 blocks. Subsequently, the confidence intervals of the parameters of interest were calculated for all simulated data sets. The optimal number of repetition for all of the traits was considered when all of the estimates of the parameters in question were encountered within the confidence interval. The estimates of the number of repetitions varied according to the parameter estimated, variable evaluated, and environment cultivated, ranging from 2 to 7. It is believed that only the expansion capacity traits in the Colégio Agrícola environment (for residual variance and coefficient of variation), and number of ears per plot, in the Itaocara environment (for coefficient of variation) needed 7 repetitions to fall within the confidence interval. Thus, for the 3 studies conducted, we can conclude that 6 repetitions are optimal for obtaining high experimental precision.

  14. Including test errors in evaluating surveillance test intervals

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I.S.; Samanta, P.K. [Brookhaven National Lab., Upton, NY (United States); Martorell, S. [Universidad Politecnica de Valencia (Spain); Vesely, W.E. [Science Applications International Corp., San Diego, CA (United States)

    1991-12-31

    Technical Specifications require surveillance testing to assure that the standby systems important to safety will start and perform their intended functions in the event of plant abnormality. However, as evidenced by operating experience, the surveillance tests may be adversely impact safety because of their undesirable side effects, such as initiation of plant transients during testing or wearing-out of safety systems due to testing. This paper first defines the concerns, i.e., the potential adverse effects of surveillance testing, from a risk perspective. Then, we present a methodology to evaluate the risk impact of those adverse effects, focusing on two important kinds of adverse impacts of surveillance testing: (1) risk impact of test-caused trips and (2) risk impact of test-caused equipment wear. The quantitative risk methodology is demonstrated with several surveillance tests conducted at boiling water reactors, such as the tests of the main steam isolation valves, the turbine overspeed protection system, and the emergency diesel generators. We present the results of the risk-effectiveness evaluation of surveillance test intervals, which compares the adverse risk impact with the beneficial risk impact of testing from potential failure detection, along with insights from sensitivity studies.

  15. An approach for calculating a confidence interval from a single aquatic sample for monitoring hydrophobic organic contaminants.

    Science.gov (United States)

    Matzke, Melissa M; Allan, Sarah E; Anderson, Kim A; Waters, Katrina M

    2012-12-01

    The use of passive sampling devices (PSDs) for monitoring hydrophobic organic contaminants in aquatic environments can entail logistical constraints that often limit a comprehensive statistical sampling plan, thus resulting in a restricted number of samples. The present study demonstrates an approach for using the results of a pilot study designed to estimate sampling variability, which in turn can be used as variance estimates for confidence intervals for future n = 1 PSD samples of the same aquatic system. Sets of three to five PSDs were deployed in the Portland Harbor Superfund site for three sampling periods over the course of two years. The PSD filters were extracted and, as a composite sample, analyzed for 33 polycyclic aromatic hydrocarbon compounds. The between-sample and within-sample variances were calculated to characterize sources of variability in the environment and sampling methodology. A method for calculating a statistically reliable and defensible confidence interval for the mean of a single aquatic passive sampler observation (i.e., n = 1) using an estimate of sample variance derived from a pilot study is presented. Coverage probabilities are explored over a range of variance values using a Monte Carlo simulation. Copyright © 2012 SETAC.

  16. Fast bootstrapping-based estimation of confidence intervals of expression levels and differential expression from RNA-Seq data.

    Science.gov (United States)

    Mandric, Igor; Temate-Tiagueu, Yvette; Shcheglova, Tatiana; Al Seesi, Sahar; Zelikovsky, Alex; Mandoiu, Ion I

    2017-10-15

    This note presents IsoEM2 and IsoDE2, new versions with enhanced features and faster runtime of the IsoEM and IsoDE packages for expression level estimation and differential expression. IsoEM2 estimates fragments per kilobase million (FPKM) and transcript per million (TPM) levels for genes and isoforms with confidence intervals through bootstrapping, while IsoDE2 performs differential expression analysis using the bootstrap samples generated by IsoEM2. Both tools are available with a command line interface as well as a graphical user interface (GUI) through wrappers for the Galaxy platform. The source code of this software suite is available at https://github.com/mandricigor/isoem2. The Galaxy wrappers are available at https://toolshed.g2.bx.psu.edu/view/saharlcc/isoem2_isode2/. imandric1@student.gsu.edu or ion@engr.uconn.edu. Supplementary data are available at Bioinformatics online.

  17. Correction of confidence intervals in excess relative risk models using Monte Carlo dosimetry systems with shared errors.

    Directory of Open Access Journals (Sweden)

    Zhuo Zhang

    Full Text Available In epidemiological studies, exposures of interest are often measured with uncertainties, which may be independent or correlated. Independent errors can often be characterized relatively easily while correlated measurement errors have shared and hierarchical components that complicate the description of their structure. For some important studies, Monte Carlo dosimetry systems that provide multiple realizations of exposure estimates have been used to represent such complex error structures. While the effects of independent measurement errors on parameter estimation and methods to correct these effects have been studied comprehensively in the epidemiological literature, the literature on the effects of correlated errors, and associated correction methods is much more sparse. In this paper, we implement a novel method that calculates corrected confidence intervals based on the approximate asymptotic distribution of parameter estimates in linear excess relative risk (ERR models. These models are widely used in survival analysis, particularly in radiation epidemiology. Specifically, for the dose effect estimate of interest (increase in relative risk per unit dose, a mixture distribution consisting of a normal and a lognormal component is applied. This choice of asymptotic approximation guarantees that corrected confidence intervals will always be bounded, a result which does not hold under a normal approximation. A simulation study was conducted to evaluate the proposed method in survival analysis using a realistic ERR model. We used both simulated Monte Carlo dosimetry systems (MCDS and actual dose histories from the Mayak Worker Dosimetry System 2013, a MCDS for plutonium exposures in the Mayak Worker Cohort. Results show our proposed methods provide much improved coverage probabilities for the dose effect parameter, and noticeable improvements for other model parameters.

  18. A comparison of confidence interval methods for the concordance correlation coefficient and intraclass correlation coefficient with small number of raters.

    Science.gov (United States)

    Feng, Dai; Svetnik, Vladimir; Coimbra, Alexandre; Baumgartner, Richard

    2014-01-01

    The intraclass correlation coefficient (ICC) with fixed raters or, equivalently, the concordance correlation coefficient (CCC) for continuous outcomes is a widely accepted aggregate index of agreement in settings with small number of raters. Quantifying the precision of the CCC by constructing its confidence interval (CI) is important in early drug development applications, in particular in qualification of biomarker platforms. In recent years, there have been several new methods proposed for construction of CIs for the CCC, but their comprehensive comparison has not been attempted. The methods consisted of the delta method and jackknifing with and without Fisher's Z-transformation, respectively, and Bayesian methods with vague priors. In this study, we carried out a simulation study, with data simulated from multivariate normal as well as heavier tailed distribution (t-distribution with 5 degrees of freedom), to compare the state-of-the-art methods for assigning CI to the CCC. When the data are normally distributed, the jackknifing with Fisher's Z-transformation (JZ) tended to provide superior coverage and the difference between it and the closest competitor, the Bayesian method with the Jeffreys prior was in general minimal. For the nonnormal data, the jackknife methods, especially the JZ method, provided the coverage probabilities closest to the nominal in contrast to the others which yielded overly liberal coverage. Approaches based upon the delta method and Bayesian method with conjugate prior generally provided slightly narrower intervals and larger lower bounds than others, though this was offset by their poor coverage. Finally, we illustrated the utility of the CIs for the CCC in an example of a wake after sleep onset (WASO) biomarker, which is frequently used in clinical sleep studies of drugs for treatment of insomnia.

  19. Confidence bounds and hypothesis tests for normal distribution coefficients of variation

    Science.gov (United States)

    Steve Verrill; Richard A. Johnson

    2007-01-01

    For normally distributed populations, we obtain confidence bounds on a ratio of two coefficients of variation, provide a test for the equality of k coefficients of variation, and provide confidence bounds on a coefficient of variation shared by k populations.

  20. Confidence-weighted testing: a descriptive study of Japanese nursing students.

    Science.gov (United States)

    Aoyama, Michiyo; Tamura, Yumi; Ishikawa, Yuichi; Yada, Mamiko; Miyawaki, Ikuko

    2013-12-01

    Nurses' lack of self-confidence in their own nursing skills is one of the main reasons that novice nurses leave the profession in Japan. Nursing education must help students gain self-confidence in their nursing skills in order to allow more novice nurses to stay in their profession. In this study, we evaluated whether confidence-weighted testing feedback actually improves students' self-confidence in their basic nursing skills. Confidence-weighted testing, which provides quantifiable results, might allow students to objectively assess their skill-related self-confidence. Sixty-seven first-year nursing students took two confidence-rating examinations on the knowledge and practical skills related to pulse and blood pressure measurement of immobile patients. Feedback was given to each participant after the first examination. After the first examination with confidence-weighted testing feedback, students showed higher levels of self-confidence in their practical skills, but not in knowledge. The improvement of self-confidence in practical skills suggests that there is still room for improvement in confidence-weighted testing feedback in knowledge. Further research is required to identify more effective feedback methods to improve students' self-confidence levels in knowledge using the results of confidence-weighted testing. © 2013 Wiley Publishing Asia Pty Ltd.

  1. Using Confidence Interval-Based Estimation of Relevance to Select Social-Cognitive Determinants for Behavior Change Interventions

    Directory of Open Access Journals (Sweden)

    Rik Crutzen

    2017-07-01

    Full Text Available When developing an intervention aimed at behavior change, one of the crucial steps in the development process is to select the most relevant social-cognitive determinants. These determinants can be seen as the buttons one needs to push to establish behavior change. Insight into these determinants is needed to select behavior change methods (i.e., general behavior change techniques that are applied in an intervention in the development process. Therefore, a study on determinants is often conducted as formative research in the intervention development process. Ideally, all relevant determinants identified in such a study are addressed by an intervention. However, when developing a behavior change intervention, there are limits in terms of, for example, resources available for intervention development and the amount of content that participants of an intervention can be exposed to. Hence, it is important to select those determinants that are most relevant to the target behavior as these determinants should be addressed in an intervention. The aim of the current paper is to introduce a novel approach to select the most relevant social-cognitive determinants and use them in intervention development. This approach is based on visualization of confidence intervals for the means and correlation coefficients for all determinants simultaneously. This visualization facilitates comparison, which is necessary when making selections. By means of a case study on the determinants of using a high dose of 3,4-methylenedioxymethamphetamine (commonly known as ecstasy, we illustrate this approach. We provide a freely available tool to facilitate the analyses needed in this approach.

  2. Bootstrap Signal-to-Noise Confidence Intervals: An Objective Method for Subject Exclusion and Quality Control in ERP Studies

    Directory of Open Access Journals (Sweden)

    Nathan A Parks

    2016-02-01

    Full Text Available Analysis of event-related potential (ERP data includes several steps to ensure that ERPs meet an appropriate level of signal quality. One such step, subject exclusion, rejects subject data if ERP waveforms fail to meet an appropriate level of signal quality. Subject exclusion is an important quality control step in the ERP analysis pipeline as it ensures that statistical inference is based only upon those subjects exhibiting clear evoked brain responses. This critical quality control step is most often performed simply through visual inspection of subject-level ERPs by investigators. Such an approach is qualitative, subjective, and susceptible to investigator bias, as there are no standards as to what constitutes an ERP of sufficient signal quality. Here, we describe a standardized and objective method for quantifying waveform quality in individual subjects and establishing criteria for subject exclusion. The approach uses bootstrap resampling of ERP waveforms (from a pool of all available trials to compute a signal-to-noise ratio confidence interval (SNR-CI for individual subject waveforms. The lower bound of this SNR-CI (SNRLB yields an effective and objective measure of signal quality as it ensures that ERP waveforms statistically exceed a desired signal-to-noise criterion. SNRLB provides a quantifiable metric of individual subject ERP quality and eliminates the need for subjective evaluation of waveform quality by the investigator. We detail the SNR-CI methodology, establish the efficacy of employing this approach with Monte Carlo simulations, and demonstrate its utility in practice when applied to ERP datasets.

  3. Using Confidence Interval-Based Estimation of Relevance to Select Social-Cognitive Determinants for Behavior Change Interventions.

    Science.gov (United States)

    Crutzen, Rik; Peters, Gjalt-Jorn Ygram; Noijen, Judith

    2017-01-01

    When developing an intervention aimed at behavior change, one of the crucial steps in the development process is to select the most relevant social-cognitive determinants. These determinants can be seen as the buttons one needs to push to establish behavior change. Insight into these determinants is needed to select behavior change methods (i.e., general behavior change techniques that are applied in an intervention) in the development process. Therefore, a study on determinants is often conducted as formative research in the intervention development process. Ideally, all relevant determinants identified in such a study are addressed by an intervention. However, when developing a behavior change intervention, there are limits in terms of, for example, resources available for intervention development and the amount of content that participants of an intervention can be exposed to. Hence, it is important to select those determinants that are most relevant to the target behavior as these determinants should be addressed in an intervention. The aim of the current paper is to introduce a novel approach to select the most relevant social-cognitive determinants and use them in intervention development. This approach is based on visualization of confidence intervals for the means and correlation coefficients for all determinants simultaneously. This visualization facilitates comparison, which is necessary when making selections. By means of a case study on the determinants of using a high dose of 3,4-methylenedioxymethamphetamine (commonly known as ecstasy), we illustrate this approach. We provide a freely available tool to facilitate the analyses needed in this approach.

  4. Bootstrap Signal-to-Noise Confidence Intervals: An Objective Method for Subject Exclusion and Quality Control in ERP Studies

    Science.gov (United States)

    Parks, Nathan A.; Gannon, Matthew A.; Long, Stephanie M.; Young, Madeleine E.

    2016-01-01

    Analysis of event-related potential (ERP) data includes several steps to ensure that ERPs meet an appropriate level of signal quality. One such step, subject exclusion, rejects subject data if ERP waveforms fail to meet an appropriate level of signal quality. Subject exclusion is an important quality control step in the ERP analysis pipeline as it ensures that statistical inference is based only upon those subjects exhibiting clear evoked brain responses. This critical quality control step is most often performed simply through visual inspection of subject-level ERPs by investigators. Such an approach is qualitative, subjective, and susceptible to investigator bias, as there are no standards as to what constitutes an ERP of sufficient signal quality. Here, we describe a standardized and objective method for quantifying waveform quality in individual subjects and establishing criteria for subject exclusion. The approach uses bootstrap resampling of ERP waveforms (from a pool of all available trials) to compute a signal-to-noise ratio confidence interval (SNR-CI) for individual subject waveforms. The lower bound of this SNR-CI (SNRLB) yields an effective and objective measure of signal quality as it ensures that ERP waveforms statistically exceed a desired signal-to-noise criterion. SNRLB provides a quantifiable metric of individual subject ERP quality and eliminates the need for subjective evaluation of waveform quality by the investigator. We detail the SNR-CI methodology, establish the efficacy of employing this approach with Monte Carlo simulations, and demonstrate its utility in practice when applied to ERP datasets. PMID:26903849

  5. The effect of success probability on test economy and self-confidence in computerized adaptive tests

    Directory of Open Access Journals (Sweden)

    JOACHIM HÄUSLER

    2008-03-01

    Full Text Available Recent research on the psychological effects of different design decisions in computerized adaptive tests indicates that the maximum-information item selection rule fails to optimize respondents’ test-taking motivation. While several recent studies have investigated psychological reactions to computerized adaptive tests using a consistently higher base success rate, little research has so far been conducted on the psychometric (primarily test reliability and bias and psychological effects (e.g. test-taking motivation, self-confidence of using mixtures of highly informative (p = .50 and easier items (p = .80 in the item selection process. The present paper thus compares these modifications to item selection with a classical maximum-information algorithm. In a simulation study the effect of the different item selection algorithms on measurement precision and bias in the person parameter estimates is evaluated. To do so, the item pool of the Lexical Knowledge Test, measuring crystallized intelligence and self-confidence, is used. The study indicated that modifications using base success probabilities over p = .70 lead to reduced measurement accuracy and - more seriously - a bias in the person parameter estimates for higher ability respondents. However, this was not the case for the motivator item algorithm, occasionally administering easier items as well. The second study (n = 191 thus compared the unmodified maximum-information algorithm with two motivator item algorithms, which differed with regard to the percentage of motivator items presented. The results indicate that respondents yield higher self-confidence estimates under the motivator item conditions. Furthermore, the three conditions did not differ from each other with regard to the total test duration. It can be concluded that a small number of easier motivator items is sufficient to preserve test-taking motivation throughout the test without a loss of test economy.

  6. Confidence and Cognitive Test Performance. Research Report. ETS RR-07-03

    Science.gov (United States)

    Stankov, Lazar; Lee, Jihyun

    2007-01-01

    This paper examines the nature of confidence in relation to cognitive abilities, personality traits, and metacognition. Confidence was measured as it was expressed in answers to each test item during the administration of reading and listening sections of the TOEFL® iBT. The confidence scores were correlated with the accuracy scores from the TOEFL…

  7. Confidence interval estimation for an empirical model quantifying the effect of soil moisture and plant development on soybean (Glycine max (L.) Merr.) leaf conductance

    Science.gov (United States)

    In this work, we address uncertainty analysis for a model, presented in a companion paper, quantifying the effect of soil moisture and plant development on soybean (Glycine max (L.) Merr.) leaf conductance. To achieve this we present several methods for confidence interval estimation. Estimation ...

  8. Methods for calculating confidence and credible intervals for the residual between-study variance in random effects meta-regression models

    Science.gov (United States)

    2014-01-01

    Background Meta-regression is becoming increasingly used to model study level covariate effects. However this type of statistical analysis presents many difficulties and challenges. Here two methods for calculating confidence intervals for the magnitude of the residual between-study variance in random effects meta-regression models are developed. A further suggestion for calculating credible intervals using informative prior distributions for the residual between-study variance is presented. Methods Two recently proposed and, under the assumptions of the random effects model, exact methods for constructing confidence intervals for the between-study variance in random effects meta-analyses are extended to the meta-regression setting. The use of Generalised Cochran heterogeneity statistics is extended to the meta-regression setting and a Newton-Raphson procedure is developed to implement the Q profile method for meta-analysis and meta-regression. WinBUGS is used to implement informative priors for the residual between-study variance in the context of Bayesian meta-regressions. Results Results are obtained for two contrasting examples, where the first example involves a binary covariate and the second involves a continuous covariate. Intervals for the residual between-study variance are wide for both examples. Conclusions Statistical methods, and R computer software, are available to compute exact confidence intervals for the residual between-study variance under the random effects model for meta-regression. These frequentist methods are almost as easily implemented as their established counterparts for meta-analysis. Bayesian meta-regressions are also easily performed by analysts who are comfortable using WinBUGS. Estimates of the residual between-study variance in random effects meta-regressions should be routinely reported and accompanied by some measure of their uncertainty. Confidence and/or credible intervals are well-suited to this purpose. PMID:25196829

  9. Reliability of 95% confidence interval revealed by expected quality-of-life scores: an example of nasopharyngeal carcinoma patients after radiotherapy using EORTC QLQ-C 30

    OpenAIRE

    Leung Henry WC; Wang Wen-Chung; Lin Shun-Jin; Chien Tsair-Wei; Lai Wen-Pin; Chan Agnes LF

    2010-01-01

    Abstract Background Many researchers use observed questionnaire scores to evaluate score reliability and to make conclusions and inferences regarding quality-of-life outcomes. The amount of false alarms from medical diagnoses that would be avoided if observed scores were substituted with expected scores is interesting, and understanding these differences is important for the care of cancer patients. Using expected scores to estimate the reliability of 95% confidence intervals (CIs) is rarely ...

  10. Improved Confidence Interval Estimation for Oscillometric Blood Pressure Measurement by Combining Bootstrap-After-Jackknife Function with Non-Gaussian Models

    OpenAIRE

    Soojeong Lee

    2014-01-01

    Confidence intervals (CIs) are generally not provided along with estimated systolic blood pressure (SBP) and diastolic blood pressure (DBP) measured using oscillometric blood pressure devices. No criteria exist to determine the CI from a small sample set of oscillometric blood pressure measurements. We provide an extended methodology to improve estimation of CIs of SBP and DBP based on a nonparametric bootstrap-after-jackknife function and a Bayesian approach. We use the nonparametric bootstr...

  11. [Reference Intervals of Standard Test Items in Ningen Dock Examination].

    Science.gov (United States)

    Yamakado, Minoru

    2016-03-01

    Reference intervals (RIs) were derived from records of 1,499,288 individuals who underwent ningen dock examination in 188 institutes which belong to Japan Society of Ningen Dock in 2012. Targets were 27 basic laboratory tests, including the body mass index (BMI) and systolic and diastolic blood pressures (SBP, DBP). Individuals fulfilling strict criteria were chosen: SBP dock results will enable the appropriate interpretation of test results in health screening, and promote the effective application of CDLs for therapeutic intervention, taking into account the sex, age, and other health attributes.

  12. Curve Fitting, Confidence Intervals and Envelopes, Correlations, and Monte Carlo Visualizations for Multilinear Problems in Chemistry: A General Spreadsheet Approach

    Science.gov (United States)

    Ogren, Paul; Davis, Brian; Guy, Nick

    2001-06-01

    A spreadsheet approach is used to fit multilinear functions with three adjustable parameters: ƒ = a1X1(x) + a2X2(x) + a3X3(x). Results are illustrated for three familiar examples: IR analysis of gaseous DCl, the electronic/vibrational spectrum of gaseous I2, and van Deemter plots of chromatographic data. These cases are simple enough for students in upper-level physical or advanced analytical courses to write and modify their own spreadsheets. In addition to the original x, y, and sy values, 12 columns are required: three for Xn(xi) values, six for Xn(xi)Xk(xi) product sums for the curvature matrix [a], and three for yi Xn(xi) sums for (b) in the vector equation (b) = [a](a). The Excel spreadsheet MINVERSE function provides the [e] error matrix from [a]. The [e] elements are then used to determine best-fit parameter values contained in (a). These spreadsheets also use a "dimensionless" or "reduced parameter" approach in calculating parameter weights, uncertainties, and correlations. Students can later enter data sets and fit parameters into a larger spreadsheet that uses Monte Carlo techniques to produce two-dimensional scatter plots. These correspond to Dc2 ellipsoidal cross-sections or projections and provide visual depictions of parameter uncertainties and correlations. The Monte Carlo results can also be used to estimate confidence envelopes for fitting plots.

  13. Guide for Calculating and Interpreting Effect Sizes and Confidence Intervals in Intellectual and Developmental Disability Research Studies

    Science.gov (United States)

    Dunst, Carl J.; Hamby, Deborah W.

    2012-01-01

    This paper includes a nontechnical description of methods for calculating effect sizes in intellectual and developmental disability studies. Different hypothetical studies are used to illustrate how null hypothesis significance testing (NHST) and effect size findings can result in quite different outcomes and therefore conflicting results. Whereas…

  14. Test of a trust and confidence model in the applied context of electromagnetic field (EMF) risks.

    Science.gov (United States)

    Siegrist, Michael; Earle, Timothy C; Gutscher, Heinz

    2003-08-01

    Trust is an important factor in risk management. There is little agreement among researchers, however, on how trust in risk management should be studied. Based on a comprehensive review of the trust literature a "dual-mode model of social trust and confidence" is proposed. Trust and confidence are separate but, under some circumstances, interacting sources of cooperation. Trust is based on value similarity, and confidence is based on performance. According to our model, judging similarity between an observer's currently active values and the values attributed to others determines social trust. Thus, the basis for trust is a judgment that the person to be trusted would act as the trusting person would. Interpretation of the other's performance influences confidence. Both social trust and confidence have an impact on people's willingness to cooperate (e.g., accept electromagnetic fields or EMF in the neighborhood). The postulated model was tested in the applied context of EMF risks. Structural equation modeling procedures and data from a random sample of 1,313 Swiss citizens between 18 and 74 years old were used. Results indicated that after minor modifications the model explained the data very well. In the applied context of EMF risks, both trust and confidence had an impact on cooperation. Results suggest that the dual-mode model of social trust and confidence could be used as a common framework in the field of trust and risk management. Practical implications of the results are discussed.

  15. The errors of our ways: taking account of error in computer-aided drug design to build confidence intervals for our next 25 years.

    Science.gov (United States)

    Stouch, Terry Richard

    2012-01-01

    The future of the advancement as well as the reputation of computer-aided drug design will be guided by a more thorough understanding of the domain of applicability of our methods and the errors and confidence intervals of their results. The implications of error in current force fields applied to drug design are given are given as an example. Even as our science advances and our hardware become increasingly more capable, our software will be perhaps the most important aspect in this realization. Some recommendations for the future are provided. Education of users is essential for proper use and interpretation of computational results in the future.

  16. Flight Test Evaluation of the ATD-1 Interval Management Application

    Science.gov (United States)

    Swieringa, Kurt A.; Wilson, Sara R.; Baxley, Brian T.; Roper, Roy D.; Abbott, Terence S.; Levitt, Ian; Scharl, Julien

    2017-01-01

    Interval Management (IM) is a concept designed to be used by air traffic controllers and flight crews to more efficiently and precisely manage inter-aircraft spacing. Both government and industry have been working together to develop the IM concept and standards for both ground automation and supporting avionics. NASA contracted with Boeing, Honeywell, and United Airlines to build and flight test an avionics prototype based on NASA's spacing algorithm and conduct a flight test. The flight test investigated four different types of IM operations over the course of nineteen days, and included en route, arrival, and final approach phases of flight. This paper examines the spacing accuracy achieved during the flight test and the rate of speed commands provided to the flight crew. Many of the time-based IM operations met or exceeded the operational design goals set out in the standards for the maintain operations and a subset of the achieve operations. Those operations which did not meet the goals were due to issues that are identified and will be further analyzed.

  17. Biological variation: Evaluation of methods for constructing confidence intervals for estimates of within-person biological variation for different distributions of the within-person effect.

    Science.gov (United States)

    Røraas, Thomas; Støve, Bård; Petersen, Per Hyltoft; Sandberg, Sverre

    2017-05-01

    Precise estimates of the within-person biological variation, CVI, can be essential both for monitoring patients and for setting analytical performance specifications. The confidence interval, CI, may be used to evaluate the reliability of an estimate, as it is a good measure of the uncertainty of the estimated CVI. The aim of the present study is to evaluate and establish methods for constructing a CI with the correct coverage probability and non-cover probability when estimating CVI. Data based on 3 models for distributions for the within-person effect were simulated to assess the performance of 3 methods for constructing confidence intervals; the formula based method for the nested ANOVA, the percentile bootstrap and the bootstrap-t methods. The performance of the evaluated methods for constructing a CI varied, both dependent on the size of the CVI and the type of distributions. The bootstrap-t CI have good and stable performance for the models evaluated, while the formula based are more distribution dependent. The percentile bootstrap performs poorly. CI is an essential part of estimation of the within-person biological variation. Good coverage probability and non-cover probabilities for CI are achievable by using the bootstrap-t combined with CV-ANOVA. Supplemental R-code is provided online. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Standard errors and confidence intervals in within-subjects designs: generalizing Loftus and Masson (1994) and avoiding the biases of alternative accounts.

    Science.gov (United States)

    Franz, Volker H; Loftus, Geoffrey R

    2012-06-01

    Repeated measures designs are common in experimental psychology. Because of the correlational structure in these designs, the calculation and interpretation of confidence intervals is nontrivial. One solution was provided by Loftus and Masson (Psychonomic Bulletin & Review 1:476-490, 1994). This solution, although widely adopted, has the limitation of implying same-size confidence intervals for all factor levels, and therefore does not allow for the assessment of variance homogeneity assumptions (i.e., the circularity assumption, which is crucial for the repeated measures ANOVA). This limitation and the method's perceived complexity have sometimes led scientists to use a simplified variant, based on a per-subject normalization of the data (Bakeman & McArthur, Behavior Research Methods, Instruments, & Computers 28:584-589, 1996; Cousineau, Tutorials in Quantitative Methods for Psychology 1:42-45, 2005; Morey, Tutorials in Quantitative Methods for Psychology 4:61-64, 2008; Morrison & Weaver, Behavior Research Methods, Instruments, & Computers 27:52-56, 1995). We show that this normalization method leads to biased results and is uninformative with regard to circularity. Instead, we provide a simple, intuitive generalization of the Loftus and Masson method that allows for assessment of the circularity assumption.

  19. Estimating negative likelihood ratio confidence when test sensitivity is 100%: A bootstrapping approach.

    Science.gov (United States)

    Marill, Keith A; Chang, Yuchiao; Wong, Kim F; Friedman, Ari B

    2017-08-01

    Objectives Assessing high-sensitivity tests for mortal illness is crucial in emergency and critical care medicine. Estimating the 95% confidence interval (CI) of the likelihood ratio (LR) can be challenging when sample sensitivity is 100%. We aimed to develop, compare, and automate a bootstrapping method to estimate the negative LR CI when sample sensitivity is 100%. Methods The lowest population sensitivity that is most likely to yield sample sensitivity 100% is located using the binomial distribution. Random binomial samples generated using this population sensitivity are then used in the LR bootstrap. A free R program, "bootLR," automates the process. Extensive simulations were performed to determine how often the LR bootstrap and comparator method 95% CIs cover the true population negative LR value. Finally, the 95% CI was compared for theoretical sample sizes and sensitivities approaching and including 100% using: (1) a technique of individual extremes, (2) SAS software based on the technique of Gart and Nam, (3) the Score CI (as implemented in the StatXact, SAS, and R PropCI package), and (4) the bootstrapping technique. Results The bootstrapping approach demonstrates appropriate coverage of the nominal 95% CI over a spectrum of populations and sample sizes. Considering a study of sample size 200 with 100 patients with disease, and specificity 60%, the lowest population sensitivity with median sample sensitivity 100% is 99.31%. When all 100 patients with disease test positive, the negative LR 95% CIs are: individual extremes technique (0,0.073), StatXact (0,0.064), SAS Score method (0,0.057), R PropCI (0,0.062), and bootstrap (0,0.048). Similar trends were observed for other sample sizes. Conclusions When study samples demonstrate 100% sensitivity, available methods may yield inappropriately wide negative LR CIs. An alternative bootstrapping approach and accompanying free open-source R package were developed to yield realistic estimates easily. This

  20. Reliability of 95% confidence interval revealed by expected quality-of-life scores: an example of nasopharyngeal carcinoma patients after radiotherapy using EORTC QLQ-C 30.

    Science.gov (United States)

    Chien, Tsair-Wei; Lin, Shun-Jin; Wang, Wen-Chung; Leung, Henry W C; Lai, Wen-Pin; Chan, Agnes L F

    2010-07-13

    Many researchers use observed questionnaire scores to evaluate score reliability and to make conclusions and inferences regarding quality-of-life outcomes. The amount of false alarms from medical diagnoses that would be avoided if observed scores were substituted with expected scores is interesting, and understanding these differences is important for the care of cancer patients. Using expected scores to estimate the reliability of 95% confidence intervals (CIs) is rarely reported in published papers. We investigated the reliability of patient responses to a quality-of-life questionnaire and made recommendations for future studies of the quality of life of patients. A total of 115 patients completed the EORTC core questionnaire QLQ-C30 (version 3) after radiotherapy. The observed response scores, assumed to be one-dimensional, were summed and transformed into expected scores using the Rasch rating scale model with WINSTEPS software. A series of simulations was performed using a unified bootstrap procedure after manipulating scenarios with different questionnaire lengths and patient numbers to estimate the reliability at 95% confidence intervals. Skewness analyses of the 95% CIs were compared to detect different effects between groups according to the two data sets of observed and expected response scores. We found that (1) it is necessary to report CIs for reliability and skewness coefficients in papers; (2) data derived from expected response scores are preferable to making inferences; and (3) visual representations displaying the 95% CIs of skewness values applied to item-by-item analyses can provide a useful interpretation of quality-of-life outcomes. Reliability coefficients can be reported with 95% CIs by statistical software to evaluate the internal consistency of respondent scores on questionnaire items. The SPSS syntax procedures for estimating the reliability of the 95% CI, expected score generation and visual skewness analyses are demonstrated in this

  1. The interval shuttle run test for intermittent sport players: evaluation of reliability.

    Science.gov (United States)

    Lemmink, Koen A P M; Visscher, Chris; Lambert, Michael I; Lamberts, Robert P

    2004-11-01

    The reliability of the interval shuttle run test (ISRT) as a submaximal and maximal field test to measure intermittent endurance capacity was examined. During the ISRT, participants alternately run for 30 seconds and walk for 15 seconds. The running speed is increased from 10 km.h(-1) every 90 seconds until exhaustion. Within a 2-week period, 17 intermittent sport players (i.e., 10 men and 7 women) performed the ISRT twice in a sports hall under well-standardized conditions. Heart rates per speed and total number of runs were assessed as submaximal and maximal performance measures. With the exception of the heart rates at 10.0 km.h(-1) for men and 10.0, 12.0, and 13.5 km.h(-1) for women, zero lay within the 95% confidence interval of the mean differences, indicating that no bias existed between the outcome measures at the 2 test sessions (absolute reliability). The results illustrate that it is important to control for heart rate before the start of the ISRT. Relative reliability was high (intraclass correlation coefficient > or = 0.86). We conclude that the reliability of the ISRT as a submaximal and maximal field test for intermittent sport players is supported by the results.

  2. Reliability of 95% confidence interval revealed by expected quality-of-life scores: an example of nasopharyngeal carcinoma patients after radiotherapy using EORTC QLQ-C 30

    Directory of Open Access Journals (Sweden)

    Leung Henry WC

    2010-07-01

    Full Text Available Abstract Background Many researchers use observed questionnaire scores to evaluate score reliability and to make conclusions and inferences regarding quality-of-life outcomes. The amount of false alarms from medical diagnoses that would be avoided if observed scores were substituted with expected scores is interesting, and understanding these differences is important for the care of cancer patients. Using expected scores to estimate the reliability of 95% confidence intervals (CIs is rarely reported in published papers. We investigated the reliability of patient responses to a quality-of-life questionnaire and made recommendations for future studies of the quality of life of patients. Methods A total of 115 patients completed the EORTC core questionnaire QLQ-C30 (version 3 after radiotherapy. The observed response scores, assumed to be one-dimensional, were summed and transformed into expected scores using the Rasch rating scale model with WINSTEPS software. A series of simulations was performed using a unified bootstrap procedure after manipulating scenarios with different questionnaire lengths and patient numbers to estimate the reliability at 95% confidence intervals. Skewness analyses of the 95% CIs were compared to detect different effects between groups according to the two data sets of observed and expected response scores. Results We found that (1 it is necessary to report CIs for reliability and skewness coefficients in papers; (2 data derived from expected response scores are preferable to making inferences; and (3 visual representations displaying the 95% CIs of skewness values applied to item-by-item analyses can provide a useful interpretation of quality-of-life outcomes. Conclusion Reliability coefficients can be reported with 95% CIs by statistical software to evaluate the internal consistency of respondent scores on questionnaire items. The SPSS syntax procedures for estimating the reliability of the 95% CI, expected score

  3. Evaluating the Equal-Interval Hypothesis with Test Score Scales

    Science.gov (United States)

    Domingue, Benjamin Webre

    2012-01-01

    In psychometrics, it is difficult to verify that measurement instruments can be used to produce numeric values with the desirable property that differences between units are equal-interval because the attributes being measured are latent. The theory of additive conjoint measurement (e.g., Krantz, Luce, Suppes, & Tversky, 1971, ACM) guarantees…

  4. Improved Confidence Interval Estimation for Oscillometric Blood Pressure Measurement by Combining Bootstrap-After-Jackknife Function with Non-Gaussian Models

    Directory of Open Access Journals (Sweden)

    Soojeong Lee

    2014-01-01

    Full Text Available Confidence intervals (CIs are generally not provided along with estimated systolic blood pressure (SBP and diastolic blood pressure (DBP measured using oscillometric blood pressure devices. No criteria exist to determine the CI from a small sample set of oscillometric blood pressure measurements. We provide an extended methodology to improve estimation of CIs of SBP and DBP based on a nonparametric bootstrap-after-jackknife function and a Bayesian approach. We use the nonparametric bootstrap-after-jackknife function to reduce maximum amplitude outliers. Improved pseudomaximum amplitudes (PMAs and pseudoenvelopes (PEs are derived from the pseudomeasurements. Moreover, the proposed algorithm uses an unfixed ratio obtained by employing non-Gaussian models based on the Bayesian technique to estimate the SBP and DBP ratios for individual subjects. The CIs obtained through our proposed approach are narrower than those obtained using the traditional Student t-distribution method. The mean difference (MD and standard deviation (SD of the SBP and DBP estimates using our proposed approach are better than the estimates obtained by conventional fixed ratios based on the PMA and PE (PMAE.

  5. Qualification Testing Versus Quantitative Reliability Testing of PV - Gaining Confidence in a Rapidly Changing Technology: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, Sarah [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Repins, Ingrid L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hacke, Peter L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jordan, Dirk [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kempe, Michael D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Whitfield, Kent [Underwriters Laboratories; Phillips, Nancy [DuPont; Sample, Tony [European Commission; Monokroussos, Christos [TUV Rheinland; Hsi, Edward [Swiss RE; Wohlgemuth, John [PowerMark Corporation; Seidel, Peter [First Solar; Jahn, Ulrike [TUV Rheinland; Tanahashi, Tadanori [National Institute of Advanced Industrial Science and Technology; Chen, Yingnan [China General Certification Center; Jaeckel, Bengt [Underwriters Laboratories; Yamamichi, Masaaki [RTS Corporation

    2017-10-05

    Continued growth of PV system deployment would be enhanced by quantitative, low-uncertainty predictions of the degradation and failure rates of PV modules and systems. The intended product lifetime (decades) far exceeds the product development cycle (months), limiting our ability to reduce the uncertainty of the predictions for this rapidly changing technology. Yet, business decisions (setting insurance rates, analyzing return on investment, etc.) require quantitative risk assessment. Moving toward more quantitative assessments requires consideration of many factors, including the intended application, consequence of a possible failure, variability in the manufacturing, installation, and operation, as well as uncertainty in the measured acceleration factors, which provide the basis for predictions based on accelerated tests. As the industry matures, it is useful to periodically assess the overall strategy for standards development and prioritization of research to provide a technical basis both for the standards and the analysis related to the application of those. To this end, this paper suggests a tiered approach to creating risk assessments. Recent and planned potential improvements in international standards are also summarized.

  6. Flight Deck Interval Management Flight Test Final Report

    Science.gov (United States)

    Tulder, Paul V.

    2017-01-01

    This document provides a summary of the avionics design, implementation, and evaluation activities conducted for the ATD-1 Avionics Phase 2. The flight test data collection and a subset of the analysis results are described. This report also documents lessons learned, conclusions, and recommendations to guide further development efforts.

  7. Association between the 6-minute walk test and exercise confidence in patients with heart failure: A prospective observational study.

    Science.gov (United States)

    Ha, Francis J; Toukhsati, Samia R; Cameron, James D; Yates, Rosie; Hare, David L

    2017-10-21

    Exercise confidence predicts exercise adherence in heart failure (HF) patients. The association between simple tests of functional capacity on exercise confidence are not known. To evaluate the association between a single 6-min walk test (6MWT) and exercise confidence in HF patients. Observational study enrolling HF outpatients who completed the Cardiac Depression Scale and an Exercise Confidence Survey at baseline and following the 6MWT. Paired t-test was used to compare repeated-measures data, while Repeated Measures Analysis of Covariance was used for multivariate analysis. 106 HF patients were enrolled in the study (males, 82%; mean age, 64 ± 12 years). Baseline Exercise Confidence was inversely associated with age (p Confidence (F(1,92) = 5.0, p = 0.03) after adjustment for age, gender, HF duration, NYHA class and depression. The 6MWT is associated with improved exercise confidence in HF patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. The relationship between the interval shuttle run test and maximal oxygen uptake in soccer players

    NARCIS (Netherlands)

    Lemmink, KAPM; Visscher, C

    2003-01-01

    The aim of this study was to determine the relationship between the interval shuttle run test (ISRT) and maximal oxygen uptake (VO2max) in soccer players. The ISRT was developed to measure interval endurance capacity. During the ISRT, subjects alternately run for 30 sec and walk for 15 sec with

  9. Solar Alpha Rotary Joint (SARJ) Lubrication Interval Test and Evaluation (LITE). Post-Test Grease Analysis

    Science.gov (United States)

    Golden, Johnny L.; Martinez, James E.; Devivar, Rodrigo V.

    2015-01-01

    The Solar Alpha Rotary Joint (SARJ) is a mechanism of the International Space Station (ISS) that orients the solar power generating arrays toward the sun as the ISS orbits our planet. The orientation with the sun must be maintained to fully charge the ISS batteries and maintain all the other ISS electrical systems operating properly. In 2007, just a few months after full deployment, the starboard SARJ developed anomalies that warranted a full investigation including ISS Extravehicular Activity (EVA). The EVA uncovered unexpected debris that was due to degradation of a nitride layer on the SARJ bearing race. ISS personnel identified the failure root-cause and applied an aerospace grease to lubricate the area associated with the anomaly. The corrective action allowed the starboard SARJ to continue operating within the specified engineering parameters. The SARJ LITE (Lubrication Interval Test and Evaluation) program was initiated by NASA, Lockheed Martin, and Boeing to simulate the operation of the ISS SARJ for an extended time. The hardware was designed to test and evaluate the exact material components used aboard the ISS SARJ, but in a controlled area where engineers could continuously monitor the performance. After running the SARJ LITE test for an equivalent of 36+ years of continuous use, the test was opened to evaluate the metallography and lubrication. We have sampled the SARJ LITE rollers and plate to fully assess the grease used for lubrication. Chemical and thermal analysis of these samples has generated information that has allowed us to assess the location, migration, and current condition of the grease. The collective information will be key toward understanding and circumventing any performance deviations involving the ISS SARJ in the years to come.

  10. User guide to the UNC1NLI1 package and three utility programs for computation of nonlinear confidence and prediction intervals using MODFLOW-2000

    DEFF Research Database (Denmark)

    Christensen, Steen; Cooley, R.L.

    and prediction intervals for most types of functions that can be computed by a MODFLOW-2000 model calibrated by the Parameter-Estimation Process. The types of functions for which the Process works include hydraulic heads, hydraulic head differences, head-dependent flows computed by the head- dependent flow...... packages for drains (DRN6), rivers (RIV6), general-head boundaries (GHB6), streams (STR6), drain-return cells (DRT1), and constant-head boundaries (CHD), and for differences between flows computed by any of the mentioned flow packages. The UNC Process does not allow computation of intervals......This report introduces and documents the Uncertainty (UNC) Process, a new Process in MODFLOW-2000 that calculates uncertainty measures for model parameters and for predictions produced by the model. Uncertainty measures can be computed by various methods, but when regression is applied to calibrate...

  11. Confidence Intervals and "F" Tests for Intraclass Correlation Coefficients Based on Three-Way Mixed Effects Models

    Science.gov (United States)

    Zhou, Hong; Muellerleile, Paige; Ingram, Debra; Wong, Seok P.

    2011-01-01

    Intraclass correlation coefficients (ICCs) are commonly used in behavioral measurement and psychometrics when a researcher is interested in the relationship among variables of a common class. The formulas for deriving ICCs, or generalizability coefficients, vary depending on which models are specified. This article gives the equations for…

  12. Predictors of Willingness to Read in English: Testing a Model Based on Possible Selves and Self-Confidence

    Science.gov (United States)

    Khajavy, Gholam Hassan; Ghonsooly, Behzad

    2017-01-01

    The aim of the present study is twofold. First, it tests a model of willingness to read (WTR) based on L2 motivation and communication confidence (communication anxiety and perceived communicative competence). Second, it applies the recent theory of L2 motivation proposed by Dörnyei [2005. "The Psychology of Language Learner: Individual…

  13. Contribution of age and balance confidence to functional mobility test performance: diagnostic accuracy of L test and normal-paced timed up and go.

    Science.gov (United States)

    Medley, Ann; Thompson, Mary

    2015-01-01

    Falls are a public health priority. Contribution of age and balance confidence to functional mobility is unknown. Appropriate cutoff scores for normal-paced Timed Up and Go (TUG) and L test may improve ability to determine fall risk. Purposes were to determine the contribution of age and balance confidence to functional mobility, determine the association between balance confidence and fall risk, and propose cutoffs. A prospective, descriptive study was conducted in the community with 105 apparently healthy adults at the age of 60 to 96 years. Participants provided fall history. Examiners administered the Activities-Specific Balance Confidence Scale, Dynamic Gait Index (DGI), Functional Gait Assessment, TUG, and L test. Linear regression determined the balance confidence contribution. Multivariate analysis of covariance determined differences between participants with high and low confidence. Sensitivity, specificity, overall diagnostic accuracy, and receiver operating characteristics curves were used to estimate cutoffs. Performance across functional mobility tests declined with age. A total of 46 participants had low balance confidence. Depending on the outcome measure, 16% to 30% of participants' balance confidence and physical performance did not match. Regression analysis revealed that the best model combines age and balance confidence. Regardless of age, participants with high and low balance confidence differed on the basis of multivariate analysis of covariance. Receiver operating characteristics curves supported the diagnostic accuracy of 12 or more seconds (normal-paced TUG) and 25.5 or more seconds (L test) cutoffs. We confirmed that functional mobility, as measured by the L test, declines with age similar to other outcome measures. Balance confidence contributes to functional mobility performance, and the 2 constructs do not match about 25% of the time. Because these constructs may not match, the need to formally assess balance confidence is warranted

  14. Exploration of analysis methods for diagnostic imaging tests: problems with ROC AUC and confidence scores in CT colonography.

    Science.gov (United States)

    Mallett, Susan; Halligan, Steve; Collins, Gary S; Altman, Doug G

    2014-01-01

    Different methods of evaluating diagnostic performance when comparing diagnostic tests may lead to different results. We compared two such approaches, sensitivity and specificity with area under the Receiver Operating Characteristic Curve (ROC AUC) for the evaluation of CT colonography for the detection of polyps, either with or without computer assisted detection. In a multireader multicase study of 10 readers and 107 cases we compared sensitivity and specificity, using radiological reporting of the presence or absence of polyps, to ROC AUC calculated from confidence scores concerning the presence of polyps. Both methods were assessed against a reference standard. Here we focus on five readers, selected to illustrate issues in design and analysis. We compared diagnostic measures within readers, showing that differences in results are due to statistical methods. Reader performance varied widely depending on whether sensitivity and specificity or ROC AUC was used. There were problems using confidence scores; in assigning scores to all cases; in use of zero scores when no polyps were identified; the bimodal non-normal distribution of scores; fitting ROC curves due to extrapolation beyond the study data; and the undue influence of a few false positive results. Variation due to use of different ROC methods exceeded differences between test results for ROC AUC. The confidence scores recorded in our study violated many assumptions of ROC AUC methods, rendering these methods inappropriate. The problems we identified will apply to other detection studies using confidence scores. We found sensitivity and specificity were a more reliable and clinically appropriate method to compare diagnostic tests.

  15. The interval shuttle run test for intermittent sport players : evaluation of reliability

    NARCIS (Netherlands)

    Lemmink, K.A.P.M.; Visscher, C.; Lambert, M.I.; Lamberts, R.P.

    2004-01-01

    The reliability of the interval shuttle run test (ISRT) as a submaximal and maximal field test to measure intermittent endurance capacity was examined. During the ISRT, participants alternately run for 30 seconds and walk for 15 seconds. The running speed is increased from 10 km.h(-1) every 90

  16. Visual Confidence.

    Science.gov (United States)

    Mamassian, Pascal

    2016-10-14

    Visual confidence refers to an observer's ability to judge the accuracy of her perceptual decisions. Even though confidence judgments have been recorded since the early days of psychophysics, only recently have they been recognized as essential for a deeper understanding of visual perception. The reluctance to study visual confidence may have come in part from obtaining convincing experimental evidence in favor of metacognitive abilities rather than just perceptual sensitivity. Some effort has thus been dedicated to offer different experimental paradigms to study visual confidence in humans and nonhuman animals. To understand the origins of confidence judgments, investigators have developed two competing frameworks. The approach based on signal decision theory is popular but fails to account for response times. In contrast, the approach based on accumulation of evidence models naturally includes the dynamics of perceptual decisions. These models can explain a range of results, including the apparently paradoxical dissociation between performance and confidence that is sometimes observed.

  17. The patients' perspective of international normalized ratio self-testing, remote communication of test results and confidence to move to self-management.

    Science.gov (United States)

    Grogan, Anne; Coughlan, Michael; Prizeman, Geraldine; O'Connell, Niamh; O'Mahony, Nora; Quinn, Katherine; McKee, Gabrielle

    2017-12-01

    To elicit the perceptions of patients, who self-tested their international normalized ratio and communicated their results via a text or phone messaging system, to determine their satisfaction with the education and support that they received and to establish their confidence to move to self-management. Self-testing of international normalized ratio has been shown to be reliable and is fast becoming common practice. As innovations are introduced to point of care testing, more research is needed to elicit patients' perceptions of the self-testing process. This three site study used a cross-sectional prospective descriptive survey. Three hundred and thirty patients who were prescribed warfarin and using international normalized ratio self-testing were invited to take part in the study. The anonymous survey examined patient profile, patients' usage, issues, perceptions, confidence and satisfaction with using the self-testing system and their preparedness for self-management of warfarin dosage. The response rate was 57% (n = 178). Patients' confidence in self-testing was high (90%). Patients expressed a high level of satisfaction with the support received, but expressed the need for more information on support groups, side effects of warfarin, dietary information and how to dispose of needles. When asked if they felt confident to adjust their own warfarin levels 73% agreed. Chi-squared tests for independence revealed that none of the patient profile factors examined influenced this confidence. The patients cited the greatest advantages of the service were reduced burden, more autonomy, convenience and ease of use. The main disadvantages cited were cost and communication issues. Patients were satisfied with self-testing. The majority felt they were ready to move to self-management. The introduction of innovations to remote point of care testing, such as warfarin self-testing, needs to have support at least equal to that provided in a hospital setting. © 2017 John

  18. Exploration of analysis methods for diagnostic imaging tests: problems with ROC AUC and confidence scores in CT colonography.

    Directory of Open Access Journals (Sweden)

    Susan Mallett

    Full Text Available BACKGROUND: Different methods of evaluating diagnostic performance when comparing diagnostic tests may lead to different results. We compared two such approaches, sensitivity and specificity with area under the Receiver Operating Characteristic Curve (ROC AUC for the evaluation of CT colonography for the detection of polyps, either with or without computer assisted detection. METHODS: In a multireader multicase study of 10 readers and 107 cases we compared sensitivity and specificity, using radiological reporting of the presence or absence of polyps, to ROC AUC calculated from confidence scores concerning the presence of polyps. Both methods were assessed against a reference standard. Here we focus on five readers, selected to illustrate issues in design and analysis. We compared diagnostic measures within readers, showing that differences in results are due to statistical methods. RESULTS: Reader performance varied widely depending on whether sensitivity and specificity or ROC AUC was used. There were problems using confidence scores; in assigning scores to all cases; in use of zero scores when no polyps were identified; the bimodal non-normal distribution of scores; fitting ROC curves due to extrapolation beyond the study data; and the undue influence of a few false positive results. Variation due to use of different ROC methods exceeded differences between test results for ROC AUC. CONCLUSIONS: The confidence scores recorded in our study violated many assumptions of ROC AUC methods, rendering these methods inappropriate. The problems we identified will apply to other detection studies using confidence scores. We found sensitivity and specificity were a more reliable and clinically appropriate method to compare diagnostic tests.

  19. Estimation of local confidence limit for 6 MV photon beam IMRT system using AAPM TG 119 test protocol

    Directory of Open Access Journals (Sweden)

    Avinash Kadam

    2016-03-01

    Full Text Available Purpose: The aim of this study was to estimate local confidence limit for 6 MV photon beam based intensity modulated radiation therapy (IMRT using TG119 test protocol.Methods: The American Association of Physicists in Medicine (AAPM Task Group 119 (TG119 prescribed a protocol to evaluate overall accuracy of IMRT system rather than independent uncertainty in dose calculation, dose delivery and measurement system. Two preliminary and five clinical test cases were created based on dose prescriptions and planning objectives given by TG119 report. Verification plans were created in a planning slab phantom, 2D Matrix dosimetry system (I’MatriXX with multicube phantom and aS-1000 electronic portal imaging device (EPID. Radiation absorbed doses to high dose points in the planning target volume (PTV region and low dose points in avoidance structures were measured using CC13 ionization chamber having sensitive volume of 0.13 cm3. The measured and planned doses were normalized with respect to their prescription doses and intercompared. The gamma analysis was carried out for both I’MatriXX and EPID, adopting the acceptance criteria of 3% DD (dose difference and 3 mm DTA (distance to agreement with 10% threshold dose.Results: For the point dose measurements with ion chamber, the average dose difference ratio in high dose low gradient PTV region was -0.0133 ± 0.012 corresponding to a confidence limit of 0.037. The average dose difference in low dose region (avoidance structure was -0.00004 ± 0.010 corresponding to a confidence limit of 0.021. The average percentage of points passing the gamma criteria of 3% DD and 3 mm DTA for composite planar dose distribution measured by I’MatriXX was 99.47 ± 0.43 which corresponds to a confidence limit of 1.38 (i.e. 98.62% passing. Similarly, the average percentage of points passing the gamma criteria of 3% DD and 3 mm DTA for per-field dose distribution measured by EPID was 98.00 ± 2.49 which corresponds to a

  20. Hypothesis Testing of Inclusion of the Tolerance Interval for the Assessment of Food Safety.

    Directory of Open Access Journals (Sweden)

    Hungyen Chen

    Full Text Available In the testing of food quality and safety, we contrast the contents of the newly proposed food (genetically modified food against those of conventional foods. Because the contents vary largely between crop varieties and production environments, we propose a two-sample test of substantial equivalence that examines the inclusion of the tolerance intervals of the two populations, the population of the contents of the proposed food, which we call the target population, and the population of the contents of the conventional food, which we call the reference population. Rejection of the test hypothesis guarantees that the contents of the proposed foods essentially do not include outliers in the population of the contents of the conventional food. The existing tolerance interval (TI0 is constructed to have at least a pre-specified level of the coverage probability. Here, we newly introduce the complementary tolerance interval (TI1 that is guaranteed to have at most a pre-specified level of the coverage probability. By applying TI0 and TI1 to the samples from the target population and the reference population respectively, we construct a test statistic for testing inclusion of the two tolerance intervals. To examine the performance of the testing procedure, we conducted a simulation that reflects the effects of gene and environment, and residual from a crop experiment. As a case study, we applied the hypothesis testing to test if the distribution of the protein content of rice in Kyushu area is included in the distribution of the protein content in the other areas in Japan.

  1. Sex differences in mathematical achievement: Grades, national test, and self-confidence

    Directory of Open Access Journals (Sweden)

    Egorova, Marina S.

    2016-09-01

    Full Text Available Academic achievement, which is inherently an indicator of progress in the curriculum, can also be viewed as an indirect measure of cognitive development, social adaptation, and motivational climate characteristics. In addition to its direct application, academic achievement is used as a mediating factor in the study of various phenomena, from the etiology of learning disabilities to social inequality. Analysis of sex differences in mathematical achievement is considered particularly important for exploring academic achievement, since creating an adequate educational environment with equal opportunities for boys and girls serves as a prerequisite for improving the overall mathematical and technical literacy that is crucial for modern society, creates balanced professional opportunities, and destroys traditional stereotypes about the roles of men and women in society. The objective of our research was to analyze sex differences in mathematical achievement among high school students and to compare various methods for diagnosing academic performance, such as school grades, test scores, and self-concept. The results were obtained through two population studies whose samples are representative of the Russian population in the relevant age group. Study 1 looked at sex differences in math grades among twins (n = 1,234 pairs and singletons (n = 2,227 attending high school. The sample of Study 2 comprised all twins who took the Unified State Examination in 2010–2012. The research analyzed sex differences in USE math scores across the entire sample and within the extreme subgroups. It also explored differences between boys and girls in opposite-sex dizygotic (DZ twin pairs. The key results were as follows. No difference in mathematical achievement was observed between twins and singletons. Sex differences were found in all measures of mathematical achievement. Girls had higher school grades in math than boys, while boys outperformed girls in USE math

  2. Consumers report lower confidence in their genetics knowledge following direct-to-consumer personal genomic testing.

    Science.gov (United States)

    Carere, Deanna Alexis; Kraft, Peter; Kaphingst, Kimberly A; Roberts, J Scott; Green, Robert C

    2016-01-01

    The aim of this study was to measure changes to genetics knowledge and self-efficacy following personal genomic testing (PGT). New customers of 23andMe and Pathway Genomics completed a series of online surveys. We measured genetics knowledge (nine true/false items) and genetics self-efficacy (five Likert-scale items) before receipt of results and 6 months after results and used paired methods to evaluate change over time. Correlates of change (e.g., decision regret) were identified using linear regression. 998 PGT customers (59.9% female; 85.8% White; mean age 46.9 ± 15.5 years) were included in our analyses. Mean genetics knowledge score was 8.15 ± 0.95 (out of 9) at baseline and 8.25 ± 0.92 at 6 months (P = 0.0024). Mean self-efficacy score was 29.06 ± 5.59 (out of 35) at baseline and 27.7 ± 5.46 at 6 months (P self-efficacy following PGT. Change in self-efficacy was positively associated with health-care provider consultation (P = 0.0042), impact of PGT on perceived control over one's health (P self-efficacy following PGT may reflect an appropriate reevaluation by consumers in response to receiving complex genetic information.Genet Med 18 1, 65-72.

  3. Generating confidence intervals on biological networks

    Directory of Open Access Journals (Sweden)

    Stumpf Michael PH

    2007-11-01

    Full Text Available Abstract Background In the analysis of networks we frequently require the statistical significance of some network statistic, such as measures of similarity for the properties of interacting nodes. The structure of the network may introduce dependencies among the nodes and it will in general be necessary to account for these dependencies in the statistical analysis. To this end we require some form of Null model of the network: generally rewired replicates of the network are generated which preserve only the degree (number of interactions of each node. We show that this can fail to capture important features of network structure, and may result in unrealistic significance levels, when potentially confounding additional information is available. Methods We present a new network resampling Null model which takes into account the degree sequence as well as available biological annotations. Using gene ontology information as an illustration we show how this information can be accounted for in the resampling approach, and the impact such information has on the assessment of statistical significance of correlations and motif-abundances in the Saccharomyces cerevisiae protein interaction network. An algorithm, GOcardShuffle, is introduced to allow for the efficient construction of an improved Null model for network data. Results We use the protein interaction network of S. cerevisiae; correlations between the evolutionary rates and expression levels of interacting proteins and their statistical significance were assessed for Null models which condition on different aspects of the available data. The novel GOcardShuffle approach results in a Null model for annotated network data which appears better to describe the properties of real biological networks. Conclusion An improved statistical approach for the statistical analysis of biological network data, which conditions on the available biological information, leads to qualitatively different results compared to approaches which ignore such annotations. In particular we demonstrate the effects of the biological organization of the network can be sufficient to explain the observed similarity of interacting proteins.

  4. Long-term maintenance of immediate or delayed extinction is determined by the extinction-test interval

    OpenAIRE

    Johnson, Justin S.; Escobar, Martha; Kimble, Whitney L.

    2010-01-01

    Short acquisition-extinction intervals (immediate extinction) can lead to either more or less spontaneous recovery than long acquisition-extinction intervals (delayed extinction). Using rat subjects, we observed less spontaneous recovery following immediate than delayed extinction (Experiment 1). However, this was the case only if a relatively long extinction-test interval was used; a relatively short extinction-test interval yielded the opposite result (Experiment 2). Previous data appear co...

  5. Exercise testing to enhance wives' confidence in their husbands' cardiac capability soon after clinically uncomplicated acute myocardial infarction.

    Science.gov (United States)

    Taylor, C B; Bandura, A; Ewart, C K; Miller, N H; DeBusk, R F

    1985-03-01

    The effects of wives' involvement in their husbands' performance of treadmill exercise testing 3 weeks after clinically uncomplicated acute myocardial infarction was compared in 10 wives who did not observe the test, 10 who observed the test, and 10 who observed and participated in the test themselves. In a counseling session after the treadmill test, couples were fully informed about the patient's capacity to perform various physical activities. Wives' final ratings of confidence (perceived efficacy) in their husbands' physical and cardiac capability were significantly (p less than 0.05) higher in those who also performed the test than in the other 2 groups. Only wives who walked on the treadmill increased their ratings of their husbands' physical and cardiac efficacy to a level equivalent to those of their husbands. Spouses' and patients' perceptions of patients' cardiac capability after treadmill testing and counseling at 3 weeks were significantly correlated with peak treadmill heart rate and workload at 11 and 26 weeks. Efficacy ratings at 3 weeks were slightly better than peak 3-week treadmill heart rate and workload as predictors of treadmill performance at 11 and 26 weeks. Participation in treadmill testing early after acute myocardial infarction is an effective means for reassuring spouses about the capacity of their partners to resume their customary physical activities with safety.

  6. Evaluation of Inferential Performance Through Confidence Bounds for Power Curves

    OpenAIRE

    Amang Sukasih John L Eltinge

    2002-01-01

    In analysis of complex survey data, explores the inferential effects of point estimation bias, variance estimation bias, and variance estimator instability, which can seriously affect the power of a statistical test and the confidence intervals.

  7. Long-term Stability and Reliability of Baseline Cognitive Assessments in High School Athletes Using ImPACT at 1-, 2-, and 3-year Test-Retest Intervals.

    Science.gov (United States)

    Brett, Benjamin L; Smyk, Nathan; Solomon, Gary; Baughman, Brandon C; Schatz, Philip

    2016-08-18

    The ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing) neurocognitive testing battery is a widely used tool used for the assessment and management of sports-related concussion. Research on the stability of ImPACT in high school athletes at a 1- and 2-year intervals have been inconsistent, requiring further investigation. We documented 1-, 2-, and 3-year test-retest reliability of repeated ImPACT baseline assessments in a sample of high school athletes, using multiple statistical methods for examining stability. A total of 1,510 high school athletes completed baseline cognitive testing using online ImPACT test battery at three time periods of approximately 1- (N = 250), 2- (N = 1146), and 3-year (N = 114) intervals. No participant sustained a concussion between assessments. Intraclass correlation coefficients (ICCs) ranged in composite scores from 0.36 to 0.90 and showed little change as intervals between assessments increased. Reliable change indices and regression-based measures (RBMs) examining the test-retest stability demonstrated a lack of significant change in composite scores across the various time intervals, with very few cases (0%-6%) falling outside of 95% confidence intervals. The results suggest ImPACT composites scores remain considerably stability across 1-, 2-, and 3-year test-retest intervals in high school athletes, when considering both ICCs and RBM. Annually ascertaining baseline scores continues to be optimal for ensuring accurate and individualized management of injury for concussed athletes. For instances in which more recent baselines are not available (1-2 years), clinicians should seek to utilize more conservative range estimates in determining the presence of clinically meaningful change in cognitive performance. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. The interval testing procedure: A general framework for inference in functional data analysis.

    Science.gov (United States)

    Pini, Alessia; Vantini, Simone

    2016-09-01

    We introduce in this work the Interval Testing Procedure (ITP), a novel inferential technique for functional data. The procedure can be used to test different functional hypotheses, e.g., distributional equality between two or more functional populations, equality of mean function of a functional population to a reference. ITP involves three steps: (i) the representation of data on a (possibly high-dimensional) functional basis; (ii) the test of each possible set of consecutive basis coefficients; (iii) the computation of the adjusted p-values associated to each basis component, by means of a new strategy here proposed. We define a new type of error control, the interval-wise control of the family wise error rate, particularly suited for functional data. We show that ITP is provided with such a control. A simulation study comparing ITP with other testing procedures is reported. ITP is then applied to the analysis of hemodynamical features involved with cerebral aneurysm pathology. ITP is implemented in the fdatest R package. © 2016, The International Biometric Society.

  9. The effect of a daily quiz (TOPday) on self-confidence, enthusiasm, and test results for biomechanics.

    Science.gov (United States)

    Tanck, Esther; Maessen, Martijn F H; Hannink, Gerjon; van Kuppeveld, Sascha M H F; Bolhuis, Sanneke; Kooloos, Jan G M

    2014-01-01

    Many students in Biomedical Sciences have difficulty understanding biomechanics. In a second-year course, biomechanics is taught in the first week and examined at the end of the fourth week. Knowledge is retained longer if the subject material is repeated. However, how does one encourage students to repeat the subject matter? For this study, we developed 'two opportunities to practice per day (TOPday)', consisting of multiple-choice questions on biomechanics with immediate feedback, which were sent via e-mail. We investigated the effect of TOPday on self-confidence, enthusiasm, and test results for biomechanics. All second-year students (n = 95) received a TOPday of biomechanics on every regular course day with increasing difficulty during the course. At the end of the course, a non-anonymous questionnaire was conducted. The students were asked how many TOPday questions they completed (0-6 questions [group A]; 7-18 questions [group B]; 19-24 questions [group C]). Other questions included the appreciation for TOPday, and increase (no/yes) in self-confidence and enthusiasm for biomechanics. Seventy-eight students participated in the examination and completed the questionnaire. The appreciation for TOPday in group A (n = 14), B (n = 23) and C (n = 41) was 7.0 (95 % CI 6.5-7.5), 7.4 (95 % CI 7.0-7.8), and 7.9 (95 % CI 7.6-8.1), respectively (p biomechanics due to TOPday. In addition, they had a higher test result for biomechanics (p biomechanics on the other.

  10. Oscillatory dynamics of an intravenous glucose tolerance test model with delay interval

    Science.gov (United States)

    Shi, Xiangyun; Kuang, Yang; Makroglou, Athena; Mokshagundam, Sriprakash; Li, Jiaxu

    2017-11-01

    Type 2 diabetes mellitus (T2DM) has become prevalent pandemic disease in view of the modern life style. Both diabetic population and health expenses grow rapidly according to American Diabetes Association. Detecting the potential onset of T2DM is an essential focal point in the research of diabetes mellitus. The intravenous glucose tolerance test (IVGTT) is an effective protocol to determine the insulin sensitivity, glucose effectiveness, and pancreatic β-cell functionality, through the analysis and parameter estimation of a proper differential equation model. Delay differential equations have been used to study the complex physiological phenomena including the glucose and insulin regulations. In this paper, we propose a novel approach to model the time delay in IVGTT modeling. This novel approach uses two parameters to simulate not only both discrete time delay and distributed time delay in the past interval, but also the time delay distributed in a past sub-interval. Normally, larger time delay, either a discrete or a distributed delay, will destabilize the system. However, we find that time delay over a sub-interval might not. We present analytically some basic model properties, which are desirable biologically and mathematically. We show that this relatively simple model provides good fit to fluctuating patient data sets and reveals some intriguing dynamics. Moreover, our numerical simulation results indicate that our model may remove the defect in well known Minimal Model, which often overestimates the glucose effectiveness index.

  11. Prognostic value of QTc interval dispersion changes during exercise testing in hypertensive men

    Directory of Open Access Journals (Sweden)

    Đorđević Dragan

    2008-01-01

    Full Text Available INTRODUCTION The prognostic significance of QTc dispersion changes during exercise testing (ET in patients with left ventricular hypertrophy is not clear. OBJECTIVE The aim was to study the dynamics of QTc interval dispersion (QTcd in patients (pts with left ventricular hypertrophy (LVH during the exercise testing and its prognostic significance. METHOD In the study we included 55 men (aged 53 years with hypertensive left ventricular hypertrophy and a negative ET (LVH group, 20 men (aged 58 years with a positive ET and 20 healthy men (aged 55 years. There was no statistically significant difference in the left ventricular mass index (LVMI between LVH group and ILVH group (160.9±14.9 g/m2 and 152.8±22.7 g/m2. The first ECG was done before the ET and the second one was done during the first minute of recovery, with calculation of QTc dispersion. The patients were followed during five years for new cardiovascular events. RESULTS During the ET, the QTcd significantly increased in LVH group (56.8±18.0 - 76.7±22.6 ms; p<0.001. A statistically significant correlation was found between the amount of ST segment depression at the end of ET and QTc dispersion at the beginning and at the end of ET (r=0.673 and r=0.698; p<0.01. The QTc dispersion was increased in 35 (63.6% patients and decreased in 20 (36.4% patients during the ET. Three patients (5.4% in the first group had adverse cardiovascular events during the five-year follow-up. A multiple stepwise regression model was formed by including age, LVMI, QTc interval, QTc dispersion and change of QTc dispersion during the ET. There was no prognostic significance of QTc interval and QTc dispersion during five-year follow-up in regard to adverse cardiovascular events, but prognostic value was found for LVMI (coefficient β=0.480; p<0.001. CONCLUSION The increase of QTc interval dispersion is common in men with positive ET for myocardial ischemia and there is a correlation between QTc dispersion and

  12. Development and interval testing of a naturalistic driving methodology to evaluate driving behavior in clinical research

    Science.gov (United States)

    Babulal, Ganesh M.; Addison, Aaron; Ghoshal, Nupur; Stout, Sarah H.; Vernon, Elizabeth K.; Sellan, Mark; Roe, Catherine M.

    2016-01-01

    Background: The number of older adults in the United States will double by 2056. Additionally, the number of licensed drivers will increase along with extended driving-life expectancy. Motor vehicle crashes are a leading cause of injury and death in older adults. Alzheimer’s disease (AD) also negatively impacts driving ability and increases crash risk. Conventional methods to evaluate driving ability are limited in predicting decline among older adults. Innovations in GPS hardware and software can monitor driving behavior in the actual environments people drive in. Commercial off-the-shelf (COTS) devices are affordable, easy to install and capture large volumes of data in real-time. However, adapting these methodologies for research can be challenging. This study sought to adapt a COTS device and determine an interval that produced accurate data on the actual route driven for use in future studies involving older adults with and without AD.  Methods: Three subjects drove a single course in different vehicles at different intervals (30, 60 and 120 seconds), at different times of day, morning (9:00-11:59AM), afternoon (2:00-5:00PM) and night (7:00-10pm). The nine datasets were examined to determine the optimal collection interval. Results: Compared to the 120-second and 60-second intervals, the 30-second interval was optimal in capturing the actual route driven along with the lowest number of incorrect paths and affordability weighing considerations for data storage and curation. Discussion: Use of COTS devices offers minimal installation efforts, unobtrusive monitoring and discreet data extraction.  However, these devices require strict protocols and controlled testing for adoption into research paradigms.  After reliability and validity testing, these devices may provide valuable insight into daily driving behaviors and intraindividual change over time for populations of older adults with and without AD.  Data can be aggregated over time to look at changes or

  13. Conducting thermomechanical fatigue test in air at light water reactor relevant temperature intervals

    Energy Technology Data Exchange (ETDEWEB)

    Ramesh, Mageshwaran [Paul Scherrer Institute, Laboratory for Nuclear Materials, CH-5232 Villigen-PSI (Switzerland); Leber, Hans J., E-mail: hans.leber@psi.ch [Paul Scherrer Institute, Laboratory for Nuclear Materials, CH-5232 Villigen-PSI (Switzerland); Diener, Markus; Spolenak, Ralph [Laboratory for Nanometallurgy, Department of Materials, ETH Zuerich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich (Switzerland)

    2011-08-01

    In Light Water Reactors (LWR), many structural components are made of austenitic stainless steels (SS). These components are subject to extreme conditions, such as large temperature gradients and pressure loads during service. Hence, the fatigue and fracture behavior of austenitic SS under these conditions has evoked consistent interest over the years. Most studies dealing with this problem in the past, investigated the isothermal fatigue (IF) condition, which is not the case in the service, and less attention has been paid to thermomechanical fatigue (TMF). Moreover, the existing codes of practice and standards for TMF testing are mainly derived from the high temperature TMF tests (T{sub mean} > 400 deg. C). This work presents the development of a facility to perform TMF tests under LWR relevant temperature interval in air. The realized testing parameters and tolerances are compared with the recommendations of existing codes of practice and standards from high temperature tests. The effectiveness of the testing facility was verified with series of TMF and IF tests performed on specimens made out of a commercial austenitic SS TP347 pipe material. The results revealed that the existing tolerances in standards are quite strict for the application of lower temperature ranges TMF tests. It was found that the synchronous, in-phase (IP) TMF tested specimens possess a higher lifetime than those subjected to the asynchronous, out-of-phase (OP) TMF and IF at T{sub max} in the investigated strain range for austenitic SS. Nevertheless, the fatigue lifetime of all the test conditions was similar in the engineering scale.

  14. Effectiveness of a computerized alert system based on re-testing intervals for limiting the inappropriateness of laboratory test requests.

    Science.gov (United States)

    Lippi, Giuseppe; Brambilla, Marco; Bonelli, Patrizia; Aloe, Rosalia; Balestrino, Antonio; Nardelli, Anna; Ceda, Gian Paolo; Fabi, Massimo

    2015-11-01

    There is consolidated evidence that the burden of inappropriate laboratory test requests is very high, up to 70%. We describe here the function of a computerized alert system linked to the order entry, designed to limit the number of potentially inappropriate laboratory test requests. A computerized alert system based on re-testing intervals and entailing the generation of pop-up alerts when preset criteria of appropriateness for 15 laboratory tests were violated was implemented in two clinical wards of the University Hospital of Parma. The effectiveness of the system for limiting potentially inappropriate tests was monitored for 6months. Overall, 765/3539 (22%) test requests violated the preset criteria of appropriateness and generated the appearance of electronic alert. After alert appearance, 591 requests were annulled (17% of total tests requested and 77% of tests alerted, respectively). The total number of test requests violating the preset criteria of inappropriateness constantly decreased over time (26% in the first three months of implementation versus 17% in the following period; prequests, generating significant economic saving and educating physicians to a more efficient use of laboratory resources. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  15. Are Confidence Ratings Test- or Trait-Driven? Individual Differences among High, Average, and Low Comprehenders in Fourth Grade

    Science.gov (United States)

    Kasperski, Ronen; Katzir, Tami

    2013-01-01

    The aim of this study was to examine whether low, average, and high comprehenders (LC, AC, and HC, respectively) differed in their reading self-confidence and bias ratings, and whether confidence ratings were driven by reading ability or distributed evenly among diverse readers. Seventy fourth-graders with good decoding abilities were administered…

  16. The Underground Test Area Project of the Nevada Test Site: Building Confidence in Groundwater Flow and Transport Models at Pahute Mesa Through Focused Characterization Studies

    Energy Technology Data Exchange (ETDEWEB)

    Pawloski, G A; Wurtz, J; Drellack, S L

    2009-12-29

    Pahute Mesa at the Nevada Test Site contains about 8.0E+07 curies of radioactivity caused by underground nuclear testing. The Underground Test Area Subproject has entered Phase II of data acquisition, analysis, and modeling to determine the risk to receptors from radioactivity in the groundwater, establish a groundwater monitoring network, and provide regulatory closure. Evaluation of radionuclide contamination at Pahute Mesa is particularly difficult due to the complex stratigraphy and structure caused by multiple calderas in the Southwestern Nevada Volcanic Field and overprinting of Basin and Range faulting. Included in overall Phase II goals is the need to reduce the uncertainty and improve confidence in modeling results. New characterization efforts are underway, and results from the first year of a three-year well drilling plan are presented.

  17. The Effect of Retention Interval Task Difficulty on Young Children's Prospective Memory: Testing the Intention Monitoring Hypothesis

    Science.gov (United States)

    Mahy, Caitlin E. V.; Moses, Louis J.

    2015-01-01

    The current study examined the impact of retention interval task difficulty on 4- and 5-year-olds' prospective memory (PM) to test the hypothesis that children periodically monitor their intentions during the retention interval and that disrupting this monitoring may result in poorer PM performance. In addition, relations among PM, working memory,…

  18. Risk-Based Allowed Outage Time and Surveillance Test Interval Extensions for Angra 1

    Directory of Open Access Journals (Sweden)

    Sonia M. Orlando Gibelli

    2012-01-01

    Full Text Available In this work, Probabilistic Safety Assessment (PSA is used to evaluate Allowed Outage Times (AOT and Surveillance Test Intervals (STI extensions for three Angra 1 nuclear power plant safety systems. The interest in such an analysis lies on the fact that PSA comprises a risk-based tool for safety evaluation and has been increasingly applied to support both the regulatory and the operational decision-making processes. Regarding Angra 1, among other applications, PSA is meant to be an additional method that can be used by the utility to justify Technical Specification relaxation to the Brazilian regulatory body. The risk measure used in this work is the Core Damage Frequency, obtained from the Angra 1 Level 1 PSA study. AOT and STI extensions are evaluated for the Safety Injection, Service Water and Auxiliary Feedwater Systems using the SAPHIRE code. In order to compensate for the risk increase caused by the extensions, compensatory measures as (1 test of redundant train prior to entering maintenance and (2 staggered test strategy are proposed. Results have shown that the proposed AOT extensions are acceptable for two of the systems with the implementation of compensatory measures whereas STI extensions are acceptable for all three systems.

  19. The Model Confidence Set

    DEFF Research Database (Denmark)

    Hansen, Peter Reinhard; Lunde, Asger; Nason, James M.

    acknowledges the limitations of the data, such that uninformative data yields a MCS with many models, whereas informative data yields a MCS with only a few models. The MCS procedure does not assume that a particular model is the true model, in fact theMCS procedure can be used to comparemore general objects......The paper introduces the model confidence set (MCS) and applies it to the selection of models. A MCS is a set of models that is constructed such that it will contain the best model with a given level of confidence. The MCS is in this sense analogous to a confidence interval for a parameter. The MCS......, beyond the comparison of models. We apply the MCS procedure to two empirical problems. First, we revisit the inflation forecasting problem posed by Stock and Watson (1999), and compute the MCS for their set of inflation forecasts. Second, we compare a number of Taylor rule regressions and determine...

  20. Flight Crew Survey Responses from the Interval Management (IM) Avionics Phase 2 Flight Test

    Science.gov (United States)

    Baxley, Brian T.; Swieringa, Kurt A.; Wilson, Sara R.; Roper, Roy D.; Hubbs, Clay E.; Goess, Paul A.; Shay, Richard F.

    2017-01-01

    The Interval Management (IM) Avionics Phase 2 flight test used three aircraft over a nineteen day period to operationally evaluate a prototype IM avionics. Quantitative data were collected on aircraft state data and IM spacing algorithm performance, and qualitative data were collected through end-of-scenario and end-of-day flight crew surveys. The majority of the IM operations met the performance goals established for spacing accuracy at the Achieve-by Point and the Planned Termination Point, however there were operations that did not meet goals for a variety of reasons. While the positive spacing accuracy results demonstrate the prototype IM avionics can contribute to the overall air traffic goal, critical issues were also identified that need to be addressed to enhance IM performance. The first category was those issues that impacted the conduct and results of the flight test, but are not part of the IM concept or procedures. These included the design of arrival and approach procedures was not ideal to support speed as the primary control mechanism, the ground-side of the Air Traffic Management Technology Demonstration (ATD-1) integrated concept of operations was not part of the flight test, and the high workload to manually enter the information required to conduct an IM operation. The second category was issues associated with the IM spacing algorithm or flight crew procedures. These issues include the high frequency of IM speed changes and reversals (accelerations), a mismatch between the deceleration rate used by the spacing algorithm and the actual aircraft performance, and some spacing error calculations were sensitive to normal operational variations in aircraft airspeed or altitude which triggered additional IM speed changes. Once the issues in these two categories are addressed, the future IM avionics should have considerable promise supporting the goals of improving system throughput and aircraft efficiency.

  1. Fast & Confident Probabilistic Categorization

    OpenAIRE

    Goutte, Cyril

    2007-01-01

    We describe NRC's submission to the Anomaly Detection/Text Mining competition organised at the Text Mining Workshop 2007. This submission relies on a straightforward implementation of the probabilistic categoriser described in (Gaussier et al., ECIR'02). This categoriser is adapted to handle multiple labelling and a piecewise-linear confidence estimation layer is added to provide an estimate of the labelling confidence. This technique achieves a score of 1.689 on the test data.

  2. Clinimetric properties of the Tinetti Mobility Test, Four Square Step Test, Activities-specific Balance Confidence Scale, and spatiotemporal gait measures in individuals with Huntington's disease.

    Science.gov (United States)

    Kloos, Anne D; Fritz, Nora E; Kostyk, Sandra K; Young, Gregory S; Kegelmeyer, Deb A

    2014-09-01

    Individuals with Huntington's disease (HD) experience balance and gait problems that lead to falls. Clinicians currently have very little information about the reliability and validity of outcome measures to determine the efficacy of interventions that aim to reduce balance and gait impairments in HD. This study examined the reliability and concurrent validity of spatiotemporal gait measures, the Tinetti Mobility Test (TMT), Four Square Step Test (FSST), and Activities-specific Balance Confidence (ABC) Scale in individuals with HD. Participants with HD [n = 20; mean age ± SD=50.9 ± 13.7; 7 male] were tested on spatiotemporal gait measures and the TMT, FSST, and ABC Scale before and after a six week period to determine test-retest reliability and minimal detectable change (MDC) values. Linear relationships between gait and clinical measures were estimated using Pearson's correlation coefficients. Spatiotemporal gait measures, the TMT total and the FSST showed good to excellent test-retest reliability (ICC > 0.75). MDC values were 0.30 m/s and 0.17 m/s for velocity in forward and backward walking respectively, four points for the TMT, and 3s for the FSST. The TMT and FSST were highly correlated with most spatiotemporal measures. The ABC Scale demonstrated lower reliability and less concurrent validity than other measures. The high test-retest reliability over a six week period and concurrent validity between the TMT, FSST, and spatiotemporal gait measures suggest that the TMT and FSST may be useful outcome measures for future intervention studies in ambulatory individuals with HD. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Gait in children with cerebral palsy : observer reliability of Physician Rating Scale and Edinburgh Visual Gait Analysis Interval Testing scale

    NARCIS (Netherlands)

    Maathuis, KGB; van der Schans, CP; van Iperen, A; Rietman, HS; Geertzen, JHB

    2005-01-01

    The aim of this study was to test the inter- and intra-observer reliability of the Physician Rating Scale (PRS) and the Edinburgh Visual Gait Analysis Interval Testing (GAIT) scale for use in children with cerebral palsy (CP). Both assessment scales are quantitative observational scales, evaluating

  4. Quality specifications for the extra-analytical phase of laboratory testing: Reference intervals and decision limits.

    Science.gov (United States)

    Ceriotti, Ferruccio

    2017-07-01

    Reference intervals and decision limits are a critical part of the clinical laboratory report. The evaluation of their correct use represents a tool to verify the post analytical quality. Four elements are identified as indicators. 1. The use of decision limits for lipids and glycated hemoglobin. 2. The use, whenever possible, of common reference values. 3. The presence of gender-related reference intervals for at least the following common serum measurands (besides obviously the fertility relate hormones): alkaline phosphatase (ALP), alanine aminotransferase (ALT), creatine kinase (CK), creatinine, gamma-glutamyl transferase (GGT), IgM, ferritin, iron, transferrin, urate, red blood cells (RBC), hemoglobin (Hb) and hematocrit (Hct). 4. The presence of age-related reference intervals. The problem of specific reference intervals for elderly people is discussed, but their use is not recommended; on the contrary it is necessary the presence of pediatric age-related reference intervals at least for the following common serum measurands: ALP, amylase, creatinine, inorganic phosphate, lactate dehydrogenase, aspartate aminotransferase, urate, insulin like growth factor 1, white blood cells, RBC, Hb, Hct, alfa-fetoprotein and fertility related hormones. The lack of such reference intervals may imply significant risks for the patients. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  5. Interval Colorectal Cancers following Guaiac Fecal Occult Blood Testing in the Ontario ColonCancerCheck Program

    Directory of Open Access Journals (Sweden)

    Lawrence Paszat

    2016-01-01

    Full Text Available Background. This work examines the occurrence of interval colorectal cancers (CRCs in the Ontario ColonCancerCheck (CCC program. We define interval CRC as CRC diagnosed within 2 years following normal guaiac fecal occult blood testing (gFOBT. Methods. Persons aged 50–74 who completed a baseline CCC gFOBT kit in 2008 and 2009, without a prior history of CRC, or recent colonoscopy, flexible sigmoidoscopy, or gFOBT, were identified. Rates of CRC following positive and normal results at baseline and subsequent gFOBT screens were computed and overall survival was compared between those following positive and normal results. Results. Interval CRC was diagnosed within 24 months following the baseline screen among 0.16% of normals and following the subsequent screen among 0.18% of normals. Interval cancers comprised 38.70% of CRC following the baseline screen and 50.86% following the subsequent screen. Adjusting for age and sex, the hazard ratio (HR for death following interval cancer compared to CRC following positive result was 1.65 (1.32, 2.05 following the first screen and 1.71 (1.00, 2.91 following the second screen. Conclusion. Interval CRCs following gFOBT screening comprise a significant proportion of CRC diagnosed within 2 years after gFOBT testing and are associated with a higher risk of death.

  6. Interval Colorectal Cancers following Guaiac Fecal Occult Blood Testing in the Ontario ColonCancerCheck Program.

    Science.gov (United States)

    Paszat, Lawrence; Sutradhar, Rinku; Tinmouth, Jill; Baxter, Nancy; Rabeneck, Linda

    2016-01-01

    Background. This work examines the occurrence of interval colorectal cancers (CRCs) in the Ontario ColonCancerCheck (CCC) program. We define interval CRC as CRC diagnosed within 2 years following normal guaiac fecal occult blood testing (gFOBT). Methods. Persons aged 50-74 who completed a baseline CCC gFOBT kit in 2008 and 2009, without a prior history of CRC, or recent colonoscopy, flexible sigmoidoscopy, or gFOBT, were identified. Rates of CRC following positive and normal results at baseline and subsequent gFOBT screens were computed and overall survival was compared between those following positive and normal results. Results. Interval CRC was diagnosed within 24 months following the baseline screen among 0.16% of normals and following the subsequent screen among 0.18% of normals. Interval cancers comprised 38.70% of CRC following the baseline screen and 50.86% following the subsequent screen. Adjusting for age and sex, the hazard ratio (HR) for death following interval cancer compared to CRC following positive result was 1.65 (1.32, 2.05) following the first screen and 1.71 (1.00, 2.91) following the second screen. Conclusion. Interval CRCs following gFOBT screening comprise a significant proportion of CRC diagnosed within 2 years after gFOBT testing and are associated with a higher risk of death.

  7. The discriminative power of the Interval Shuttle Run Test and the Maximal Multistage Shuttle Run Test for playing level of soccer

    NARCIS (Netherlands)

    Lemmink, K.A.P.M.; Verheijen, R.; Visscher, C.

    2004-01-01

    AIM: The purpose of this study was to examine the discriminative power of the recently developed Interval Shuttle Run Test (ISRT) and the widely used Maximal Multistage 20 m Shuttle Run Test (MMSRT) for soccer players at different levels of competition. The main difference between the tests is that

  8. Self-care confidence may be more important than cognition to influence self-care behaviors in adults with heart failure: Testing a mediation model.

    Science.gov (United States)

    Vellone, Ercole; Pancani, Luca; Greco, Andrea; Steca, Patrizia; Riegel, Barbara

    2016-08-01

    Cognitive impairment can reduce the self-care abilities of heart failure patients. Theory and preliminary evidence suggest that self-care confidence may mediate the relationship between cognition and self-care, but further study is needed to validate this finding. The aim of this study was to test the mediating role of self-care confidence between specific cognitive domains and heart failure self-care. Secondary analysis of data from a descriptive study. Three out-patient sites in Pennsylvania and Delaware, USA. A sample of 280 adults with chronic heart failure, 62 years old on average and mostly male (64.3%). Data on heart failure self-care and self-care confidence were collected with the Self-Care of Heart Failure Index 6.2. Data on cognition were collected by trained research assistants using a neuropsychological test battery measuring simple and complex attention, processing speed, working memory, and short-term memory. Sociodemographic data were collected by self-report. Clinical information was abstracted from the medical record. Mediation analysis was performed with structural equation modeling and indirect effects were evaluated with bootstrapping. Most participants had at least 1 impaired cognitive domain. In mediation models, self-care confidence consistently influenced self-care and totally mediated the relationship between simple attention and self-care and between working memory and self-care (comparative fit index range: .929-.968; root mean squared error of approximation range: .032-.052). Except for short-term memory, which had a direct effect on self-care maintenance, the other cognitive domains were unrelated to self-care. Self-care confidence appears to be an important factor influencing heart failure self-care even in patients with impaired cognition. As few studies have successfully improved cognition, interventions addressing confidence should be considered as a way to improve self-care in this population. Copyright © 2016 Elsevier Ltd. All

  9. Human error considerations and annunciator effects in determining optimal test intervals for periodically inspected standby systems

    Energy Technology Data Exchange (ETDEWEB)

    McWilliams, T.P.; Martz, H.F.

    1981-01-01

    This paper incorporates the effects of four types of human error in a model for determining the optimal time between periodic inspections which maximizes the steady state availability for standby safety systems. Such safety systems are characteristic of nuclear power plant operations. The system is modeled by means of an infinite state-space Markov chain. Purpose of the paper is to demonstrate techniques for computing steady-state availability A and the optimal periodic inspection interval tau* for the system. The model can be used to investigate the effects of human error probabilities on optimal availability, study the benefits of annunciating the standby-system, and to determine optimal inspection intervals. Several examples which are representative of nuclear power plant applications are presented.

  10. Raising Confident Kids

    Science.gov (United States)

    ... follow some general guidelines to build kids' confidence. Self-confidence rises out of a sense of competence. In ... into that high-octane fuel of confidence. Building self-confidence can begin very early. When babies learn to ...

  11. Exploration of Analysis Methods for Diagnostic Imaging Tests: Problems with ROC AUC and Confidence Scores in CT Colonography

    OpenAIRE

    Susan Mallett; Steve Halligan; Collins, Gary S.; Altman, Doug G

    2014-01-01

    BACKGROUND: Different methods of evaluating diagnostic performance when comparing diagnostic tests may lead to different results. We compared two such approaches, sensitivity and specificity with area under the Receiver Operating Characteristic Curve (ROC AUC) for the evaluation of CT colonography for the detection of polyps, either with or without computer assisted detection. METHODS: In a multireader multicase study of 10 readers and 107 cases we compared sensitivity and specificity, using ...

  12. Effects of an intensive clinical skills course on senior nursing students' self-confidence and clinical competence: A quasi-experimental post-test study.

    Science.gov (United States)

    Park, Soohyun

    2018-02-01

    To foster nursing professionals, nursing education requires the integration of knowledge and practice. Nursing students in their senior year experience considerable stress in performing the core nursing skills because, typically, they have limited opportunities to practice these skills in their clinical practicum. Therefore, nurse educators should revise the nursing curricula to focus on core nursing skills. To identify the effect of an intensive clinical skills course for senior nursing students on their self-confidence and clinical competence. A quasi-experimental post-test study. A university in South Korea during the 2015-2016 academic year. A convenience sample of 162 senior nursing students. The experimental group (n=79) underwent the intensive clinical skills course, whereas the control group (n=83) did not. During the course, students repeatedly practiced the 20 items that make up the core basic nursing skills using clinical scenarios. Participants' self-confidence in the core clinical nursing skills was measured using a 10-point scale, while their clinical competence with these skills was measured using the core clinical nursing skills checklist. Independent t-test and chi-square tests were used to analyze the data. The mean scores in self-confidence and clinical competence were higher in the experimental group than in the control group. This intensive clinical skills courses had a positive effect on senior nursing students' self-confidence and clinical competence for the core clinical nursing skills. This study emphasizes the importance of reeducation using a clinical skills course during the transition from student to nursing professional. Copyright © 2017. Published by Elsevier Ltd.

  13. Network autocorrelation modeling : A Bayes factor approach for testing (multiple) precise and interval hypotheses

    NARCIS (Netherlands)

    Dittrich, D.; Leenders, R.T.A.J.; Mulder, J.

    2017-01-01

    Currently available (classical) testing procedures for the network autocorrelation can only be used for falsifying a precise null hypothesis of no network effect. Classical methods can neither be used for quantifying evidence for the null nor for testing multiple hypotheses simultaneously. This

  14. Network autocorrelation modeling : A Bayes factor approach for testing (multiple) precise and interval hypotheses

    NARCIS (Netherlands)

    Dittrich, D.; Leenders, R.T.A.J.; Mulder, J.

    2018-01-01

    Currently available (classical) testing procedures for the network autocorrelation can only be used for falsifying a precise null hypothesis of no network effect. Classical methods can be neither used for quantifying evidence for the null nor for testing multiple hypotheses simultaneously. This

  15. Practice Effects and Stability of Neuropsychological and UHDRS Tests Over Short Retest Intervals in Huntington Disease.

    Science.gov (United States)

    Beglinger, Leigh J; Adams, William H; Fiedorowicz, Jess G; Duff, Kevin; Langbehn, Douglas; Biglan, Kevin; Caviness, John; Olson, Blair; Paulsen, Jane S

    2015-01-01

    In Huntington disease (HD), cognitive changes due to disease-progression or treatment are potentially confounded by "practice effects" (PE)--performance improvement from prior exposure to test materials. A practice run-in ("dual baseline") was used in an HD cognitive trial to determine if PE could be minimized and evaluate performance trajectories over multiple visits. Non-depressed adults (N = 36) with mild to moderate HD-related cognitive deficits participated in a clinical trial to examine the efficacy of citalopram to enhance cognition. Cognitive tests were administered at three visits (2 weeks separating each visit), before active treatment randomization. Some tests were also administered at screening. Therefore 3-4 pre-treatment repetitions were available. We examined test improvement using repeated-measures ANOVAs with planned pairwise comparisons. Despite the practice run-in and use of alternate test forms, results indicated ongoing improvements over at least three test sessions on all three UHDRS cognitive tests. Trails A and B showed improvements between the third and fourth session, which suggests that one pre-baseline visit may not be effective in reducing practice on this important and commonly used test. Overall, 7 out of 13 variables showed some degree of short-term PE, even after multiple sessions and alternate forms. Tests assessing processing speed and memory may be particularly confounded by ongoing PE across at least 2-3 sessions. Practice run-in periods and alternate forms may help minimize the impact of such effects in HD clinical trials but awareness of which tests are most susceptible to PE is important in clinical trial design.

  16. Improving Statistical Rigor in Defense Test and Evaluation: Use of Tolerance Intervals in Designed Experiments

    Science.gov (United States)

    2014-10-01

    Polytechnic Institute and State University, Naval Postgraduate School, and the Air Force Institute of Technology (AFIT). The consortium’s overall research...University http://www.dau.mil 21 Defense ARJ, October 2014, Vol. 21 No. 4 : 804–824 References Air Force Institute of Technology. (2012). Science of test...evaluation (T&E) (ATEC Policy Bulletin 3-12). Aberdeen Proving Ground, MD: Author. Department of Defense. (2012). Scientific test and analysis techniques

  17. The effect of the inter-phase delay interval in the spontaneous object recognition test for pigs

    DEFF Research Database (Denmark)

    Kornum, Birgitte Rahbek; Thygesen, Kristin Sjølie; Nielsen, Thomas Rune

    2007-01-01

    In the neuroscience community interest for using the pig is growing. Several disease models have been developed creating a need for validation of behavioural paradigms in these animals. Here, we report the effect of different inter-phase delay intervals on the performance of Göttingen minipigs...... in the spontaneous object recognition test. The test consisted of a sample and a test phase. First, the pigs explored two similar objects. After a 10-min, 1-h, or 24-h delay two different objects were presented; one familiar from the sample phase and one novel. An exploration-time difference between the novel...... in our set-up of the spontaneous object recognition test. After a 1-h delay, the pigs still showed a significant habituation to the familiar object, but no discrimination was observed. Discrimination between the two objects was mainly confined to the first half of the test phase, and we observed a high...

  18. Prognostic ability of VE/VCO2 slope calculations using different exercise test time intervals in subjects with heart failure.

    Science.gov (United States)

    Arena, Ross; Humphrey, Reed; Peberdy, Mary Ann

    2003-12-01

    The minute ventilation-carbon dioxide production (VE/VCO2) slope, obtained during exercise testing, possesses prognostic value in heart failure (HF). The VE-VCO2 relationship is generally linear thereby hypothetically producing similar slope values regardless of the exercise-test time interval used for calculation. This study assesses the ability of the VE/VCO2 slope, calculated at different time intervals throughout a progressive exercise test, to predict 1-year cardiac-related hospitalization and mortality in subjects with HF. Seventy-two subjects underwent symptom-limited exercise testing with ventilatory expired gas analysis. Mean age and left ventricular ejection fraction for 44 male and 28 female subjects were 51.2 years (+/-13.0) and 27.0% (+/-12.3) respectively. The VE/VCO2 slope was calculated from time 0 to 25, 50, 75 and 100% of exercise time and subsequently used to create five randomly selected VE/VCO2 slope categories. (The intraclass correlation coefficient found calculation of the VE/VCO2 slope, when divided into quartiles, to be a reliable measure (alpha=0.94, Pslope categories (25-100% and random selections) were significant predictors of cardiac-related hospitalization and mortality over a 1-year period. Multivariate Cox regression analysis revealed all VE/VCO2 slope categories outperformed peak oxygen consumption (VO2) in predicting hospitalization and mortality at 1 year. Although the different classification schemes were not identical, these results suggest VE/VCO2 slope maintains prognostic significance regardless of exercise-test time interval. Calculation of VE/VCO2 slope may therefore still be valuable in subjects putting forth a sub-maximal effort while effort-dependent measures, such as peak VO2, are not.

  19. The 30-15 intermittent fitness test: accuracy for individualizing interval training of young intermittent sport players.

    Science.gov (United States)

    Buchheit, Martin

    2008-03-01

    The objective of this study was to gather evidence supporting the accuracy of the 30-15 Intermittent Fitness Test (30-15IFT) for individualizing interval training of young intermittent sport players. In 59 young intermittent sport players (age, 16.2 +/- 2.3 years), we observed the relationships between the maximal running speed (MRS) reached at the end of the 30-15IFT (MRS30-15IFT) and physiological variables elicited by shuttle intermittent runs, including maximal oxygen uptake, explosive power of lower limbs, and the ability to repeat intense exercise bouts through cardiorespiratory recovery kinetics during exercise. To observe the capacity of the 30-15IFT to prescribe suitable running intensities for interval training sessions, we compared heart rates (HRs) reached during 3 series of intermittent runs, where distances were set according to the MRS30-15IFT and to MRS reached with 2 popular continuous field tests: the University of Montreal track test and the 20-m shuttle run test. The results show that the MRS30-15IFT is significantly correlated with all physiological variables elicited by shuttle intermittent runs (P intermittent runs, HR recorded during the runs based on MRS30-15IFT presented significantly less interindividual variation than when the continuously determined MRS were used as reference speeds. In conclusion, we can say that the 30-15IFT leads to an MRS that simultaneously takes into account various physiological qualities elicited when performing shuttle intermittent runs. For scheduling interval training sessions, the MRS30-15IFT appears to be an accurate reference speed for getting players with different physiological profiles to a similar level of cardiorespiratory demand and thus for standardizing training content.

  20. How to learn effectively in medical school: test yourself, learn actively, and repeat in intervals.

    Science.gov (United States)

    Augustin, Marc

    2014-06-01

    Students in medical school often feel overwhelmed by the excessive amount of factual knowledge they are obliged to learn. Although a large body of research on effective learning methods is published, scientifically based learning strategies are not a standard part of the curriculum in medical school. Students are largely unaware of how to learn successfully and improve memory. This review outlines three fundamental methods that benefit learning: the testing effect, active recall, and spaced repetition. The review summarizes practical learning strategies to learn effectively and optimize long-term retention of factual knowledge.

  1. Pacemaker patients’ perspective and experiences in a pacemaker outpatient clinic in relation to test intervals of the pacemaker

    DEFF Research Database (Denmark)

    Lauberg, Astrid; Hansen, Tina; Pedersen, Trine Pernille Dahl

    . In Aalborg University Hospital pacemakers are tested when implanted, 3 months later and then two years after the implantation. It is tested by a nurse specialist who also is interested in the patient’s general health status and well being. Patient expectations are unknown. Cheng et al (2002) have found...... an evident decline in quality of life regarding psychological and social aspects 6 month after the implantation in terms of cognitive function, work ability, and sexual activity. Mlynarski et al (2009) have found correlations between pacemaker implantation and anxiety and depression. Aim The aim...... the patients expect the nurses to check the technicalities of the pacemaker and talk about precautions. Long test intervals led to worry that the pacemaker was still working. The patients did not expect specialists to pay attention to psychological reactions as they did not find a correlation between...

  2. A study on assessment methodology of surveillance test interval and allowed outage time

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Chang Hyun; You, Young Woo; Cho, Jae Seon; Huh, Chang Wook; Kim, Do Hyoung; Kim, Ju Youl; Kim, Yoon Ik; Yang, Hui Chang; Park, Kang Min [Seoul National Univ., Seoul (Korea, Republic of)

    1998-03-15

    The objectives of this study is the development of methodology by which assesses the optimization of Surveillance Test Internal(STI) and Allowed Outage Time(AOT) using PSA method that can supplement the current deterministic methods and the improvement of Korean nuclear power plant safety. In this study, the survey about the assessment methodologies, modelings and results performed by domestic and international researches are performed as the basic step before developing the assessment methodology of this study. The assessment methodology that supplement the revealed problems in many other studies is presented and the application of new methodology into the example system assures the feasibility of this method. The sensitivity analyses about the failure factors of the components are performed in the bases of the and AOT is quantified. And the reliability assessment methodology about the diesel generator is reviewed and applied to the PSA code. The qualitative assessment for the STI/AOR of RPS/ESFAS assured safety the most important system in the nuclear power plant are performed.

  3. Peak oxygen uptake in a sprint interval testing protocol vs. maximal oxygen uptake in an incremental testing protocol and their relationship with cross-country mountain biking performance.

    Science.gov (United States)

    Hebisz, Rafał; Hebisz, Paulina; Zatoń, Marek; Michalik, Kamil

    2017-04-01

    In the literature, the exercise capacity of cyclists is typically assessed using incremental and endurance exercise tests. The aim of the present study was to confirm whether peak oxygen uptake (V̇O2peak) attained in a sprint interval testing protocol correlates with cycling performance, and whether it corresponds to maximal oxygen uptake (V̇O2max) determined by an incremental testing protocol. A sample of 28 trained mountain bike cyclists executed 3 performance tests: (i) incremental testing protocol (ITP) in which the participant cycled to volitional exhaustion, (ii) sprint interval testing protocol (SITP) composed of four 30 s maximal intensity cycling bouts interspersed with 90 s recovery periods, (iii) competition in a simulated mountain biking race. Oxygen uptake, pulmonary ventilation, work, and power output were measured during the ITP and SITP with postexercise blood lactate and hydrogen ion concentrations collected. Race times were recorded. No significant inter-individual differences were observed in regards to any of the ITP-associated variables. However, 9 individuals presented significantly increased oxygen uptake, pulmonary ventilation, and work output in the SITP compared with the remaining cyclists. In addition, in this group of 9 cyclists, oxygen uptake in SITP was significantly higher than in ITP. After the simulated race, this group of 9 cyclists achieved significantly better competition times (99.5 ± 5.2 min) than the other cyclists (110.5 ± 6.7 min). We conclude that mountain bike cyclists who demonstrate higher peak oxygen uptake in a sprint interval testing protocol than maximal oxygen uptake attained in an incremental testing protocol demonstrate superior competitive performance.

  4. Effects of Cracking Test Conditions on Estimation Uncertainty for Weibull Parameters Considering Time-Dependent Censoring Interval

    Directory of Open Access Journals (Sweden)

    Jae Phil Park

    2016-12-01

    Full Text Available It is extremely difficult to predict the initiation time of cracking due to a large time spread in most cracking experiments. Thus, probabilistic models, such as the Weibull distribution, are usually employed to model the initiation time of cracking. Therefore, the parameters of the Weibull distribution are estimated from data collected from a cracking test. However, although the development of a reliable cracking model under ideal experimental conditions (e.g., a large number of specimens and narrow censoring intervals could be achieved in principle, it is not straightforward to quantitatively assess the effects of the ideal experimental conditions on model estimation uncertainty. The present study investigated the effects of key experimental conditions, including the time-dependent effect of the censoring interval length, on the estimation uncertainties of the Weibull parameters through Monte Carlo simulations. The simulation results provided quantified estimation uncertainties of Weibull parameters in various cracking test conditions. Hence, it is expected that the results of this study can offer some insight for experimenters developing a probabilistic crack initiation model by performing experiments.

  5. Effects of Cracking Test Conditions on Estimation Uncertainty for Weibull Parameters Considering Time-Dependent Censoring Interval.

    Science.gov (United States)

    Park, Jae Phil; Park, Chanseok; Cho, Jongweon; Bahn, Chi Bum

    2016-12-23

    It is extremely difficult to predict the initiation time of cracking due to a large time spread in most cracking experiments. Thus, probabilistic models, such as the Weibull distribution, are usually employed to model the initiation time of cracking. Therefore, the parameters of the Weibull distribution are estimated from data collected from a cracking test. However, although the development of a reliable cracking model under ideal experimental conditions (e.g., a large number of specimens and narrow censoring intervals) could be achieved in principle, it is not straightforward to quantitatively assess the effects of the ideal experimental conditions on model estimation uncertainty. The present study investigated the effects of key experimental conditions, including the time-dependent effect of the censoring interval length, on the estimation uncertainties of the Weibull parameters through Monte Carlo simulations. The simulation results provided quantified estimation uncertainties of Weibull parameters in various cracking test conditions. Hence, it is expected that the results of this study can offer some insight for experimenters developing a probabilistic crack initiation model by performing experiments.

  6. Reference intervals and discrimination values of the Lanthony desaturated D-15 panel test in young to middle-aged Japanese army officials: the Okubo Color Study Report 1.

    Science.gov (United States)

    Shoji, T; Sakurai, Y; Chihara, E; Nishikawa, S; Omae, K

    2009-06-01

    To better understand the reference values and adequate discrimination values of colour vision function with described quantitative systems for the Lanthony desaturated D-15 panel (D-15DS). A total of 1042 Japanese male officials were interviewed and underwent testing using Ishihara pseudoisochromatic plates, standard pseudoisochromatic plates part 2, and the D-15DS. The Farnsworth-Munsell (F-M) 100-hue test and the criteria of Verriest et al were used as definitive tests. Outcomes of the D-15DS were calculated using Bowman's Colour Confusion Index (CCI). The study design included two criteria. In criterion A, subjects with current or past ocular disease and a best-corrected visual acuity less than 0.7 on a decimal visual acuity chart were excluded. In criterion B, among subjects who satisfied criterion A, those who had a congenital colour sense anomaly were excluded. Overall, the 90th percentile (95th percentile) CCI values for criteria A and B in the worse eye were 1.70 (1.95) and 1.59 (1.73), respectively. In subjects satisfying criterion B, the area under the receiver operating characteristic curve was 0.951 (95% confidence interval, 0.931-0.971). The CCI discrimination values of 1.52 or 1.63 showed 90.3% sensitivity and 90% specificity, or 71.5% sensitivity and 95% specificity, respectively, for discriminating acquired colour vision impairment (ACVI). We provided the 90th and 95th percentiles in a young to middle-aged healthy population. The CCI is in good agreement with the diagnosis of ACVI. Our results could be helpful for using D-15DS for screening purposes.

  7. Confidant Relations in Italy

    Directory of Open Access Journals (Sweden)

    Jenny Isaacs

    2015-02-01

    Full Text Available Confidants are often described as the individuals with whom we choose to disclose personal, intimate matters. The presence of a confidant is associated with both mental and physical health benefits. In this study, 135 Italian adults responded to a structured questionnaire that asked if they had a confidant, and if so, to describe various features of the relationship. The vast majority of participants (91% reported the presence of a confidant and regarded this relationship as personally important, high in mutuality and trust, and involving minimal lying. Confidants were significantly more likely to be of the opposite sex. Participants overall were significantly more likely to choose a spouse or other family member as their confidant, rather than someone outside of the family network. Familial confidants were generally seen as closer, and of greater value, than non-familial confidants. These findings are discussed within the context of Italian culture.

  8. First definition of reference intervals of liver function tests in China: a large-population-based multi-center study about healthy adults.

    Science.gov (United States)

    Mu, Runqing; Chen, Wenxiang; Pan, Baishen; Wang, Lanlan; Hao, Xiaoke; Huang, Xianzhang; Qiao, Rui; Zhao, Min; Zhang, Chuanbao; Guo, Wei; Huang, Hengjian; Ma, Yueyun; Zhuang, Junhua; Zhang, Jie; Shang, Hong

    2013-01-01

    Reference intervals of Liver function tests are very important for the screening, diagnosis, treatment, and monitoring of liver diseases. We aim to establish common reference intervals of liver function tests specifically for the Chinese adult population. A total of 3210 individuals (20-79 years) were enrolled in six representative geographical regions in China. Analytes of ALT, AST, GGT, ALP, total protein, albumin and total bilirubin were measured using three analytical systems mainly used in China. The newly established reference intervals were based on the results of traceability or multiple systems, and then validated in 21 large hospitals located nationwide qualified by the National External Quality Assessment (EQA) of China. We had been established reference intervals of the seven liver function tests for the Chinese adult population and found there were apparent variances of reference values for the variables for partitioning analysis such as gender(ALT, GGT, total bilirubin), age(ALP, albumin) and region(total protein). More than 86% of the 21 laboratories passed the validation in all subgroup of reference intervals and overall about 95.3% to 98.8% of the 1220 validation results fell within the range of the new reference interval for all liver function tests. In comparison with the currently recommended reference intervals in China, the single side observed proportions of out of range of reference values from our study for most of the tests deviated significantly from the nominal 2.5% such as total bilirubin (15.2%), ALP (0.2%), albumin (0.0%). Most of reference intervals in our study were obviously different from that of other races. These used reference intervals are no longer applicable for the current Chinese population. We have established common reference intervals of liver function tests that are defined specifically for Chinese population and can be universally used among EQA-approved laboratories located all over China.

  9. Globalization of consumer confidence

    Directory of Open Access Journals (Sweden)

    Çelik Sadullah

    2017-01-01

    Full Text Available The globalization of world economies and the importance of nowcasting analysis have been at the core of the recent literature. Nevertheless, these two strands of research are hardly coupled. This study aims to fill this gap through examining the globalization of the consumer confidence index (CCI by applying conventional and unconventional econometric methods. The US CCI is used as the benchmark in tests of comovement among the CCIs of several developing and developed countries, with the data sets divided into three sub-periods: global liquidity abundance, the Great Recession, and postcrisis. The existence and/or degree of globalization of the CCIs vary according to the period, whereas globalization in the form of coherence and similar paths is observed only during the Great Recession and, surprisingly, stronger in developing/emerging countries.

  10. Multidimensional confidence regions for pareto, exponential, and normal distributions

    OpenAIRE

    Lennartz, Jens

    2017-01-01

    The two classical approaches in estimation theory are point estimation and confidence interval estimation. A confidence interval contains the unknown parameter of interest of a parametric family of distributions with a probability greater than or equal to a certain value, called confidence coefficient or confidence level. If we deal with multiparametric families of distributions, we are interested in simultaneously estimating the parameter vector by determining a multidimensional confidence r...

  11. Statistical intervals a guide for practitioners

    CERN Document Server

    Hahn, Gerald J

    2011-01-01

    Presents a detailed exposition of statistical intervals and emphasizes applications in industry. The discussion differentiates at an elementary level among different kinds of statistical intervals and gives instruction with numerous examples and simple math on how to construct such intervals from sample data. This includes confidence intervals to contain a population percentile, confidence intervals on probability of meeting specified threshold value, and prediction intervals to include observation in a future sample. Also has an appendix containing computer subroutines for nonparametric stati

  12. An approximate confidence interval for recombination fraction in ...

    African Journals Online (AJOL)

    user

    2011-02-14

    Feb 14, 2011 ... Sheehan et al. (1993), Jandaghi (1994) and Abraham et al. (2007). One of the important parameters of interest in genetic linkage analysis is recombination fraction which plays an important role in analysis of pedigree data. In this paper, we proposed a two stage Monte Carlo Gibbs sampling procedure for ...

  13. Bootstrap confidence intervals for three-way component methods

    NARCIS (Netherlands)

    Kiers, H.A.L.; Weigh, C.; Gaul, W.

    2005-01-01

    The two most common component methods for the analysis of three-way data, CANDECOMP/PARAFAC (CP) and Tucker3 analysis, are used to summarize a three-mode three-way data set by means of a number of component matrices, and, in case of Tucker3, a core array, Until recently, no procedures for computing

  14. Confidence Intervals for Omega Coefficient: Proposal for Calculus.

    Science.gov (United States)

    Ventura-León, José Luis

    2018-01-01

    La confiabilidad es entendida como una propiedad métrica de las puntuaciones de un instrumento de medida. Recientemente se viene utilizando el coeficiente omega (ω) para la estimación de la confiabilidad. No obstante, la medición nunca es exacta por la influencia del error aleatorio, por esa razón es necesario calcular y reportar el intervalo de confianza (IC) que permite encontrar en valor verdadero en un rango de medida. En ese contexto, el artículo plantea una forma de estimar el IC mediante el método de bootstrap para facilitar este procedimiento se brindan códigos de R (un software de acceso libre) para que puedan realizarse los cálculos de una forma amigable. Se espera que el artículo sirva de ayuda a los investigadores de ámbito de salud.

  15. Large Sample Confidence Intervals for Item Response Theory Reliability Coefficients

    Science.gov (United States)

    Andersson, Björn; Xin, Tao

    2018-01-01

    In applications of item response theory (IRT), an estimate of the reliability of the ability estimates or sum scores is often reported. However, analytical expressions for the standard errors of the estimators of the reliability coefficients are not available in the literature and therefore the variability associated with the estimated reliability…

  16. Intervals of confidence: Uncertain accounts of global hunger

    NARCIS (Netherlands)

    Yates-Doerr, E.

    2015-01-01

    Global health policy experts tend to organize hunger through scales of ‘the individual’, ‘the community’ and ‘the global’. This organization configures hunger as a discrete, measurable object to be scaled up or down with mathematical certainty. This article offers a counter to this approach, using

  17. Long-Term Maintenance of Immediate or Delayed Extinction Is Determined by the Extinction-Test Interval

    Science.gov (United States)

    Johnson, Justin S.; Escobar, Martha; Kimble, Whitney L.

    2010-01-01

    Short acquisition-extinction intervals (immediate extinction) can lead to either more or less spontaneous recovery than long acquisition-extinction intervals (delayed extinction). Using rat subjects, we observed less spontaneous recovery following immediate than delayed extinction (Experiment 1). However, this was the case only if a relatively…

  18. Interval Training

    Science.gov (United States)

    ... Weston M, et al. Effects of low-volume high-intensity interval training (HIT) on fitness in adults: A meta-analysis ... 2014;44:1005. Gillen JB, et al. Is high-intensity interval training a time-efficient exercise strategy to improve health ...

  19. The discriminative power of the Interval Shuttle Run Test and the Maximal Multistage Shuttle Run Test for playing level of soccer.

    Science.gov (United States)

    Lemmink, K A P M; Verheijen, R; Visscher, C

    2004-09-01

    The purpose of this study was to examine the discriminative power of the recently developed Interval Shuttle Run Test (ISRT) and the widely used Maximal Multistage 20 m Shuttle Run Test (MMSRT) for soccer players at different levels of competition. The main difference between the tests is that the exercise mode of the ISRT is not continuous but intermittent. Instead of 60 s of running per stage in the MMSRT, 30 s of running are alternated with 15 s of walking, twice per stage. Comparative study: within a 2-week period, 81 male soccer players at the Dutch premier league professional, premier league and 3rd division amateur levels performed the ISRT and the MMSRT. The total number of runs was scored for both tests. Only the ISRT distinguished between levels of competition. In general, the ISRT correlated moderately with the MMSRT for players of different levels of competition (rP: 0.52-0.83). In contrast to the MMSRT, the ISRT shows discriminative power for soccer players at different levels of competition supporting the validity of the ISRT for measuring endurance in a more soccer-specific way. As a result of the intermittent character of the ISRT the energetics of the ISRT and the MMSRT are not closely related.

  20. Confidence in Numerical Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hemez, Francois M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-23

    This PowerPoint presentation offers a high-level discussion of uncertainty, confidence and credibility in scientific Modeling and Simulation (M&S). It begins by briefly evoking M&S trends in computational physics and engineering. The first thrust of the discussion is to emphasize that the role of M&S in decision-making is either to support reasoning by similarity or to “forecast,” that is, make predictions about the future or extrapolate to settings or environments that cannot be tested experimentally. The second thrust is to explain that M&S-aided decision-making is an exercise in uncertainty management. The three broad classes of uncertainty in computational physics and engineering are variability and randomness, numerical uncertainty and model-form uncertainty. The last part of the discussion addresses how scientists “think.” This thought process parallels the scientific method where by a hypothesis is formulated, often accompanied by simplifying assumptions, then, physical experiments and numerical simulations are performed to confirm or reject the hypothesis. “Confidence” derives, not just from the levels of training and experience of analysts, but also from the rigor with which these assessments are performed, documented and peer-reviewed.

  1. Unexplained Graft Dysfunction after Heart Transplantation—Role of Novel Molecular Expression Test Score and QTc-Interval: A Case Report

    Directory of Open Access Journals (Sweden)

    Khurram Shahzad

    2010-01-01

    Full Text Available In the current era of immunosuppressive medications there is increased observed incidence of graft dysfunction in the absence of known histological criteria of rejection after heart transplantation. A noninvasive molecular expression diagnostic test was developed and validated to rule out histological acute cellular rejection. In this paper we present for the first time, longitudinal pattern of changes in this novel diagnostic test score along with QTc-interval in a patient who was admitted with unexplained graft dysfunction. Patient presented with graft failure with negative findings on all known criteria of rejection including acute cellular rejection, antibody mediated rejection and cardiac allograft vasculopathy. The molecular expression test score showed gradual increase and QTc-interval showed gradual prolongation with the gradual decline in graft function. This paper exemplifies that in patients presenting with unexplained graft dysfunction, GEP test score and QTc-interval correlate with the changes in the graft function.

  2. Notes on testing equality and interval estimation in Poisson frequency data under a three-treatment three-period crossover trial.

    Science.gov (United States)

    Lui, Kung-Jong; Chang, Kuang-Chao

    2016-10-01

    When the frequency of event occurrences follows a Poisson distribution, we develop procedures for testing equality of treatments and interval estimators for the ratio of mean frequencies between treatments under a three-treatment three-period crossover design. Using Monte Carlo simulations, we evaluate the performance of these test procedures and interval estimators in various situations. We note that all test procedures developed here can perform well with respect to Type I error even when the number of patients per group is moderate. We further note that the two weighted-least-squares (WLS) test procedures derived here are generally preferable to the other two commonly used test procedures in the contingency table analysis. We also demonstrate that both interval estimators based on the WLS method and interval estimators based on Mantel-Haenszel (MH) approach can perform well, and are essentially of equal precision with respect to the average length. We use a double-blind randomized three-treatment three-period crossover trial comparing salbutamol and salmeterol with a placebo with respect to the number of exacerbations of asthma to illustrate the use of these test procedures and estimators. © The Author(s) 2014.

  3. Weighted regression analysis and interval estimators

    Science.gov (United States)

    Donald W. Seegrist

    1974-01-01

    A method for deriving the weighted least squares estimators for the parameters of a multiple regression model. Confidence intervals for expected values, and prediction intervals for the means of future samples are given.

  4. The Confidence Trick

    Directory of Open Access Journals (Sweden)

    Steve Keen

    2009-03-01

    Full Text Available This article reflects on the role that confidence plays in recovery from a financial crisis.The author reflects on lessons from the past – specifically The Great Crash of 1929 and on thework of economists Keynes and Fisher to apply to our current economic woes.The role of overconfidence in our current crisis is also examined.

  5. Adding Confidence to Knowledge

    Science.gov (United States)

    Goodson, Ludwika Aniela; Slater, Don; Zubovic, Yvonne

    2015-01-01

    A "knowledge survey" and a formative evaluation process led to major changes in an instructor's course and teaching methods over a 5-year period. Design of the survey incorporated several innovations, including: a) using "confidence survey" rather than "knowledge survey" as the title; b) completing an instructional…

  6. Confidence of Today's Youth

    Science.gov (United States)

    Intellect, 1977

    1977-01-01

    Results of a survey by the Gallup Organization, Inc., commissioned by the Miami Valley (Ohio) Young Adult Ministry and released at Wright State University, show that young Americans essentially have confidence in the basic American ideas and institutions, such as organized religion, the future of the U.S., free enterprise, labor unions, business…

  7. Short-interval test-retest interrater reliability of the Dutch version of the structured clinical interview for DSM-IV personality disorders (SCID-II)

    NARCIS (Netherlands)

    Weertman, A; ArntZ, A; Dreessen, L; van Velzen, C; Vertommen, S

    2003-01-01

    This study examined the short-interval test-retest reliability of the Structured Clinical Interview (SCID-II: First, Spitzer, Gibbon, & Williams, 1995) for DSM-IV personality disorders (PDs). The SCID-II was administered to 69 in- and outpatients on two occasions separated by 1 to 6 weeks. The

  8. Testing equality and interval estimation in binary responses when high dose cannot be used first under a three-period crossover design.

    Science.gov (United States)

    Lui, Kung-Jong; Chang, Kuang-Chao

    2015-01-01

    When comparing two doses of a new drug with a placebo, we may consider using a crossover design subject to the condition that the high dose cannot be administered before the low dose. Under a random-effects logistic regression model, we focus our attention on dichotomous responses when the high dose cannot be used first under a three-period crossover trial. We derive asymptotic test procedures for testing equality between treatments. We further derive interval estimators to assess the magnitude of the relative treatment effects. We employ Monte Carlo simulation to evaluate the performance of these test procedures and interval estimators in a variety of situations. We use the data taken as a part of trial comparing two different doses of an analgesic with a placebo for the relief of primary dysmenorrhea to illustrate the use of the proposed test procedures and estimators.

  9. Interval estimates and their precision

    Science.gov (United States)

    Marek, Luboš; Vrabec, Michal

    2015-06-01

    A task very often met in in practice is computation of confidence interval bounds for the relative frequency within sampling without replacement. A typical situation includes preelection estimates and similar tasks. In other words, we build the confidence interval for the parameter value M in the parent population of size N on the basis of a random sample of size n. There are many ways to build this interval. We can use a normal or binomial approximation. More accurate values can be looked up in tables. We consider one more method, based on MS Excel calculations. In our paper we compare these different methods for specific values of M and we discuss when the considered methods are suitable. The aim of the article is not a publication of new theoretical methods. This article aims to show that there is a very simple way how to compute the confidence interval bounds without approximations, without tables and without other software costs.

  10. Normal probability plots with confidence.

    Science.gov (United States)

    Chantarangsi, Wanpen; Liu, Wei; Bretz, Frank; Kiatsupaibul, Seksan; Hayter, Anthony J; Wan, Fang

    2015-01-01

    Normal probability plots are widely used as a statistical tool for assessing whether an observed simple random sample is drawn from a normally distributed population. The users, however, have to judge subjectively, if no objective rule is provided, whether the plotted points fall close to a straight line. In this paper, we focus on how a normal probability plot can be augmented by intervals for all the points so that, if the population distribution is normal, then all the points should fall into the corresponding intervals simultaneously with probability 1-α. These simultaneous 1-α probability intervals provide therefore an objective mean to judge whether the plotted points fall close to the straight line: the plotted points fall close to the straight line if and only if all the points fall into the corresponding intervals. The powers of several normal probability plot based (graphical) tests and the most popular nongraphical Anderson-Darling and Shapiro-Wilk tests are compared by simulation. Based on this comparison, recommendations are given in Section 3 on which graphical tests should be used in what circumstances. An example is provided to illustrate the methods. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The five-times-sit-to-stand-test (FTSST), the short version of the activities-specific balance confidence (ABC) scale, and fear of falling predict step execution time (SET) in older adults.

    Science.gov (United States)

    Goldberg, Allon

    2012-01-01

    Rapid stepping is a common strategy employed by older adults to avoid falls. The relative contributions of dynamic balance, balance confidence and fear of falling to SET, was investigated in older adults. Thirty-three community-dwelling older adults completed tests of SET as well as the FTSST, a test of motor performance associated with dynamic balance. Psychological indicators of balance-related confidence assessed were the ABC 6-item scale (ABC-6) and fear of falling. Mean SET was significantly slower in the fear of falling group than in the no fear of falling group (p<0.001). Correlational analysis indicated that poorer performance on the FTSST and lower balance confidence, were associated with slower time to execute a rapid step. A stepwise multiple regression model including the FTSST, ABC-6 score, and fear of falling as predictor variables, explained 58% of the variance in SET (p<0.001). The FTSST explained the largest proportion of the variance in SET (36%), followed by fear of falling (15%) and ABC-6 score (7%). These data show that the FTSST, ABC-6 score and fear of falling are significant and independent predictors of SET in older adults. Dynamic balance, balance confidence and fear of falling, may play important roles in executing rapid steps in older adults. Motor performance and psychological indicators of balance-related confidence appear to have crucial roles in SET in older adults. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  12. The use of regression analysis in determining reference intervals for low hematocrit and thrombocyte count in multiple electrode aggregometry and platelet function analyzer 100 testing of platelet function.

    Science.gov (United States)

    Kuiper, Gerhardus J A J M; Houben, Rik; Wetzels, Rick J H; Verhezen, Paul W M; Oerle, Rene van; Ten Cate, Hugo; Henskens, Yvonne M C; Lancé, Marcus D

    2017-11-01

    Low platelet counts and hematocrit levels hinder whole blood point-of-care testing of platelet function. Thus far, no reference ranges for MEA (multiple electrode aggregometry) and PFA-100 (platelet function analyzer 100) devices exist for low ranges. Through dilution methods of volunteer whole blood, platelet function at low ranges of platelet count and hematocrit levels was assessed on MEA for four agonists and for PFA-100 in two cartridges. Using (multiple) regression analysis, 95% reference intervals were computed for these low ranges. Low platelet counts affected MEA in a positive correlation (all agonists showed r(2) ≥ 0.75) and PFA-100 in an inverse correlation (closure times were prolonged with lower platelet counts). Lowered hematocrit did not affect MEA testing, except for arachidonic acid activation (ASPI), which showed a weak positive correlation (r(2) = 0.14). Closure time on PFA-100 testing was inversely correlated with hematocrit for both cartridges. Regression analysis revealed different 95% reference intervals in comparison with originally established intervals for both MEA and PFA-100 in low platelet or hematocrit conditions. Multiple regression analysis of ASPI and both tests on the PFA-100 for combined low platelet and hematocrit conditions revealed that only PFA-100 testing should be adjusted for both thrombocytopenia and anemia. 95% reference intervals were calculated using multiple regression analysis. However, coefficients of determination of PFA-100 were poor, and some variance remained unexplained. Thus, in this pilot study using (multiple) regression analysis, we could establish reference intervals of platelet function in anemia and thrombocytopenia conditions on PFA-100 and in thrombocytopenia conditions on MEA.

  13. Building confidence in vaccines.

    Science.gov (United States)

    Smith, Jennifer C; Appleton, Mary; MacDonald, Noni E

    2013-01-01

    Despite significant efforts by governments, organizations and individuals to maintain public trust in vaccines, concerns persist and threaten to undermine the effectiveness of immunization programs. Vaccine advocates have traditionally focused on education based on evidence to address vaccine concerns and hesitancy. However, being informed of the facts about immunization does not always translate into support for immunization. While many are persuaded by scientific evidence, others are more influenced by cognitive shortcuts, beliefs, societal pressure and the media, with the latter group more likely to hesitate over immunization. Understanding evidence from the behaviour sciences opens new doors to better support individual decision-making about immunization. Drawing on heuristics, this overview explores how individuals find, process and utilize vaccine information and the role health care professionals and society can play in vaccine decision-making. Traditional, evidence-based approaches aimed at staunching the erosion of public confidence in vaccines are proving inadequate and expensive. Enhancing public confidence in vaccines will be complex, necessitating a much wider range of strategies than currently used. Success will require a shift in how the public, health care professionals and media are informed and educated about vaccine benefits, risks and safety; considerable introspection and change in current academic and vaccine decision-making practices; development of proactive strategies to broadly address current and potential future concerns, as well as targeted interventions such as programs to address pain with immunization. This overview outlines ten such opportunities for change to improve vaccine confidence.

  14. Confidence-Based Feature Acquisition

    Science.gov (United States)

    Wagstaff, Kiri L.; desJardins, Marie; MacGlashan, James

    2010-01-01

    Confidence-based Feature Acquisition (CFA) is a novel, supervised learning method for acquiring missing feature values when there is missing data at both training (learning) and test (deployment) time. To train a machine learning classifier, data is encoded with a series of input features describing each item. In some applications, the training data may have missing values for some of the features, which can be acquired at a given cost. A relevant JPL example is that of the Mars rover exploration in which the features are obtained from a variety of different instruments, with different power consumption and integration time costs. The challenge is to decide which features will lead to increased classification performance and are therefore worth acquiring (paying the cost). To solve this problem, CFA, which is made up of two algorithms (CFA-train and CFA-predict), has been designed to greedily minimize total acquisition cost (during training and testing) while aiming for a specific accuracy level (specified as a confidence threshold). With this method, it is assumed that there is a nonempty subset of features that are free; that is, every instance in the data set includes these features initially for zero cost. It is also assumed that the feature acquisition (FA) cost associated with each feature is known in advance, and that the FA cost for a given feature is the same for all instances. Finally, CFA requires that the base-level classifiers produce not only a classification, but also a confidence (or posterior probability).

  15. Reclaim your creative confidence.

    Science.gov (United States)

    Kelley, Tom; Kelley, David

    2012-12-01

    Most people are born creative. But over time, a lot of us learn to stifle those impulses. We become warier of judgment, more cautious more analytical. The world seems to divide into "creatives" and "noncreatives," and too many people resign themselves to the latter category. And yet we know that creativity is essential to success in any discipline or industry. The good news, according to authors Tom Kelley and David Kelley of IDEO, is that we all can rediscover our creative confidence. The trick is to overcome the four big fears that hold most of us back: fear of the messy unknown, fear of judgment, fear of the first step, and fear of losing control. The authors use an approach based on the work of psychologist Albert Bandura in helping patients get over their snake phobias: You break challenges down into small steps and then build confidence by succeeding on one after another. Creativity is something you practice, say the authors, not just a talent you are born with.

  16. Effect of continuous and interval exercise training on the PETCO2 response during a graded exercise test in patients with coronary artery disease

    OpenAIRE

    Enéas A. Rocco; Prado, Danilo M L; Silva, Alexandre G.; Lazzari, Jaqueline M. A.; Bortz, Pedro C; Rocco,Débora F. M.; Carla G. Rosa; Valter Furlan

    2012-01-01

    OBJECTIVE: The purpose of this study was to evaluate the following: 1) the effects of continuous exercise training and interval exercise training on the end-tidal carbon dioxide pressure (PETCO2) response during a graded exercise test in patients with coronary artery disease; and 2) the effects of exercise training modalities on the association between PETCO2 at the ventilatory anaerobic threshold (VAT) and indicators of ventilatory efficiency and cardiorespiratory fitness in patients with co...

  17. The longitudinal association of marital confidence, time spent together, and marital satisfaction.

    Science.gov (United States)

    Johnson, Matthew D; Anderson, Jared R

    2013-06-01

    Using three waves of dyadic data collected at 18-month intervals from a community-based sample of 610 newly married heterosexual couples (1 220 individuals), we examined the relationship between marital confidence, time spent together, and marital satisfaction using a modified actor-partner interdependence model. Results indicate that after controlling for marital satisfaction and time spent together at Time 1, marital confidence around the time of marriage was associated with marital satisfaction approximately 3 years later. In addition, marital confidence was associated with how much time husbands and wives spent together at Time 2, which was related to marital satisfaction at Time 3. Tests of the mediating paths from marital confidence to marital satisfaction trended toward significance. The results suggest the importance of assessing for relationship confidence when working with couples in the early stages of their relationship. © FPI, Inc.

  18. Confidence sets for optimal factor levels of a response surface.

    Science.gov (United States)

    Wan, Fang; Liu, Wei; Bretz, Frank; Han, Yang

    2016-12-01

    Construction of confidence sets for the optimal factor levels is an important topic in response surfaces methodology. In Wan et al. (2015), an exact (1-α) confidence set has been provided for a maximum or minimum point (i.e., an optimal factor level) of a univariate polynomial function in a given interval. In this article, the method has been extended to construct an exact (1-α) confidence set for the optimal factor levels of response surfaces. The construction method is readily applied to many parametric and semiparametric regression models involving a quadratic function. A conservative confidence set has been provided as an intermediate step in the construction of the exact confidence set. Two examples are given to illustrate the application of the confidence sets. The comparison between confidence sets indicates that our exact confidence set is better than the only other confidence set available in the statistical literature that guarantees the (1-α) confidence level. © 2016, The International Biometric Society.

  19. Self-Confidence and Metacognitive Processes

    Science.gov (United States)

    Kleitman, Sabina; Stankov, Lazar

    2007-01-01

    This paper examines the nature of the Self-confidence factor. In particular, we study the relationship between this factor and cognitive, metacognitive, and personality measures. Participants (N=296) were administered a battery of seven cognitive tests that assess three constructs: accuracy, speed, and confidence. Participants were also given the…

  20. The effect of an enrolled nursing registration pathway program on undergraduate nursing students' confidence level: A pre- and post-test study.

    Science.gov (United States)

    Crevacore, Carol; Jonas-Dwyer, Diana; Nicol, Pam

    2016-04-01

    In the latter half of the 20th century, registered nurse education moved to university degree level. As a result, there has been a reduction in access for students to clinical experience. In numerous studies, nursing graduates have reported that they do not feel prepared for practice. The importance of maximising every learning opportunity during nursing school is paramount. At Edith Cowan University, a program was initiated that allows students to become enrolled nurses at the midway point of their degree to enable them to work and therefore gain experience in the clinical practice setting during their education. This study investigated the effect of the program on the nursing students' perception of their clinical abilities and explored their ability to link theory to practice. The research design for this study was a quasi-experimental, prospective observational cohort study. The study included 39 second-year nursing students not enrolled in the program (Group 1), 45 second-year nursing students enrolled in the program (Group 2), and 28 third-year nursing students who completed the program and are working as enrolled nurses (Group 3). Participants were asked to complete a Five Dimension of Nursing Scale questionnaire. The quantitative analyses showed that students in Group 1 had statistically significant higher pre-questionnaire perceived abilities across all domains, except in two dimensions when compared to Group 2. The post-questionnaire analysis showed that Group 1 had statistically significant lower perceived abilities in four of the five dimensions compared to Group 2. Group 1 also had significantly lower abilities in all dimensions compared to Group 3. Group 3 had a significantly higher perception of their clinical abilities compared to Group 2. This study highlights the value of meaningful employment for undergraduate nursing students by providing opportunities to increase confidence in clinical abilities. Copyright © 2016 Elsevier Ltd. All rights

  1. Psychometric testing on the NLN Student Satisfaction and Self-Confidence in Learning, Simulation Design Scale, and Educational Practices Questionnaire using a sample of pre-licensure novice nurses.

    Science.gov (United States)

    Franklin, Ashley E; Burns, Paulette; Lee, Christopher S

    2014-10-01

    In 2006, the National League for Nursing published three measures related to novice nurses' beliefs about self-confidence, scenario design, and educational practices associated with simulation. Despite the extensive use of these measures, little is known about their reliability and validity. The psychometric properties of the Student Satisfaction and Self-Confidence in Learning Scale, Simulation Design Scale, and Educational Practices Questionnaire were studied among a sample of 2200 surveys completed by novice nurses from a liberal arts university in the southern United States. Psychometric tests included item analysis, confirmatory and exploratory factor analyses in randomly-split subsamples, concordant and discordant validity, and internal consistency. All three measures have sufficient reliability and validity to be used in education research. There is room for improvement in content validity with the Student Satisfaction and Self-Confidence in Learning and Simulation Design Scale. This work provides robust evidence to ensure that judgments made about self-confidence after simulation, simulation design and educational practices are valid and reliable. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. We will be champions: Leaders' confidence in 'us' inspires team members' team confidence and performance.

    Science.gov (United States)

    Fransen, K; Steffens, N K; Haslam, S A; Vanbeselaere, N; Vande Broek, G; Boen, F

    2016-12-01

    The present research examines the impact of leaders' confidence in their team on the team confidence and performance of their teammates. In an experiment involving newly assembled soccer teams, we manipulated the team confidence expressed by the team leader (high vs neutral vs low) and assessed team members' responses and performance as they unfolded during a competition (i.e., in a first baseline session and a second test session). Our findings pointed to team confidence contagion such that when the leader had expressed high (rather than neutral or low) team confidence, team members perceived their team to be more efficacious and were more confident in the team's ability to win. Moreover, leaders' team confidence affected individual and team performance such that teams led by a highly confident leader performed better than those led by a less confident leader. Finally, the results supported a hypothesized mediational model in showing that the effect of leaders' confidence on team members' team confidence and performance was mediated by the leader's perceived identity leadership and members' team identification. In conclusion, the findings of this experiment suggest that leaders' team confidence can enhance members' team confidence and performance by fostering members' identification with the team. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Exploring the Relationships among Teacher Confidence, Learning, and Test Performance within the English-for-Teaching Course. Research Report. ETS RR-16-24

    Science.gov (United States)

    Gu, Lin; Papageorgiou, Spiros

    2016-01-01

    In responding to the increasingly expanded emphasis on English language teaching (ELT) around the globe, Educational Testing Service (ETS) collaborated with National Geographic Learning to develop the "ELTeach"™ program (http://www.elteach.com), an online professional development program consisting of two courses, English-for-Teaching…

  4. Self-confidence and metacognitive processes

    Directory of Open Access Journals (Sweden)

    Kleitman Sabina

    2005-01-01

    Full Text Available This paper examines the status of Self-confidence trait. Two studies strongly suggest that Self-confidence is a component of metacognition. In the first study, participants (N=132 were administered measures of Self-concept, a newly devised Memory and Reasoning Competence Inventory (MARCI, and a Verbal Reasoning Test (VRT. The results indicate a significant relationship between confidence ratings on the VRT and the Reasoning component of MARCI. The second study (N=296 employed an extensive battery of cognitive tests and several metacognitive measures. Results indicate the presence of robust Self-confidence and Metacognitive Awareness factors, and a significant correlation between them. Self-confidence taps not only processes linked to performance on items that have correct answers, but also beliefs about events that may never occur.

  5. Monitoring tigers with confidence.

    Science.gov (United States)

    Linkie, Matthew; Guillera-Arroita, Gurutzeta; Smith, Joseph; Rayan, D Mark

    2010-12-01

    With only 5% of the world's wild tigers (Panthera tigris Linnaeus, 1758) remaining since the last century, conservationists urgently need to know whether or not the management strategies currently being employed are effectively protecting these tigers. This knowledge is contingent on the ability to reliably monitor tiger populations, or subsets, over space and time. In the this paper, we focus on the 2 seminal methodologies (camera trap and occupancy surveys) that have enabled the monitoring of tiger populations with greater confidence. Specifically, we: (i) describe their statistical theory and application in the field; (ii) discuss issues associated with their survey designs and state variable modeling; and, (iii) discuss their future directions. These methods have had an unprecedented influence on increasing statistical rigor within tiger surveys and, also, surveys of other carnivore species. Nevertheless, only 2 published camera trap studies have gone beyond single baseline assessments and actually monitored population trends. For low density tiger populations (e.g. tiger/100 km(2)) obtaining sufficient precision for state variable estimates from camera trapping remains a challenge because of insufficient detection probabilities and/or sample sizes. Occupancy surveys have overcome this problem by redefining the sampling unit (e.g. grid cells and not individual tigers). Current research is focusing on developing spatially explicit capture-mark-recapture models and estimating abundance indices from landscape-scale occupancy surveys, as well as the use of genetic information for identifying and monitoring tigers. The widespread application of these monitoring methods in the field now enables complementary studies on the impact of the different threats to tiger populations and their response to varying management intervention. © 2010 ISZS, Blackwell Publishing and IOZ/CAS.

  6. Recognition memory across the lifespan: The impact of word frequency and study-test interval on estimates of familiarity and recollection

    Directory of Open Access Journals (Sweden)

    Beat eMeier

    2013-10-01

    Full Text Available The goal of this study was to investigate recognition memory performance across the lifespan and to determine how estimates of recollection and familiarity contribute to performance. In each of three experiments, participants from five groups from 14 up to 85 years of age (children, young adults, middle-aged adults, young-old adults and old-old adults were presented with high- and low-frequency words in a study phase and were tested immediately afterwards and/or after a one day retention interval. The results showed that word frequency and retention interval affected recognition memory performance as well as estimates of recollection and familiarity. Across the lifespan, the trajectory of recognition memory followed an inverse u-shape function that was neither affected by word frequency nor by retention interval. The trajectory of estimates of recollection also followed an inverse u-shape function, and was especially pronounced for low-frequency words. In contrast, estimates of familiarity did not differ across the lifespan. The results indicate that age differences in recognition memory are mainly due to differences in processes related to recollection while the contribution of familiarity-based processes seems to be age-invariant.

  7. Improving the performance of the Egyptian second testing nuclear research reactor using interval type-2 fuzzy logic controller tuned by modified biogeography-based optimization

    Energy Technology Data Exchange (ETDEWEB)

    Sayed, M.M., E-mail: M.M.Sayed@ieee.org; Saad, M.S.; Emara, H.M.; Abou El-Zahab, E.E.

    2013-09-15

    Highlights: • A modified version of the BBO was proposed. • A novel method for interval type-2 FLC design tuned by MBBO was proposed. • The performance of the ETRR-2 was improved by using IT2FLC tuned by MBBO. -- Abstract: Power stabilization is a critical issue in nuclear reactors. The conventional proportional derivative (PD) controller is currently used in the Egyptian second testing research reactor (ETRR-2). In this paper, we propose a modified biogeography-based optimization (MBBO) algorithm to design the interval type-2 fuzzy logic controller (IT2FLC) to improve the performance of the Egyptian second testing research reactor (ETRR-2). Biogeography-based optimization (BBO) is a novel evolutionary algorithm that is based on the mathematical models of biogeography. Biogeography is the study of the geographical distribution of biological organisms. In the BBO model, problem solutions are represented as islands, and the sharing of features between solutions is represented as immigration and emigration between the islands. A modified version of the BBO is applied to design the IT2FLC to get the optimal parameters of the membership functions of the controller. We test the optimal IT2FLC obtained by modified biogeography-based optimization (MBBO) using the integral square error (ISE) and is compared with the currently used PD controller.

  8. Development and interval testing of a naturalistic driving methodology to evaluate driving behavior in clinical research [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Ganesh M. Babulal

    2016-09-01

    Full Text Available Background: The number of older adults in the United States will double by 2056. Additionally, the number of licensed drivers will increase along with extended driving-life expectancy. Motor vehicle crashes are a leading cause of injury and death in older adults. Alzheimer’s disease (AD also negatively impacts driving ability and increases crash risk. Conventional methods to evaluate driving ability are limited in predicting decline among older adults. Innovations in GPS hardware and software can monitor driving behavior in the actual environments people drive in. Commercial off-the-shelf (COTS devices are affordable, easy to install and capture large volumes of data in real-time. However, adapting these methodologies for research can be challenging. This study sought to adapt a COTS device and determine an interval that produced accurate data on the actual route driven for use in future studies involving older adults with and without AD.  Methods: Three subjects drove a single course in different vehicles at different intervals (30, 60 and 120 seconds, at different times of day, morning (9:00-11:59AM, afternoon (2:00-5:00PM and night (7:00-10pm. The nine datasets were examined to determine the optimal collection interval. Results: Compared to the 120-second and 60-second intervals, the 30-second interval was optimal in capturing the actual route driven along with the lowest number of incorrect paths and affordability weighing considerations for data storage and curation. Discussion: Use of COTS devices offers minimal installation efforts, unobtrusive monitoring and discreet data extraction.  However, these devices require strict protocols and controlled testing for adoption into research paradigms.  After reliability and validity testing, these devices may provide valuable insight into daily driving behaviors and intraindividual change over time for populations of older adults with and without AD.  Data can be aggregated over time to look

  9. The determination of critical rest interval from the intermittent critical velocity test in club-level collegiate hockey and rugby players.

    Science.gov (United States)

    Fukuda, David H; Smith, Abbie E; Kendall, Kristina L; Cramer, Joel T; Stout, Jeffrey R

    2011-04-01

    The intermittent critical velocity (ICV) test is used to quantify the relationship between velocity and time to exhaustion, yielding an aerobic parameter (ICV), an anaerobic parameter (anaerobic running capacity [ARC]), and critical rest interval (CRI). Critical rest interval is the theoretical rest period needed to maintain repeated bouts of exercise for an extended period of time without inducing fatigue during intermittent treadmill running. Fourteen collegiate, club-level male participants (mean ± SD; age: 21.4 ± 1.8 years; weight: 82.8 ± 5.9 kg; body fat: 11.8 ± 5.4%; and VO2max: 51.2 ± 2.8 ml · kg · min), primarily hockey and rugby players, completed the ICV test, using 15-second repeated sprints to exhaustion during separate sessions of treadmill running at varying supramaximal intensities. The time and total distance for each running session were used to determine ICV and ARC via linear regression. The CRI was calculated using the relationship between total distance during the ICV test and the number of intervals completed. Mean ICV and ARC (± SD) values were calculated as 4.80 ± 0.3 m · s and 154.1 ± 36 m, respectively. The mean ICV values were significantly different from the mean peak velocity (± SD) (4.67 ± 0.17 m · s) achieved during the VO2max test (p = 0.011). The CRI was calculated as mean ± SD: 33.9 ± 1.9 seconds. Body fat percentage measured by air displacement plethysmography (BOD POD®; r = -0.649; p = 0.012), lean body mass (r = -0.556; p = 0.039), fat mass (r = -0.634; p = 0.015), body weight (r = -0.669; p = 0.006), and relative VO2max (r = 0.562; p = 0.036) were significantly correlated with ICV. The ARC (r = 0.804; p = 0.001) and velocity at ventilatory threshold (r = -0.630; p = 0.016) were significantly correlated with CRI. The ability to quantify CRI, an additional variable derived from the ICV test, provides a possible measure that can be used in the prescription and evaluation of training methods.

  10. Confidence bounds for normal and lognormal distribution coefficients of variation

    Science.gov (United States)

    Steve Verrill

    2003-01-01

    This paper compares the so-called exact approach for obtaining confidence intervals on normal distribution coefficients of variation to approximate methods. Approximate approaches were found to perform less well than the exact approach for large coefficients of variation and small sample sizes. Web-based computer programs are described for calculating confidence...

  11. Challenges and opportunities in implementing the FDA default parametric tolerance interval two one-sided test for delivered dose uniformity of orally inhaled products.

    Science.gov (United States)

    Larner, Greg; Cooper, Andrew; Lyapustina, Svetlana; Leiner, Stefan; Christopher, David; Strickland, Helen; Golden, Michael; Delzeit, Hans-Joachim; Friedman, Emil M

    2011-12-01

    The goal of this article is to discuss considerations regarding implementation of the parametric tolerance interval two one-sided test (PTI-TOST) for delivered dose uniformity (DDU) of orally inhaled products (OIPs). That test was proposed by FDA in 2005 as an alternative to the counting test described in the 1998 draft FDA guidance for metered dose inhalers and dry powder inhalers. The 2005 PTI-TOST, however, still has not found much use in practice despite the general desirability of parametric approaches in modern pharmaceutical quality control. A key reason for its slow uptake is that it rejects, with high probability, batches whose quality is considered acceptable by all other published regulatory and pharmacopeial standards as well as by the DDU specifications for many approved OIPs. Manufacturers therefore continue using nonparametric counting tests for control of DDU. A simulated case study presented here compares the consequences of the PTI-TOST compared to the counting test. The article discusses three possibilities that would help increase the uptake of the PTI-TOST approach, namely: product-specific quality standards, a different default standard suitable for the majority of OIPs, and integration of the PTI-TOST with a continuous verification control strategy rather than using it as an isolated-batch (transactional) end-product testing. In any of these efforts, if a parametric test is used, it is critical not to set the target quality close to, or at the boundary of the process/product capabilities, because PTI tests are designed to reject with high probability the identified target quality.

  12. Highly Confident, but Wrong: Gender Differences and Similarities in Confidence Judgments.

    Science.gov (United States)

    Lundeberg, Mary A.; And Others

    Although gender differences are fairly consistent when men and women report their general confidence, much less is known about the existence of such differences when subjects are asked to assess the degree of confidence they have in their ability to answer any particular test or exam question. The objective of this research was to investigate…

  13. Observed confidence levels theory and application

    CERN Document Server

    Polansky, Alan M

    2007-01-01

    Illustrating a simple, novel method for solving an array of statistical problems, Observed Confidence Levels: Theory and Application describes the basic development of observed confidence levels, a methodology that can be applied to a variety of common multiple testing problems in statistical inference. It focuses on the modern nonparametric framework of bootstrap-based estimates, allowing for substantial theoretical development and for relatively simple solutions to numerous interesting problems. After an introduction, the book develops the theory and application of observed confidence levels for general scalar parameters, vector parameters, and linear models. It then examines nonparametric problems often associated with smoothing methods, including nonparametric density estimation and regression. The author also describes applications in generalized linear models, classical nonparametric statistics, multivariate analysis, and survival analysis as well as compares the method of observed confidence levels to...

  14. An Investigation of Possible Test Floor Effects By Comparing Score Distributions for Students Tested With Two Different Levels of a Test Battery at Four Different Times Over a Two-Year Interval. Iowa Testing Programs Occasional Papers. Number 24.

    Science.gov (United States)

    Olsen, Scott A.

    When a program evaluation is conducted on the basis of gains made in standardized achievement test scores between a pretest and a posttest, serious bias can result where a floor effect exists on one or both of the test levels. Based upon the expanded standard scores on the Comprehensive Tests of Basic Skills from three successive regular spring…

  15. Distinguishing highly confident accurate and inaccurate memory: insights about relevant and irrelevant influences on memory confidence

    Science.gov (United States)

    Chua, Elizabeth F.; Hannula, Deborah E.; Ranganath, Charan

    2012-01-01

    It is generally believed that accuracy and confidence in one’s memory are related, but there are many instances when they diverge. Accordingly, it is important to disentangle the factors which contribute to memory accuracy and confidence, especially those factors that contribute to confidence, but not accuracy. We used eye movements to separately measure fluent cue processing, the target recognition experience, and relative evidence assessment on recognition confidence and accuracy. Eye movements were monitored during a face-scene associative recognition task, in which participants first saw a scene cue, followed by a forced-choice recognition test for the associated face, with confidence ratings. Eye movement indices of the target recognition experience were largely indicative of accuracy, and showed a relationship to confidence for accurate decisions. In contrast, eye movements during the scene cue raised the possibility that more fluent cue processing was related to higher confidence for both accurate and inaccurate recognition decisions. In a second experiment, we manipulated cue familiarity, and therefore cue fluency. Participants showed higher confidence for cue-target associations for when the cue was more familiar, especially for incorrect responses. These results suggest that over-reliance on cue familiarity and under-reliance on the target recognition experience may lead to erroneous confidence. PMID:22171810

  16. The effects of lubricant eye drops on visual function as measured by the Inter-blink interval Visual Acuity Decay test

    Directory of Open Access Journals (Sweden)

    Gail Torkildsen

    2009-09-01

    Full Text Available Gail TorkildsenAndover Eye Associates, Andover, MA, USAObjective: The purpose of the current study was to evaluate the effects of two marketed ocular lubricants on the visual decay in dry eye patients using the Inter-blink interval Visual Acuity Decay (IVAD test.Methods: This controlled, randomized, double-masked crossover study compared the effects of a polyethylene glycol/propylene glycol-based (PEG/PG tear and a carboxymethylcellulose sodium (CMC/glycerin tear on the visual acuity decay between blinks of dry eye patients. At visit 1 (Day 0, baseline IVAD measurements were recorded prior to instillation of a single drop of randomized study medication. IVAD testing was repeated at 15-, 45-, and 90-minutes post-instillation. Reading rate and functional blink rate were also evaluated. At the second visit (Day 7 ± 3, study procedures were repeated using crossover treatment.Results: Forty-eight (48 subjects with dry eye (61.1 ± 14.8 years old, 79.2% female, 95.8% white completed the study. Treatment with the PEG/PG-based tear demonstrated statistically significantly longer time to one-line loss of best-corrected visual acuity (BCVA as determined by the IVAD test at 90 minutes post-instillation compared to the CMC/glycerin tear (P = 0.0365. Measurements of median time at BCVA, reading rate, and functional blink rate were similar for both treatments. Both formulations were well tolerated in the population studied.Conclusions: Treatment with the PEG/PG-based tear demonstrated statistically significant improved maintenance of visual acuity between blinks at 90 minutes post-instillation compared to the CMC/glycerin tear. This is the first study to demonstrate the ability of an artificial tear to extend visual acuity maintenance between blinks, as measured by the IVAD test.Keywords: dry eye, visual function, artificial tears, ocular lubricant

  17. Coverage Probability of Wald Interval for Binomial Parameters

    OpenAIRE

    Chen, Xinjia

    2008-01-01

    In this paper, we develop an exact method for computing the minimum coverage probability of Wald interval for estimation of binomial parameters. Similar approach can be used for other type of confidence intervals.

  18. Assessing Undergraduate Students' Conceptual Understanding and Confidence of Electromagnetics

    Science.gov (United States)

    Leppavirta, Johanna

    2012-01-01

    The study examines how students' conceptual understanding changes from high confidence with incorrect conceptions to high confidence with correct conceptions when reasoning about electromagnetics. The Conceptual Survey of Electricity and Magnetism test is weighted with students' self-rated confidence on each item in order to infer how strongly…

  19. Self-Confidence and Strategic Deterrence

    OpenAIRE

    Charness, Gary; Rustichini, Aldo; van de Ven, Jeroen

    2011-01-01

    We examine factors that may contribute to 'overconfidence' in relative ability on an intelligence test. We test experimentally for evidence of self-esteem concerns and instrumental strategic concerns. Errors in Bayesian updating are rare when the information does not involve own relative ability, but far more common when it does, suggesting self-esteem issues. There is also strong evidence that males state higher levels of confidence in relative ability when this precedes a tournament; as ent...

  20. Asymptotically Honest Confidence Regions for High Dimensional

    DEFF Research Database (Denmark)

    Caner, Mehmet; Kock, Anders Bredahl

    While variable selection and oracle inequalities for the estimation and prediction error have received considerable attention in the literature on high-dimensional models, very little work has been done in the area of testing and construction of confidence bands in high-dimensional models. However...... of the asymptotic covariance matrix of an increasing number of parameters which is robust against conditional heteroskedasticity. To our knowledge we are the first to do so. Next, we show that our confidence bands are honest over sparse high-dimensional sub vectors of the parameter space and that they contract...... at the optimal rate. All our results are valid in high-dimensional models. Our simulations reveal that the desparsified conservative Lasso estimates the parameters much more precisely than the desparsified Lasso, has much better size properties and produces confidence bands with markedly superior coverage rates....

  1. Parents' obesity-related behavior and confidence to support behavioral change in their obese child: data from the STAR study.

    Science.gov (United States)

    Arsenault, Lisa N; Xu, Kathleen; Taveras, Elsie M; Hacker, Karen A

    2014-01-01

    Successful childhood obesity interventions frequently focus on behavioral modification and involve parents or family members. Parental confidence in supporting behavior change may be an element of successful family-based prevention efforts. We aimed to determine whether parents' own obesity-related behaviors were related to their confidence in supporting their child's achievement of obesity-related behavioral goals. Cross-sectional analyses of data collected at baseline of a randomized control trial testing a treatment intervention for obese children (n = 787) in primary care settings (n = 14). Five obesity-related behaviors (physical activity, screen time, sugar-sweetened beverage, sleep duration, fast food) were self-reported by parents for themselves and their child. Behaviors were dichotomized on the basis of achievement of behavioral goals. Five confidence questions asked how confident the parent was in helping their child achieve each goal. Logistic regression modeling high confidence was conducted with goal achievement and demographics as independent variables. Parents achieving physical activity or sleep duration goals were significantly more likely to be highly confident in supporting their child's achievement of those goals (physical activity, odds ratio 1.76; 95% confidence interval 1.19-2.60; sleep, odds ratio 1.74; 95% confidence interval 1.09-2.79) independent of sociodemographic variables and child's current behavior. Parental achievements of TV watching and fast food goals were also associated with confidence, but significance was attenuated after child's behavior was included in models. Parents' own obesity-related behaviors are factors that may affect their confidence to support their child's behavior change. Providers seeking to prevent childhood obesity should address parent/family behaviors as part of their obesity prevention strategies. Copyright © 2014 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  2. Professional confidence: a concept analysis.

    Science.gov (United States)

    Holland, Kathlyn; Middleton, Lyn; Uys, Leana

    2012-03-01

    Professional confidence is a concept that is frequently used and or implied in occupational therapy literature, but often without specifying its meaning. Rodgers's Model of Concept Analysis was used to analyse the term "professional confidence". Published research obtained from a federated search in four health sciences databases was used to inform the concept analysis. The definitions, attributes, antecedents, and consequences of professional confidence as evidenced in the literature are discussed. Surrogate terms and related concepts are identified, and a model case of the concept provided. Based on the analysis, professional confidence can be described as a dynamic, maturing personal belief held by a professional or student. This includes an understanding of and a belief in the role, scope of practice, and significance of the profession, and is based on their capacity to competently fulfil these expectations, fostered through a process of affirming experiences. Developing and fostering professional confidence should be nurtured and valued to the same extent as professional competence, as the former underpins the latter, and both are linked to professional identity.

  3. Confidence-Based Learning in Investment Analysis

    Science.gov (United States)

    Serradell-Lopez, Enric; Lara-Navarra, Pablo; Castillo-Merino, David; González-González, Inés

    The aim of this study is to determine the effectiveness of using multiple choice tests in subjects related to the administration and business management. To this end we used a multiple-choice test with specific questions to verify the extent of knowledge gained and the confidence and trust in the answers. The tests were performed in a group of 200 students at the bachelor's degree in Business Administration and Management. The analysis made have been implemented in one subject of the scope of investment analysis and measured the level of knowledge gained and the degree of trust and security in the responses at two different times of the course. The measurements have been taken into account different levels of difficulty in the questions asked and the time spent by students to complete the test. The results confirm that students are generally able to obtain more knowledge along the way and get increases in the degree of trust and confidence in the answers. It is confirmed as the difficulty level of the questions set a priori by the heads of the subjects are related to levels of security and confidence in the answers. It is estimated that the improvement in the skills learned is viewed favourably by businesses and are especially important for job placement of students.

  4. Contraceptive confidence and timing of first birth in Moldova: an event history analysis of retrospective data.

    Science.gov (United States)

    Lyons-Amos, Mark; Padmadas, Sabu S; Durrant, Gabriele B

    2014-08-11

    To test the contraceptive confidence hypothesis in a modern context. The hypothesis is that women using effective or modern contraceptive methods have increased contraceptive confidence and hence a shorter interval between marriage and first birth than users of ineffective or traditional methods. We extend the hypothesis to incorporate the role of abortion, arguing that it acts as a substitute for contraception in the study context. Moldova, a country in South-East Europe. Moldova exhibits high use of traditional contraceptive methods and abortion compared with other European countries. Data are from a secondary analysis of the 2005 Moldovan Demographic and Health Survey, a nationally representative sample survey. 5377 unmarried women were selected. The outcome measure was the interval between marriage and first birth. This was modelled using a piecewise-constant hazard regression, with abortion and contraceptive method types as primary variables along with relevant sociodemographic controls. Women with high contraceptive confidence (modern method users) have a higher cumulative hazard of first birth 36 months following marriage (0.88 (0.87 to 0.89)) compared with women with low contraceptive confidence (traditional method users, cumulative hazard: 0.85 (0.84 to 0.85)). This is consistent with the contraceptive confidence hypothesis. There is a higher cumulative hazard of first birth among women with low (0.80 (0.79 to 0.80)) and moderate abortion propensities (0.76 (0.75 to 0.77)) than women with no abortion propensity (0.73 (0.72 to 0.74)) 24 months after marriage. Effective contraceptive use tends to increase contraceptive confidence and is associated with a shorter interval between marriage and first birth. Increased use of abortion also tends to increase contraceptive confidence and shorten birth duration, although this effect is non-linear-women with a very high use of abortion tend to have lengthy intervals between marriage and first birth. Published by

  5. Alan Greenspan, the confidence strategy

    Directory of Open Access Journals (Sweden)

    Edwin Le Heron

    2006-12-01

    Full Text Available To evaluate the Greenspan era, we nevertheless need to address three questions: Is his success due to talent or just luck? Does he have a system of monetary policy or is he himself the system? What will be his legacy? Greenspan was certainly lucky, but he was also clairvoyant. Above all, he has developed a profoundly original monetary policy. His confidence strategy is clearly opposed to the credibility strategy developed in central banks and the academic milieu after 1980, but also inflation targeting, which today constitutes the mainstream monetary policy regime. The question of his legacy seems more nuanced. However, Greenspan will remain 'for a considerable period of time' a highly heterodox and original central banker. His political vision, his perception of an uncertain world, his pragmatism and his openness form the structure of a powerful alternative system, the confidence strategy, which will leave its mark on the history of monetary policy.

  6. Confidence scores for prediction models

    DEFF Research Database (Denmark)

    Gerds, Thomas Alexander; van de Wiel, MA

    2011-01-01

    modelling strategy is applied to different training sets. For each modelling strategy we estimate a confidence score based on the same repeated bootstraps. A new decomposition of the expected Brier score is obtained, as well as the estimates of population average confidence scores. The latter can be used......In medical statistics, many alternative strategies are available for building a prediction model based on training data. Prediction models are routinely compared by means of their prediction performance in independent validation data. If only one data set is available for training and validation......, then rival strategies can still be compared based on repeated bootstraps of the same data. Often, however, the overall performance of rival strategies is similar and it is thus difficult to decide for one model. Here, we investigate the variability of the prediction models that results when the same...

  7. Steady, dynamic and structural deformation (three interval thixotropy test) characteristics of gluten-free Tarhana soup prepared with different concentrations of quinoa flour.

    Science.gov (United States)

    Demir, M Kürşat; Kutlu, Gözde; Yilmaz, Mustafa T

    2017-04-01

    Celiac disease is among the most important health problems and the most important feature of this disease is its being the only lifelong food allergy. To overcome this problem, some gluten-free and starch based food products have been generally introduced to the market; however, these products are starch based with low nutritive value. Therefore, it is important to enrich such products for individuals who are obliged to be nourished by gluten-free diet. In this study, wheat flour was replaced with quinoa flour (QF) in the production of tarhana. The objective of this work was to investigate the steady shear, viscoelastic and deformation and recovery properties (applying three interval thixotropy test (3ITT)) of gluten-free tarhana soups prepared with different concentrations of QF (40%, 50%, and 60%). It was found that the soups fitted well (R2  > 0.99) Ostwald de Waele model and exhibited shear thinning behavior. Besides, elastic properties dominated the viscous properties. Although the maximum deformation and recovery were determined at 40% concentration level, minimum deformation and recovery properties were specified at 60% concentration level. The results suggest that QF can be used in gluten-free tarhana formulations to enhance rheological properties. Malnutrition is currently widespread in many areas of the world. Therefore, it must be focused on the cheap, but nutritious plant protein and mineral sources, such as legume and cereals. Several recent studies have showed the successful formulation of pseudocereal containing cereal based products. Tarhana is a traditional fermented food made of mainly a mixture cereal and yoghurt. Tarhana or tarhana-like products have been enriched or replaced with cereal and pseudocereal. In this research, the applicability of QF in traditional tarhana production were investigated. As a result, it is advisable to replace wheat flour with QF in products such as tarhana, couscous, noodle and pasta formulation for nutritional

  8. Confidence in generic drug substitution.

    Science.gov (United States)

    Lionberger, R; Jiang, W; Huang, S-M; Geba, G

    2013-10-01

    Patients should have confidence that the generic drugs they are prescribed in the United States can be effectively substituted for the brand product or another generic product. Through new bioequivalence study designs for narrow therapeutic index (NTI) drugs and postapproval studies of generic substitution, the US Food and Drug Administration's (FDA's) ongoing generic drug regulatory science activities are designed to ensure successful generic substitution for all drug products.

  9. Beyond hypercorrection: remembering corrective feedback for low-confidence errors.

    Science.gov (United States)

    Griffiths, Lauren; Higham, Philip A

    2017-07-01

    Correcting errors based on corrective feedback is essential to successful learning. Previous studies have found that corrections to high-confidence errors are better remembered than low-confidence errors (the hypercorrection effect). The aim of this study was to investigate whether corrections to low-confidence errors can also be successfully retained in some cases. Participants completed an initial multiple-choice test consisting of control, trick and easy general-knowledge questions, rated their confidence after answering each question, and then received immediate corrective feedback. After a short delay, they were given a cued-recall test consisting of the same questions. In two experiments, we found high-confidence errors to control questions were better corrected on the second test compared to low-confidence errors - the typical hypercorrection effect. However, low-confidence errors to trick questions were just as likely to be corrected as high-confidence errors. Most surprisingly, we found that memory for the feedback and original responses, not confidence or surprise, were significant predictors of error correction. We conclude that for some types of material, there is an effortful process of elaboration and problem solving prior to making low-confidence errors that facilitates memory of corrective feedback.

  10. Measurement of confidence: the development and psychometric evaluation of a stroke-specific, measure of confidence.

    Science.gov (United States)

    Horne, Jane C; Lincoln, Nadina B; Logan, Pip A

    2017-11-01

    To design, develop and psychometrically evaluate a stroke-specific measure of confidence, the Confidence after Stroke Measure (CaSM). Cross-sectional. Adults in the community. Stroke survivors and healthy elderly participants. Questionnaire items were generated based on the literature and qualitative interviews and piloted with expert groups to establish face validity. A 53-item CaSM was administered to stroke survivors and healthy elderly participants in the community. A second copy was posted four weeks later. Completed questionnaires were analysed for extreme responses, missing values, construct validity (factor analysis), convergent validity, divergent validity, reliability (internal consistency and temporal stability) and comparing responses according to age and gender. Stroke ( n = 101) and healthy elderly participants ( n = 101) returned questionnaires. Eight items were removed that had extreme responses and large numbers of missing values. Six items had item total correlations Confidence, Positive Attitude and Social Confidence, which explained 52% of variance. Cronbach's alpha coefficient demonstrated good internal consistency ( α = 0.94). A test re-test on the 27 items indicated good temporal stability ( r = 0.85, P = 0.001). The 27-item CaSM was a valid and reliable measure for assessing confidence in stroke survivors.

  11. Addressing the vaccine confidence gap.

    Science.gov (United States)

    Larson, Heidi J; Cooper, Louis Z; Eskola, Juhani; Katz, Samuel L; Ratzan, Scott

    2011-08-06

    Vaccines--often lauded as one of the greatest public health interventions--are losing public confidence. Some vaccine experts have referred to this decline in confidence as a crisis. We discuss some of the characteristics of the changing global environment that are contributing to increased public questioning of vaccines, and outline some of the specific determinants of public trust. Public decision making related to vaccine acceptance is neither driven by scientific nor economic evidence alone, but is also driven by a mix of psychological, sociocultural, and political factors, all of which need to be understood and taken into account by policy and other decision makers. Public trust in vaccines is highly variable and building trust depends on understanding perceptions of vaccines and vaccine risks, historical experiences, religious or political affiliations, and socioeconomic status. Although provision of accurate, scientifically based evidence on the risk-benefit ratios of vaccines is crucial, it is not enough to redress the gap between current levels of public confidence in vaccines and levels of trust needed to ensure adequate and sustained vaccine coverage. We call for more research not just on individual determinants of public trust, but on what mix of factors are most likely to sustain public trust. The vaccine community demands rigorous evidence on vaccine efficacy and safety and technical and operational feasibility when introducing a new vaccine, but has been negligent in demanding equally rigorous research to understand the psychological, social, and political factors that affect public trust in vaccines. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Interval Temporal Logics

    DEFF Research Database (Denmark)

    Monica, Dario Della; Goranko, Valentin; Montanari, Angelo

    2011-01-01

    We discuss a family of modal logics for reasoning about relational structures of intervals over (usually) linear orders, with modal operators associated with the various binary relations between such intervals, known as Allen’s interval relations. The formulae of these logics are evaluated at int...

  13. Confidence sets for network structure

    CERN Document Server

    Airoldi, Edoardo M; Wolfe, Patrick J

    2011-01-01

    Latent variable models are frequently used to identify structure in dichotomous network data, in part because they give rise to a Bernoulli product likelihood that is both well understood and consistent with the notion of exchangeable random graphs. In this article we propose conservative confidence sets that hold with respect to these underlying Bernoulli parameters as a function of any given partition of network nodes, enabling us to assess estimates of 'residual' network structure, that is, structure that cannot be explained by known covariates and thus cannot be easily verified by manual inspection. We demonstrate the proposed methodology by analyzing student friendship networks from the National Longitudinal Survey of Adolescent Health that include race, gender, and school year as covariates. We employ a stochastic expectation-maximization algorithm to fit a logistic regression model that includes these explanatory variables as well as a latent stochastic blockmodel component and additional node-specific...

  14. Confidence mediates the sex difference in mental rotation performance.

    Science.gov (United States)

    Estes, Zachary; Felker, Sydney

    2012-06-01

    On tasks that require the mental rotation of 3-dimensional figures, males typically exhibit higher accuracy than females. Using the most common measure of mental rotation (i.e., the Mental Rotations Test), we investigated whether individual variability in confidence mediates this sex difference in mental rotation performance. In each of four experiments, the sex difference was reliably elicited and eliminated by controlling or manipulating participants' confidence. Specifically, confidence predicted performance within and between sexes (Experiment 1), rendering confidence irrelevant to the task reliably eliminated the sex difference in performance (Experiments 2 and 3), and manipulating confidence significantly affected performance (Experiment 4). Thus, confidence mediates the sex difference in mental rotation performance and hence the sex difference appears to be a difference of performance rather than ability. Results are discussed in relation to other potential mediators and mechanisms, such as gender roles, sex stereotypes, spatial experience, rotation strategies, working memory, and spatial attention.

  15. Notes on interval estimation of the generalized odds ratio under stratified random sampling.

    Science.gov (United States)

    Lui, Kung-Jong; Chang, Kuang-Chao

    2013-05-01

    It is not rare to encounter the patient response on the ordinal scale in a randomized clinical trial (RCT). Under the assumption that the generalized odds ratio (GOR) is homogeneous across strata, we consider four asymptotic interval estimators for the GOR under stratified random sampling. These include the interval estimator using the weighted-least-squares (WLS) approach with the logarithmic transformation (WLSL), the interval estimator using the Mantel-Haenszel (MH) type of estimator with the logarithmic transformation (MHL), the interval estimator using Fieller's theorem with the MH weights (FTMH) and the interval estimator using Fieller's theorem with the WLS weights (FTWLS). We employ Monte Carlo simulation to evaluate the performance of these interval estimators by calculating the coverage probability and the average length. To study the bias of these interval estimators, we also calculate and compare the noncoverage probabilities in the two tails of the resulting confidence intervals. We find that WLSL and MHL can generally perform well, while FTMH and FTWLS can lose either precision or accuracy. We further find that MHL is likely the least biased. Finally, we use the data taken from a study of smoking status and breathing test among workers in certain industrial plants in Houston, Texas, during 1974 to 1975 to illustrate the use of these interval estimators.

  16. Reference intervals for biochemical blood variables, packed cell volume, and body temperature in pet rats (Rattus norvegicus) using point-of-care testing.

    Science.gov (United States)

    Houtmeyers, Anneleen; Duchateau, Luc; Grünewald, Bettina; Hermans, Katleen

    2016-12-01

    Rats (Rattus norvegicus) are increasingly kept as pets, thus more and more requiring veterinary care. Important differences exist between pet and laboratory rats, but little information is available on pet rats. Diagnosis and treatment of pet rat diseases would benefit from RIs specific for this animal population. The aim was to establish RIs for biochemical blood variables, PCV, and body temperature in pet rats. Additionally, influences of sex and feed rationing method (ad libitum, restricted) on these variables were determined. American Society for Veterinary Clinical Pathology (ASVCP) recommendations were followed. Biochemical variables were measured using an automated chemistry analyzer, the VetScan VS2. Nonparametric statistical methods were used to determine RIs and effects of sex and feed rationing method. Reference intervals were established using values of 123 clinically healthy pet rats (except for globulins and albumin/globulin ratio, n = 120) and were: glucose 6.6-13.7 mmol/L, total proteins 66-88 g/L, albumin ≥ 38 g/L, globulins 12-35 g/L, albumin/globulin ratio 1.0-4.7, urea nitrogen 2.5-6.6 mmol/L, creatinine ≤ 53 μmol/L, total bilirubin 4-7 μmol/L, ALP 40-442 IU/L, ALT 22-137 IU/L, amylase 502-1113 IU/L, sodium 133-144 mmol/L, potassium 3.6-5.3 mmol/L, calcium 9.5-10.9 mg/dL, phosphorus 2.3-7.0 mg/dL, PCV 40-50%, and body temperature 35.8-39.3°C. Sex significantly affected 10 variables. No significant influence was found with feed limitation CONCLUSIONS: Reference intervals reported in this study will be useful for interpretation of biochemistry analysis in pet rats and therefore improve pet rat medicine. © 2016 American Society for Veterinary Clinical Pathology.

  17. Confidence bounds for nonlinear dose-response relationships

    DEFF Research Database (Denmark)

    Baayen, C; Hougaard, P

    2015-01-01

    An important aim of drug trials is to characterize the dose-response relationship of a new compound. Such a relationship can often be described by a parametric (nonlinear) function that is monotone in dose. If such a model is fitted, it is useful to know the uncertainty of the fitted curve...... intervals for the dose-response curve. These confidence bounds have better coverage than Wald intervals and are more precise and generally faster than bootstrap methods. Moreover, if monotonicity is assumed, the profile likelihood approach takes this automatically into account. The approach is illustrated...

  18. Digitally Available Interval-Specific Rock-Sample Data Compiled from Historical Records, Nevada Test Site and Vicinity, Nye County, Nevada.

    Energy Technology Data Exchange (ETDEWEB)

    David B. Wood

    2007-10-24

    Between 1951 and 1992, 828 underground tests were conducted on the Nevada Test Site, Nye County, Nevada. Prior to and following these nuclear tests, holes were drilled and mined to collect rock samples. These samples are organized and stored by depth of borehole or drift at the U.S. Geological Survey Core Library and Data Center at Mercury, Nevada, on the Nevada Test Site. From these rock samples, rock properties were analyzed and interpreted and compiled into project files and in published reports that are maintained at the Core Library and at the U.S. Geological Survey office in Henderson, Nevada. These rock-sample data include lithologic descriptions, physical and mechanical properties, and fracture characteristics. Hydraulic properties also were compiled from holes completed in the water table. Rock samples are irreplaceable because pre-test, in-place conditions cannot be recreated and samples cannot be recollected from the many holes destroyed by testing. Documenting these data in a published report will ensure availability for future investigators.

  19. Digitally Available Interval-Specific Rock-Sample Data Compiled from Historical Records, Nevada Test Site and Vicinity, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    David B. Wood

    2009-10-08

    Between 1951 and 1992, underground nuclear weapons testing was conducted at 828 sites on the Nevada Test Site, Nye County, Nevada. Prior to and following these nuclear tests, holes were drilled and mined to collect rock samples. These samples are organized and stored by depth of borehole or drift at the U.S. Geological Survey Core Library and Data Center at Mercury, Nevada, on the Nevada Test Site. From these rock samples, rock properties were analyzed and interpreted and compiled into project files and in published reports that are maintained at the Core Library and at the U.S. Geological Survey office in Henderson, Nevada. These rock-sample data include lithologic descriptions, physical and mechanical properties, and fracture characteristics. Hydraulic properties also were compiled from holes completed in the water table. Rock samples are irreplaceable because pre-test, in-place conditions cannot be recreated and samples cannot be recollected from the many holes destroyed by testing. Documenting these data in a published report will ensure availability for future investigators.

  20. What about confidence intervals? : A word of caution when interpreting PTA simulations

    NARCIS (Netherlands)

    Colin, Pieter; Eleveld, Douglas J.; Jonckheere, Stijn; Van Bocxlaer, Jan; De Waele, Jan; Vermeulen, An

    In the field of antimicrobial chemotherapy, readers are increasingly confronted with population pharmacokinetic models and the ensuing simulation results with the purpose to improve the efficiency of currently used therapeutic regimens. One such type of analysis is Monte Carlo (MC) simulations in

  1. Variance estimates and confidence intervals for the Kappa measure of classification accuracy

    Science.gov (United States)

    M. A. Kalkhan; R. M. Reich; R. L. Czaplewski

    1997-01-01

    The Kappa statistic is frequently used to characterize the results of an accuracy assessment used to evaluate land use and land cover classifications obtained by remotely sensed data. This statistic allows comparisons of alternative sampling designs, classification algorithms, photo-interpreters, and so forth. In order to make these comparisons, it is...

  2. Young, Black, and Anxious: Describing the Black Student Mathematics Anxiety Research Using Confidence Intervals

    Science.gov (United States)

    Young, Jamaal Rashad; Young, Jemimah Lea

    2016-01-01

    In this article, the authors provide a single group summary using the Mathematics Anxiety Rating Scale (MARS) to characterize and delineate the measurement of mathematics anxiety (MA) reported among Black students. Two research questions are explored: (a) What are the characteristics of studies administering the MARS and its derivatives to…

  3. Computing confidence intervals on solution costs for stochastic grid generation expansion problems.

    Energy Technology Data Exchange (ETDEWEB)

    Woodruff, David L..; Watson, Jean-Paul

    2010-12-01

    A range of core operations and planning problems for the national electrical grid are naturally formulated and solved as stochastic programming problems, which minimize expected costs subject to a range of uncertain outcomes relating to, for example, uncertain demands or generator output. A critical decision issue relating to such stochastic programs is: How many scenarios are required to ensure a specific error bound on the solution cost? Scenarios are the key mechanism used to sample from the uncertainty space, and the number of scenarios drives computational difficultly. We explore this question in the context of a long-term grid generation expansion problem, using a bounding procedure introduced by Mak, Morton, and Wood. We discuss experimental results using problem formulations independently minimizing expected cost and down-side risk. Our results indicate that we can use a surprisingly small number of scenarios to yield tight error bounds in the case of expected cost minimization, which has key practical implications. In contrast, error bounds in the case of risk minimization are significantly larger, suggesting more research is required in this area in order to achieve rigorous solutions for decision makers.

  4. Technical Report on Modeling for Quasispecies Abundance Inference with Confidence Intervals from Metagenomic Sequence Data

    Energy Technology Data Exchange (ETDEWEB)

    McLoughlin, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-01-11

    The overall aim of this project is to develop a software package, called MetaQuant, that can determine the constituents of a complex microbial sample and estimate their relative abundances by analysis of metagenomic sequencing data. The goal for Task 1 is to create a generative model describing the stochastic process underlying the creation of sequence read pairs in the data set. The stages in this generative process include the selection of a source genome sequence for each read pair, with probability dependent on its abundance in the sample. The other stages describe the evolution of the source genome from its nearest common ancestor with a reference genome, breakage of the source DNA into short fragments, and the errors in sequencing the ends of the fragments to produce read pairs.

  5. Statistical Significance, Effect Size Reporting, and Confidence Intervals: Best Reporting Strategies

    Science.gov (United States)

    Capraro, Robert M.

    2004-01-01

    With great interest the author read the May 2002 editorial in the "Journal for Research in Mathematics Education (JRME)" (King, 2002) regarding changes to the 5th edition of the "Publication Manual of the American Psychological Association" (APA, 2001). Of special note to him, and of great import to the field of mathematics education research, are…

  6. Considering Teaching History and Calculating Confidence Intervals in Student Evaluations of Teaching Quality

    Science.gov (United States)

    Fraile, Rubén; Bosch-Morell, Francisco

    2015-01-01

    Lecturer promotion and tenure decisions are critical both for university management and for the affected lecturers. Therefore, they should be made cautiously and based on reliable information. Student evaluations of teaching quality are among the most used and analysed sources of such information. However, to date little attention has been paid in…

  7. P values and confidence intervals are reported in almost all scientific ...

    African Journals Online (AJOL)

    all scientific writings and are used in interpreting results of statistical analysis. It is usual for medical researchers and other investigators to ask questions such as 'Is the .... 1. Bamgboye EA 2002. A Companion of Medical. Statistics, 1st edition. Folbam publishers, Ibadan. 2. Kirkwood BR, Sterne JAC 2003 Essential medical.

  8. Approximate estimation of the derivative of a standard gamma quantile for use in confidence interval estimates

    Science.gov (United States)

    Hoshi, Kiyoshi; Burges, Stephen J.

    1981-10-01

    An approximation estimation technique for computing the derivative of a standard gamma quantile, w, with respect to the distribution shape parameter, b necessary for estimating the sampling variance of a specified quantile, is developed. The modified Wilson-Hilferty transformation parameters given by Kirby are approximated with fifth-order polynomials in skew coefficient, γ, facilitating direct estimation of ∂ω/∂β for continuous quantiles. Results are compared with more precise approximations of Harter's exact quantiles made by Bobée. The method presented provides excellent approximations corresponding to the probability range 0.001 ⩽ p ⩽ 0.999 for 0.6 ⩽ γ ⩽ 5 and satisfactory estimates of ∂ω/∂β for quantiles corresponding to 1 in 10- to 1 in 1000-yr. events for smaller γ.

  9. Optimizing lengths of confidence intervals: fourth-order efficiency in location models

    NARCIS (Netherlands)

    Klaassen, C.; Venetiaan, S.

    2010-01-01

    Under regularity conditions the maximum likelihood estimator of the location parameter in a location model is asymptotically efficient among translation equivariant estimators. Additional regularity conditions warrant third- and even fourth-order efficiency, in the sense that no translation

  10. Bayesian Methods and Confidence Intervals for Automatic Target Recognition of SAR Canonical Shapes

    Science.gov (United States)

    2014-03-27

    the Fubini Theorem ([14], pg. 61) to change the order of integration. Following [5], we will minimize the Bayes risk by minimizing the inner integral of...make use of the Rolle Theorem ([9], pg 20) which states that for any continuous function f (x) with roots a and b there exists a point a < ξ < b...second derivative F′′(x) has N − 1 roots and so on. The Nth derivative F (N)(x) has one root, ξ, and 16 by Rolle’s Theorem it is on the interior of the

  11. Effect of Traditional Aerobic Exercises Versus Sprint Interval Training on Pulmonary Function Tests In Young Sedentary Males: A Randomised Controlled Trial

    Science.gov (United States)

    Khaled M., Badaam; A., Munibuddin; S.T., Khan; S.P., Choudhari; R., Doiphode

    2013-01-01

    Background: Physical inactivity is now a global non-communicable disease. Current recommendations from American College of Sports Medicine, American Heart Association and UK medical officers for physical activity are difficult to implement, due to time constraints and hence, they have less compliance. Purpose: To compare Sprint Interval Training (SIT) and traditional aerobic exercise (AE) with respect to changes in Vital capacity (VC), Maximum Voluntary Ventilation (MVV) and Physical Fitness Index (PFI) in young sedentary males. Study Design: This was a randomised, controlled trial. Methods: Fourteen young, sedentary, healthy males who were aged 18-25 years were randomly allocated to SIT group and AE group for 3 weeks. SIT group exercised at high intensity for 10 minutes a day, three days a week. AE group exercised at moderate intensity for 30 minutes a day, five days a week. Results: Improvement in FVC (litres) in AE group was 0.31 ± 0.11 and that in SIT group was 0.48 ± 0.17. The improvement in MVV (litres) in AE Group was 21.5 ± 11.6 and that in SIT group was 27.77 ± 7.03. Thus, SIT showed a better improvement in primary outcome i.e. FVC and MVV, although difference in improvement was statistically not significant (p= 0.09 and 0.29 respectively). Secondary outcome i.e. PFI improved by 5.57 ± 1.71% in AE group and by 10.28 ± 3.03% in SIT group. The difference in improvement was statistically significant (p= 0.003). Conclusions: SIT can be suggested as a time efficient option for improving cardiorespiratory fitness and hence, it can be used as a health promotion strategy. PMID:24179890

  12. High Confidence Software and Systems Research Needs

    Data.gov (United States)

    Networking and Information Technology Research and Development, Executive Office of the President — This White Paper presents a survey of high confidence software and systems research needs. It has been prepared by the High Confidence Software and Systems...

  13. Survival outcome associated with the screening interval for gastric cancer in Korea.

    Science.gov (United States)

    Lee, Hyuk; Min, Byung-Hoon; Lee, Jun Haeng; Son, Hee Jung; Kim, Jae J; Rhee, Jong Chul; Kim, Seonwoo; Rhee, Poong-Lyul

    2011-01-01

    Early gastric cancer (EGC) can be treated by endoscopic resection, which results in an excellent prognosis. Optimal screening intervals considering risk factors for gastric cancer have not been established. The aim of this study was to determine the maximum gastric cancer screening interval in terms of long-term survival. Curative resection was performed in 561 patients with gastric cancer who had completed a questionnaire on their previous history of screening tests and risk factors. The association between EGC detection rate and previous screening history was evaluated, and 5-year disease-free survival rates were compared between various screening intervals. Multivariate analysis showed that intestinal metaplasia [hazard ratio (HR) 9.690, 95% confidence interval (CI) 5.896-15.927] and previous screening history (HR 0.077, 95% CI 0.048-0.125) were independent factors associated with advanced gastric cancer. In patients without intestinal metaplasia, there was no significant difference in the extent of gastric cancer progression and the 5-year disease-free survival rate between groups with screening intervals of less than 3 years. In patients with intestinal metaplasia, the cutoff screening interval for detection of EGC and disease-free survival was 2 years. The optimum screening interval for disease-free survival for gastric cancer in a normal population is 3 years, but a screening interval of 2 years should be used for patients with intestinal metaplasia in Korea. Copyright © 2011 S. Karger AG, Basel.

  14. Item-Specific Gender Differences in Confidence.

    Science.gov (United States)

    Foote, Chandra J.

    Very little research has been performed which examines gender differences in confidence in highly specified situations. More generalized studies consistently suggest that women are less confident than men (i.e. Sadker and Sadker, 1994). The few studies of gender differences in item-specific conditions indicate that men tend to be more confident in…

  15. The Structure of Public Confidence in Education.

    Science.gov (United States)

    Loveless, Tom

    1997-01-01

    Examines the loss of confidence in the educational system in juxtaposition with recent indicators showing growing confidence in the value of public schools. Explores ways of reconciling the conflicting evidence and argues the need for more sophisticated definition of public confidence in education. (GR)

  16. Understanding public confidence in government to prevent terrorist attacks.

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, T. E.; Ramaprasad, A,; Samsa, M. E.; Decision and Information Sciences; Univ. of Illinois at Chicago

    2008-04-02

    A primary goal of terrorism is to instill a sense of fear and vulnerability in a population and to erode its confidence in government and law enforcement agencies to protect citizens against future attacks. In recognition of its importance, the Department of Homeland Security includes public confidence as one of the principal metrics used to assess the consequences of terrorist attacks. Hence, a detailed understanding of the variations in public confidence among individuals, terrorist event types, and as a function of time is critical to developing this metric. In this exploratory study, a questionnaire was designed, tested, and administered to small groups of individuals to measure public confidence in the ability of federal, state, and local governments and their public safety agencies to prevent acts of terrorism. Data was collected from three groups before and after they watched mock television news broadcasts portraying a smallpox attack, a series of suicide bomber attacks, a refinery explosion attack, and cyber intrusions on financial institutions, resulting in identity theft. Our findings are: (a) although the aggregate confidence level is low, there are optimists and pessimists; (b) the subjects are discriminating in interpreting the nature of a terrorist attack, the time horizon, and its impact; (c) confidence recovery after a terrorist event has an incubation period; and (d) the patterns of recovery of confidence of the optimists and the pessimists are different. These findings can affect the strategy and policies to manage public confidence after a terrorist event.

  17. Haemostatic reference intervals in pregnancy

    DEFF Research Database (Denmark)

    Szecsi, Pal Bela; Jørgensen, Maja; Klajnbard, Anna

    2010-01-01

    -specific reference intervals for coagulation tests during normal pregnancy. Eight hundred one women with expected normal pregnancies were included in the study. Of these women, 391 had no complications during pregnancy, vaginal delivery, or postpartum period. Plasma samples were obtained at gestational weeks 13...... protein S was stable. Gestational age-specific reference values are essential for the accurate interpretation of a subset of haemostatic tests during pregnancy, delivery, and puerperium.......Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age...

  18. Electrocardiographic intervals associated with incident atrial fibrillation: Dissecting the QT interval.

    Science.gov (United States)

    Roberts, Jason D; Soliman, Elsayed Z; Alonso, Alvaro; Vittinghoff, Eric; Chen, Lin Y; Loehr, Laura; Marcus, Gregory M

    2017-05-01

    Prolongation of the QT interval has been associated with an increased risk of developing atrial fibrillation (AF), but the responsible mechanism remains unknown. The aims of this study were to subdivide the QT interval into its components and identify the resultant electrocardiographic interval(s) responsible for the association with AF. Predefined QT-interval components were assessed for association with incident AF in the Atherosclerosis Risk in Communities study using Cox proportional hazards models. Hazard ratios (HRs) were calculated per 1-SD increase in each component. Among QT-interval components exhibiting significant associations, additional analyses evaluating long extremes, defined as greater than the 95th percentile, were performed. Of the 14,625 individuals, 1505 (10.3%) were diagnosed with incident AF during a mean follow-up period of 17.6 years. After multivariable adjustment, QT-interval components involved in repolarization, but not depolarization, exhibited significant associations with incident AF, including a longer ST segment (HR 1.27; 95% confidence interval [CI] 1.14-1.41; P QT interval and incident AF is primarily explained by components involved in ventricular repolarization: prolongation of the ST segment and T-onset to T-peak. These observations suggest that prolongation of phases 2 and 3 of the cardiac action potential drives the association between the QT interval and AF risk. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  19. With long intervals, inter-stimulus interval is the critical determinant of P300 amplitude

    NARCIS (Netherlands)

    Sambeth, A.; Maes, J.H.R.; Brankack, J.

    2004-01-01

    Previous research, using short inter-stimulus intervals (1-4 s), suggests that the P300 of the human event-related potential during oddball and single-stimulus tasks is mainly affected by target-to-target interval (TTI). The present study tested the validity of this claim at longer intervals in a

  20. Sex differences in confidence influence patterns of conformity.

    Science.gov (United States)

    Cross, Catharine P; Brown, Gillian R; Morgan, Thomas J H; Laland, Kevin N

    2017-11-01

    Lack of confidence in one's own ability can increase the likelihood of relying on social information. Sex differences in confidence have been extensively investigated in cognitive tasks, but implications for conformity have not been directly tested. Here, we tested the hypothesis that, in a task that shows sex differences in confidence, an indirect effect of sex on social information use will also be evident. Participants (N = 168) were administered a mental rotation (MR) task or a letter transformation (LT) task. After providing an answer, participants reported their confidence before seeing the responses of demonstrators and being allowed to change their initial answer. In the MR, but not the LT, task, women showed lower levels of confidence than men, and confidence mediated an indirect effect of sex on the likelihood of switching answers. These results provide novel, experimental evidence that confidence is a general explanatory mechanism underpinning susceptibility to social influences. Our results have implications for the interpretation of the wider literature on sex differences in conformity. © 2016 The British Psychological Society.

  1. Test-retest reproducibility of elbow goniometric measurements in a rigid double-blinded protocol: intervals for distinguishing between measurement error and clinical change.

    Science.gov (United States)

    Cleffken, Berry; van Breukelen, Gerard; van Mameren, Henk; Brink, Peter; Olde Damink, Steven

    2007-01-01

    Increasingly, goniometry of elbow motion is used for qualification of research results. Expression of reliability is in parameters not suitable for comparison of results. We modified Bland and Altman's method, resulting in the smallest detectable differences (SDDs). Two raters measured elbow excursions in 42 individuals (144 ratings per test person) with an electronic digital inclinometer in a classical test-retest crossover study design. The SDDs were 0 +/- 4.2 degrees for active extension; 0 +/- 8.2 degrees for active flexion, both without upper arm fixation; 0 +/- 6.3 degrees for active extension; 0 +/- 5.7 degrees for active flexion; 0 +/- 7.4 degrees for passive flexion with upper arm fixation; 0 +/- 10.1 degrees for active flexion with upper arm retroflexion; and 0 +/- 8.5 degrees and 0 +/- 10.8 degrees for active and passive range of motion. Differences smaller than these SDDs found in clinical or research settings are attributable to measurement error and do not indicate improvement.

  2. Confidence in breastfeeding among pregnant women.

    Science.gov (United States)

    Laanterä, Sari; Pietilä, Anna-Maija; Ekström, Anette; Pölkki, Tarja

    2012-11-01

    Little is known about prenatal breastfeeding confidence, although such knowledge is necessary for developing the content of counseling and tailoring it for individuals. The purpose of this study was to describe women's prenatal breastfeeding confidence and how their sociodemographic characteristics, breastfeeding knowledge, and attitudes relate to it. The electronic confidence scale was used in data collection, and 123 Finnish women filled in the questionnaire. The mean confidence score was 83.88 when the maximum possible score was 120. Confidence scores varied when parity, breastfeeding knowledge, and attitudes were involved. Variables regarding breastfeeding as difficult, regarding breastfeeding as exhausting, and parity explained 38.1% of the variation of the breastfeeding confidence scores. Pregnant women need information about managing potential breastfeeding problems and the physiology of breastfeeding. Interventions designed to promote breastfeeding confidence need to be focused on primiparas and women with a lack of breastfeeding knowledge.

  3. Haemostatic reference intervals in pregnancy

    DEFF Research Database (Denmark)

    Szecsi, Pal Bela; Jørgensen, Maja; Klajnbard, Anna

    2010-01-01

    Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age-specific refe......Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age......-specific reference intervals for coagulation tests during normal pregnancy. Eight hundred one women with expected normal pregnancies were included in the study. Of these women, 391 had no complications during pregnancy, vaginal delivery, or postpartum period. Plasma samples were obtained at gestational weeks 13......-20, 21-28, 29-34, 35-42, at active labor, and on postpartum days 1 and 2. Reference intervals for each gestational period using only the uncomplicated pregnancies were calculated in all 391 women for activated partial thromboplastin time (aPTT), fibrinogen, fibrin D-dimer, antithrombin, free protein S...

  4. Application of Student t-test for evaluation of interlaboratory comparative tests results

    Directory of Open Access Journals (Sweden)

    K. V. Shatalov

    2016-01-01

    Full Text Available The results of interlaboratory comparative tests typically represent a small sample size. Therefore, to evaluate the quality of test results of laboratories participating in interlaboratory comparative tests, it is proposed to use Student t-test, which connects three main characteristics of small sample: the width of the confidence interval, the corresponding confidence probability and sample size. The examples of interlaboratory comparative tests of diesel show, that the use Student test allows to more objectively evaluate the quality of tests results of laboratories, in particular to identify and assess the results outside the confidence interval of the certified value of the sample for inspection. The calculation of average values of Student statistic for the aggregate test results allows to evaluate the quality of the laboratory, to range them, to form a ranking of laboratories on an objective basis.

  5. Overconfidence in Interval Estimates: What Does Expertise Buy You?

    Science.gov (United States)

    McKenzie, Craig R. M.; Liersch, Michael J.; Yaniv, Ilan

    2008-01-01

    People's 90% subjective confidence intervals typically contain the true value about 50% of the time, indicating extreme overconfidence. Previous results have been mixed regarding whether experts are as overconfident as novices. Experiment 1 examined interval estimates from information technology (IT) professionals and UC San Diego (UCSD) students…

  6. A confidence-limit-based approach to the assessment of Hardy-Weinberg equilibrium.

    Science.gov (United States)

    Wellek, Stefan; Goddard, Katrina A B; Ziegler, Andreas

    2010-04-01

    The classical chi(2)-procedure for the assessment of Hardy-Weinberg equilibrium (HWE) is tailored for detecting violations of HWE. However, many applications in genetic epidemiology require approximate compatibility with HWE. In a previous contribution to the field (Wellek, S. (2004). Biometrics, 60, 694-703), the methodology of statistical equivalence testing was exploited for the construction of tests for problems in which the assumption of approximate compatibility of a given genotype distribution with HWE plays the role of the alternative hypothesis one aims to establish. In this article, we propose a procedure serving the same purpose but relying on confidence limits rather than critical bounds of a significance test. Interval estimation relates to essentially the same parametric function that was previously chosen as the target parameter for constructing an exact conditional UMPU test for equivalence with a HWE conforming genotype distribution. This population parameter is shown to have a direct genetic interpretation as a measure of relative excess heterozygosity. Confidence limits are constructed using both asymptotic and exact methods. The new approach is illustrated by reanalyzing genotype distributions obtained from published genetic association studies, and detailed guidance for choosing the equivalence margin is provided. The methods have been implemented in freely available SAS macros.

  7. Knee Confidence as It Relates to Self-reported and Objective Correlates of Knee Osteoarthritis: A Cross-sectional Study of 220 Patients.

    Science.gov (United States)

    Skou, Søren T; Rasmussen, Sten; Simonsen, Ole; Roos, Ewa M

    2015-10-01

    Cross-sectional study. The objective was to validate, if possible, previously reported associations and to investigate other potential associations between knee confidence and various self-reported and objective measures in an independent cohort of patients with knee osteoarthritis (OA). Lack of knee confidence is a frequent symptom in patients with knee OA, but little is known of associations between knee confidence and other common correlates of knee OA. Baseline data from 220 patients with knee OA were applied in ordinal regression analyses, with knee confidence, assessed using item Q3 of the Knee injury and Osteoarthritis Outcome Score, as the dependent variable and self-reported (pain on walking, general health, fear of movement, self-efficacy, function, and previous serious injury) and objective measures (muscle strength, 20-m walk time, and radiographic severity of tibiofemoral OA) as predictor variables. Most (95%) of the participants reported lack of knee confidence, and 54% experienced severe or extreme lack of knee confidence. Fear of movement (odds ratio [OR] = 2.06; 95% confidence interval [CI]: 1.15, 3.68), pain on walking (OR = 1.21; 95% CI: 1.09, 1.34), and general health (OR = 0.024; 95% CI: 0.002, 0.259) explained 19% of the variance in knee confidence (Pconfidence is a common finding in individuals with knee OA. Pain on walking was confirmed as a correlate of knee confidence, whereas muscle strength was not. Fear of movement and poor general health were new variables associated with lack of knee confidence. The noncorrelations or poor correlations with other tested variables suggest that a lack of knee confidence may represent an independent treatment target in knee OA of importance to improve mobility. Trials registered at ClinicalTrials.gov (NCT01410409 and NCT01535001).

  8. Design and Operation of a Borehole Straddle Packer for Ground-Water Sampling and Hydraulic Testing of Discrete Intervals at U.S. Air Force Plant 6, Marietta, Georgia

    Science.gov (United States)

    Holloway, Owen G.; Waddell, Jonathan P.

    2008-01-01

    A borehole straddle packer was developed and tested by the U.S. Geological Survey to characterize the vertical distribution of contaminants, head, and hydraulic properties in open-borehole wells as part of an ongoing investigation of ground-water contamination at U.S. Air Force Plant 6 (AFP6) in Marietta, Georgia. To better understand contaminant fate and transport in a crystalline bedrock setting and to support remedial activities at AFP6, numerous wells have been constructed that include long open-hole intervals in the crystalline bedrock. These wells can include several discontinuities that produce water, which may contain contaminants. Because of the complexity of ground-water flow and contaminant movement in the crystalline bedrock, it is important to characterize the hydraulic and water-quality characteristics of discrete intervals in these wells. The straddle packer facilitates ground-water sampling and hydraulic testing of discrete intervals, and delivery of fluids including tracer suites and remedial agents into these discontinuities. The straddle packer consists of two inflatable packers, a dual-pump system, a pressure-sensing system, and an aqueous injection system. Tests were conducted to assess the accuracy of the pressure-sensing systems, and water samples were collected for analysis of volatile organic compound (VOCs) concentrations. Pressure-transducer readings matched computed water-column height, with a coefficient of determination of greater than 0.99. The straddle packer incorporates both an air-driven piston pump and a variable-frequency, electronic, submersible pump. Only slight differences were observed between VOC concentrations in samples collected using the two different types of sampling pumps during two sampling events in July and August 2005. A test conducted to assess the effect of stagnation on VOC concentrations in water trapped in the system's pump-tubing reel showed that concentrations were not affected. A comparison was conducted

  9. Regional Competition for Confidence: Features of Formation

    Directory of Open Access Journals (Sweden)

    Irina Svyatoslavovna Vazhenina

    2016-09-01

    Full Text Available The increase in economic independence of the regions inevitably leads to an increase in the quality requirements of the regional economic policy. The key to successful regional policy, both during its development and implementation, is the understanding of the necessity of gaining confidence (at all levels, and the inevitable participation in the competition for confidence. The importance of confidence in the region is determined by its value as a competitive advantage in the struggle for partners, resources and tourists, and attracting investments. In today’s environment the focus of governments, regions and companies on long-term cooperation is clearly expressed, which is impossible without a high level of confidence between partners. Therefore, the most important competitive advantages of territories are intangible assets such as an attractive image and a good reputation, which builds up confidence of the population and partners. The higher the confidence in the region is, the broader is the range of potential partners, the larger is the planning horizon of long-term concerted action, the better are the chances of acquiring investment, the higher is the level of competitive immunity of the territories. The article defines competition for confidence as purposeful behavior of a market participant in economic environment, aimed at acquiring specific intangible competitive advantage – the confidence of the largest possible number of other market actors. The article also highlights the specifics of confidence as a competitive goal, presents factors contributing to the destruction of confidence, proposes a strategy to fight for confidence as a program of four steps, considers the factors which integrate regional confidence and offers several recommendations for the establishment of effective regional competition for confidence

  10. Inter-Pregnancy Interval

    African Journals Online (AJOL)

    Buchi

    optimal interval after which they can conceive especially if the previous birth was by caesarean ... after termination of pregnancy (as early as 14 days). 6 than do women who deliver at term. Majority of these .... Contraceptive Pills (COCPs) are commenced at 6 months post partum in a breast feeding mother because the ...

  11. Product interval automata

    Indian Academy of Sciences (India)

    We identify a subclass of timed automata called product interval automata and develop its theory. These automata consist of a network of timed agents with the key restriction being that there is just one clock for each agent and the way the clocks are read and reset is determined by the distribution of shared actions across ...

  12. Product interval automata

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    in both logical and language theoretic terms. We also show that product interval automata are expressive enough to model the timed behaviour of asynchronous digital circuits. Keywords. Timed automata; distributed systems; logic. 1. Introduction. Timed automata as formulated by Alur & Dill (1994) have become a canonical ...

  13. Confidence in Forced-Choice Recognition: What Underlies the Ratings?

    Science.gov (United States)

    Zawadzka, Katarzyna; Higham, Philip A.; Hanczakowski, Maciej

    2017-01-01

    Two-alternative forced-choice recognition tests are commonly used to assess recognition accuracy that is uncontaminated by changes in bias. In such tests, participants are asked to endorse the studied item out of 2 presented alternatives. Participants may be further asked to provide confidence judgments for their recognition decisions. It is often…

  14. Highly Confident Wrong Answering--And How to Detect It.

    Science.gov (United States)

    Yule, George

    1988-01-01

    A Confidence-rating scale accompanying answers on a listening test helps distinguish between learners who select answers based on effective self-monitoring and those whose answers are based on poor self-monitoring. The latter are more likely to do so subsequently as well. Test items and a rating scale are illustrated. (Author/LMO)

  15. Comparative study of Weibull characteristic strength and mean strength of GPCs to confirm the minimum number of samples needed for confident strength reporting.

    Science.gov (United States)

    Mehrvar, Cina; Curran, Declan J; Alhalawani, Adel M F; Boyd, Daniel; Towler, Mark

    2015-03-01

    This short communication determines the strength of two glass polyalkenoate cements that differ from each other through the composition of their glass phase. Sample sets of n=5, 10, 20 and 30 were formulated and tested in biaxial flexure. The derived mean for each sample set was compared against the Weibull characteristic strength. The mean and corresponding characteristic strength show a maximum percentage difference 10.1%, and the 95% confidence intervals calculated from the mean data encompass the corresponding characteristic strength down to a sample set of n=5. This suggests that, for brittle materials such as glass polyalkenoate cements, it is acceptable to test only five samples of each material in biaxial flexure and the resultant 95% confidence intervals will encompass the corresponding Weibull characteristic strength of the material. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Sample Size Calculation for Estimating or Testing a Nonzero Squared Multiple Correlation Coefficient

    Science.gov (United States)

    Krishnamoorthy, K.; Xia, Yanping

    2008-01-01

    The problems of hypothesis testing and interval estimation of the squared multiple correlation coefficient of a multivariate normal distribution are considered. It is shown that available one-sided tests are uniformly most powerful, and the one-sided confidence intervals are uniformly most accurate. An exact method of calculating sample size to…

  17. Feature Selection Based on Confidence Machine

    OpenAIRE

    Liu, Chang; Xu, Yi

    2014-01-01

    In machine learning and pattern recognition, feature selection has been a hot topic in the literature. Unsupervised feature selection is challenging due to the loss of labels which would supply the related information.How to define an appropriate metric is the key for feature selection. We propose a filter method for unsupervised feature selection which is based on the Confidence Machine. Confidence Machine offers an estimation of confidence on a feature'reliability. In this paper, we provide...

  18. A model for developing disability confidence.

    Science.gov (United States)

    Lindsay, Sally; Cancelliere, Sara

    2017-05-15

    Many clinicians, educators, and employers lack disability confidence which can affect their interactions with, and inclusion of people with disabilities. Our objective was to explore how disability confidence developed among youth who volunteered with children who have a disability. We conducted 30 in-depth interviews (16 without a disability, 14 with disabilities), with youth aged 15-25. We analyzed our data using an interpretive, qualitative, thematic approach. We identified four main themes that led to the progression of disability confidence including: (1) "disability discomfort," referring to lacking knowledge about disability and experiencing unease around people with disabilities; (2) "reaching beyond comfort zone" where participants increased their understanding of disability and became sensitized to difference; (3) "broadened perspectives" where youth gained exposure to people with disabilities and challenged common misperceptions and stereotypes; and (4) "disability confidence" which includes having knowledge of people with disabilities, inclusive, and positive attitudes towards them. Volunteering is one way that can help to develop disability confidence. Youth with and without disabilities both reported a similar process of developing disability confidence; however, there were nuances between the two groups. Implications for Rehabilitation The development of disability confidence is important for enhancing the social inclusion of people with disabilities. Volunteering with people who have a disability, or a disability different from their own, can help to develop disability confidence which involves positive attitudes, empathy, and appropriate communication skills. Clinicians, educators, and employers should consider promoting working with disabled people through such avenues as volunteering or service learning to gain disability confidence.

  19. Cross-cultural adaptation and validation of the Karitane Parenting Confidence Scale of maternal confidence assessment for use in Brazil.

    Science.gov (United States)

    Pereira, Lívia W; Bernardi, Juliana R; Matos, Salete de; Silva, Clecio H da; Goldani, Marcelo Z; Bosa, Vera L

    2017-08-23

    To transculturally adapt and validate the Karitane Parenting Confidence Scale to the Brazilian Portuguese language and culture and verify the combination of the results with the maternal sociodemographic characteristics. This is a validation and transcultural adaptation nestled in a longitudinal and observational study in Porto Alegre, RS, Brazil, assessing mother-infant pairs from different gestational and perinatal environments. The original authors authorized the translation into Brazilian Portuguese, unified version creation, back-translation, analysis by specialists, final version implementation, and acceptance. Cronbach's alpha analysis was performed. The Kruskal-Wallis test with post-hoc Dunn's test was used to compare the study groups. Socioeconomic and demographic characteristics, obtained through a questionnaire in the first 24-48h of the newborns' life, were associated with maternal results by the Brazilian version of the scale, using Spearman's correlation and Mann-Whitney's test. The sample consisted of 251 postpartum women, with the confidence maternal questionnaire being applied at 15 days postpartum. The median score of the mothers' confidence was 40.00 (37.00-43.00). The protocol obtained a Cronbach's alpha of 0.717. There were significant weak positive correlations between maternal confidence and age (p=0.013, r=0.157) and between maternal confidence and schooling (p=0.048, r=0.125). Additionally, a significant association was observed between maternal confidence and parity (p=0.030). The transcultural adaptation and validation of the confidence maternal questionnaire into Brazilian Portuguese language and culture showed good reliability for this sample. The results of its use demonstrated that maternal confidence was associated with schooling, age and parity. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  20. Optimal prediction intervals of wind power generation

    DEFF Research Database (Denmark)

    Wan, Can; Wu, Zhao; Pinson, Pierre

    2014-01-01

    Accurate and reliable wind power forecasting is essential to power system operation. Given significant uncertainties involved in wind generation, probabilistic interval forecasting provides a unique solution to estimate and quantify the potential impacts and risks facing system operation with wind...... penetration beforehand. This paper proposes a novel hybrid intelligent algorithm approach to directly formulate optimal prediction intervals of wind power generation based on extreme learning machine and particle swarm optimization. Prediction intervals with Associated confidence levels are generated through...... conducted. Comparing with benchmarks applied, experimental results demonstrate the high efficiency and reliability of the developed approach. It is therefore convinced that the proposed method provides a new generalized framework for probabilistic wind power forecasting with high reliability and flexibility...

  1. Food skills confidence and household gatekeepers' dietary practices.

    Science.gov (United States)

    Burton, Melissa; Reid, Mike; Worsley, Anthony; Mavondo, Felix

    2017-01-01

    Household food gatekeepers have the potential to influence the food attitudes and behaviours of family members, as they are mainly responsible for food-related tasks in the home. The aim of this study was to determine the role of gatekeepers' confidence in food-related skills and nutrition knowledge on food practices in the home. An online survey was completed by 1059 Australian dietary gatekeepers selected from the Global Market Insite (GMI) research database. Participants responded to questions about food acquisition and preparation behaviours, the home eating environment, perceptions and attitudes towards food, and demographics. Two-step cluster analysis was used to identify groups based on confidence regarding food skills and nutrition knowledge. Chi-square tests and one-way ANOVAs were used to compare the groups on the dependent variables. Three groups were identified: low confidence, moderate confidence and high confidence. Gatekeepers in the highest confidence group were significantly more likely to report lower body mass index (BMI), and indicate higher importance of fresh food products, vegetable prominence in meals, product information use, meal planning, perceived behavioural control and overall diet satisfaction. Gatekeepers in the lowest confidence group were significantly more likely to indicate more perceived barriers to healthy eating, report more time constraints and more impulse purchasing practices, and higher convenience ingredient use. Other smaller associations were also found. Household food gatekeepers with high food skills confidence were more likely to engage in several healthy food practices, while those with low food skills confidence were more likely to engage in unhealthy food practices. Food education strategies aimed at building food-skills and nutrition knowledge will enable current and future gatekeepers to make healthier food decisions for themselves and for their families. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Applications of interval computations

    CERN Document Server

    Kreinovich, Vladik

    1996-01-01

    Primary Audience for the Book • Specialists in numerical computations who are interested in algorithms with automatic result verification. • Engineers, scientists, and practitioners who desire results with automatic verification and who would therefore benefit from the experience of suc­ cessful applications. • Students in applied mathematics and computer science who want to learn these methods. Goal Of the Book This book contains surveys of applications of interval computations, i. e. , appli­ cations of numerical methods with automatic result verification, that were pre­ sented at an international workshop on the subject in EI Paso, Texas, February 23-25, 1995. The purpose of this book is to disseminate detailed and surveyed information about existing and potential applications of this new growing field. Brief Description of the Papers At the most fundamental level, interval arithmetic operations work with sets: The result of a single arithmetic operation is the set of all possible results as the o...

  3. Depression and self-care maintenance in patients with heart failure: A moderated mediation model of self-care confidence and resilience.

    Science.gov (United States)

    Chang, Ling-Yin; Wu, Shan-Ying; Chiang, Chern-En; Tsai, Pei-Shan

    2017-06-01

    Despite the recognition of the negative effects of depressive symptoms on self-care confidence and self-care maintenance in patients with heart failure, little is known about the moderating role of resilience underlying these relations. To explore whether depressive symptoms affect self-care maintenance through self-care confidence and whether this mediating process was moderated by resilience. The sample comprised 201 community-dwelling and medically stable patients with echocardiographically documented heart failure. A moderated mediation model was conducted to test whether self-care confidence mediated the association between depressive symptoms and self-care maintenance, and whether resilience moderated the direct and indirect effects of depressive symptoms after adjustment for covariates. Depressive symptoms reduced self-care maintenance indirectly by decreasing self-care confidence (indirect effect: -0.22, 95% confidence interval: -0.36, -0.11), and this pathway was only significant for patients with moderate and high levels and not with low levels of resilience. Resilience also moderated the direct effects of depressive symptoms on self-care maintenance such that the negative association between depressive symptoms and self-care maintenance was reversed by the existence of high resilience. Resilience moderated the direct and indirect effects of depressive symptoms through self-care confidence on self-care maintenance in heart failure patients. Efforts to improve self-care maintenance by targeting depressive symptoms may be more effective when considering self-care confidence in patients with moderate to high levels of resilience.

  4. Confidence rating of marine eutrophication assessments

    DEFF Research Database (Denmark)

    Murray, Ciarán; Andersen, Jesper Harbo; Kaartokallio, Hermanni

    2011-01-01

    This report presents the development of a methodology for assessing confidence in eutrophication status classifications. The method can be considered as a secondary assessment, supporting the primary assessment of eutrophication status. The confidence assessment is based on a transparent scoring ...... of the marine environment....

  5. Aging and Confidence Judgments in Item Recognition

    Science.gov (United States)

    Voskuilen, Chelsea; Ratcliff, Roger; McKoon, Gail

    2018-01-01

    We examined the effects of aging on performance in an item-recognition experiment with confidence judgments. A model for confidence judgments and response time (RTs; Ratcliff & Starns, 2013) was used to fit a large amount of data from a new sample of older adults and a previously reported sample of younger adults. This model of confidence…

  6. Building Scientific Confidence in the Development and ...

    Science.gov (United States)

    Building Scientific Confidence in the Development and Evaluation of Read-Across Using Tox21 Approaches Slide presentation at GlobalChem conference and workshop in Washington, DC on Case Study on Building Scientific Confidence in the Development and Evaluation of Read-Across Using Tox21 Approaches

  7. Self-Confidence in the Hospitality Industry

    Directory of Open Access Journals (Sweden)

    Michael Oshins

    2014-02-01

    Full Text Available Few industries rely on self-confidence to the extent that the hospitality industry does because guests must feel welcome and that they are in capable hands. This article examines the results of hundreds of student interviews with industry professionals at all levels to determine where the majority of the hospitality industry gets their self-confidence.

  8. Financial Literacy, Confidence and Financial Advice Seeking

    NARCIS (Netherlands)

    Kramer, Marc M.

    2016-01-01

    We find that people with higher confidence in their own financial literacy are less likely to seek financial advice, but no relation between objective measures of literacy and advice seeking. The negative association between confidence and advice seeking is more pronounced among wealthy households.

  9. Consumer Confidence or the Business Cycle

    DEFF Research Database (Denmark)

    Møller, Stig V.; Nørholm, Henrik; Rangvid, Jesper

    2014-01-01

    Answer: The business cycle. We show that consumer confidence and the output gap both affect excess returns on stocks in many European countries: When the output gap is positive (the economy is doing well), expected returns are low, and when consumer confidence is high, expected returns are also low...... is better captured when using the European output gap as a risk factor....

  10. Examining Response Confidence in Multiple Text Tasks

    Science.gov (United States)

    List, Alexandra; Alexander, Patricia A.

    2015-01-01

    Students' confidence in their responses to a multiple text-processing task and their justifications for those confidence ratings were investigated. Specifically, 215 undergraduates responded to two academic questions, differing by type (i.e., discrete and open-ended) and by domain (i.e., developmental psychology and astrophysics), using a digital…

  11. Application of Interval Arithmetic in the Evaluation of Transfer Capabilities by Considering the Sources of Uncertainty

    Directory of Open Access Journals (Sweden)

    Prabha Umapathy

    2009-01-01

    Full Text Available Total transfer capability (TTC is an important index in a power system with large volume of inter-area power exchanges. This paper proposes a novel technique to determine the TTC and its confidence intervals in the system by considering the uncertainties in the load and line parameters. The optimal power flow (OPF method is used to obtain the TTC. Variations in the load and line parameters are incorporated using the interval arithmetic (IA method. The IEEE 30 bus test system is used to illustrate the proposed methodology. Various uncertainties in the line, load and both line and load are incorporated in the evaluation of total transfer capability. From the results, it is observed that the solutions obtained through the proposed method provide much wider information in terms of closed interval form which is more useful in ensuring secured operation of the interconnected system in the presence of uncertainties in load and line parameters.

  12. Towards better counselling. Keeping confidences. Training activities.

    Science.gov (United States)

    1996-01-01

    Presented are two training exercises for health personnel who counsel individuals about the results of blood tests for human immunodeficiency virus (HIV). The first exercise is preceded by remarks on the importance of trust and confidentiality in the clinical encounter. Then, participants are divided into pairs and instructed to think of a person they trust and to list 10 characteristics of that person. These attributes are compiled for the entire group. Next, small groups of 3-4 participants discuss the following questions: What do you need to say and do when you are counseling someone to help them have confidence in you? What do you need to do to enable them to keep trusting you? What might happen when confidentiality is broken? What are the benefits of maintaining confidentiality? Finally, the small groups are given case scenarios of breaches of client confidentiality and asked to imagine both how they would feel in such a situation and how it could have been prevented. The second exercise seeks to increase counselors' understanding of clients' risk-taking behaviors and their ability to suspend personal judgment by having them describe incidents from their own lives when they took a risk related to sex, relationships, or money.

  13. Concurrent Training in Rugby Sevens: Effects of High-Intensity Interval Exercises.

    Science.gov (United States)

    Robineau, Julien; Lacome, Mathieu; Piscione, Julien; Bigard, Xavier; Babault, Nicolas

    2017-03-01

    To assess the impact of 2 high-intensity interval-training (HIT) programs (short interval vs sprint interval training) on muscle strength and aerobic performances in a concurrent training program in amateur rugby sevens players. Thirty-six amateur rugby sevens players were randomly assigned to strength and short interval training (INT), strength and sprint interval training (SIT), or a strength-only training group (CON) during an 8-wk period. Maximal strength and power tests, aerobic measurements (peak oxygen uptake [VO2peak] and maximal aerobic velocity), and a specific repeated-sprint ability (RSA) test were conducted before and immediately after the overall training period. From magnitude-based inference and effect size (ES ± 90% confidence limit) analyses, the current study revealed substantial gains in maximal strength and jump-height performance in all groups. The difference in change of slow concentric torque production was greater in CON than in SIT (0.65 ± 0.72, moderate). VO2peak and, consequently, mean performance in the RSA test were improved in the SIT group only (0.64 ± 0.29, moderate; -0.54 ± 0.35, moderate). The study did not emphasize interference on strength development after INT but showed a slight impairment of slow concentric torque production gains after SIT. Compared with INT, SIT would appear to be more effective to develop VO2peak and RSA but could induce lower muscle-strength gains, especially at low velocity.

  14. Exploring Self - Confidence Level of High School Students Doing Sport

    Directory of Open Access Journals (Sweden)

    Nurullah Emir Ekinci

    2014-10-01

    Full Text Available The aim of this study was to investigate self-confidence levels of high school students, who do sport, in the extent of their gender, sport branch (individual/team sports and aim for participating in sport (professional/amateur. 185 active high school students from Kutahya voluntarily participated for the study. In the study as data gathering tool self-confidence scale was used. In the evaluation of the data as a hypothesis test Mann Whitney U non parametric test was used. As a result self-confidence levels of participants showed significant differences according to their gender and sport branch but there was no significant difference according to aim for participating in sport.

  15. Association Between Confidence in Smiling and Esthetic Characteristics.

    Science.gov (United States)

    Muniz, Francisco Wilker Mustafa Gomes; Cavalcante, Denise Juaçaba; Moreira, Maria Mônica Studart Mendes; Rodrigues, Lidiany Karla Azevedo; de Oliveira Fernandes, Carlos Augusto; de Almeida, Paulo César; de Sousa Carvalho, Rosimary

    2017-04-01

    This study aimed to analyze which facial, gingival and dental characteristics are associated with confidence in smiling among 75 subjects seeking treatment in a northern Brazilian public dental university. Clinical examinations and three standardized photographs of each subject were taken by one trained examiner. In addition, a questionnaire was applied to assess confidence in smiling. The subjects were dichotomized into two groups, non-confident (n = 36) and confident (n = 39) in smiling. Chi-square/Fischer exact test were used to associate the facial, gingival and dental characteristics between groups. The subjects that reported to be non-confident in smiling were statistically associated with smile type (p = 0.030) and wrongly positioned teeth (p = 0.047). On the other hand, gender (p = 0.491), marital status (p = 0.217), gum pigmentation (p = 0.930), midline (p = 0.176), volume of the upper (p = 0.380), and lower (p = 0.615) lips were not associated with self-reported confidence in smiling. In patients seeking dental treatment in a public dental university, non-confidence in smiling was associated only with some oral and intraoral characteristics and not with demographic characteristics. This study showed that only smile type and wrongly positioned teeth were statistically associated with confidence in smiling. Dentists should pay attention to those intraoral characteristics, but the clinical decision making should always include the patients' perception. (J Esthet Restor Dent 29:E56-E66, 2017). © 2016 Wiley Periodicals, Inc.

  16. Chaos on the interval

    CERN Document Server

    Ruette, Sylvie

    2017-01-01

    The aim of this book is to survey the relations between the various kinds of chaos and related notions for continuous interval maps from a topological point of view. The papers on this topic are numerous and widely scattered in the literature; some of them are little known, difficult to find, or originally published in Russian, Ukrainian, or Chinese. Dynamical systems given by the iteration of a continuous map on an interval have been broadly studied because they are simple but nevertheless exhibit complex behaviors. They also allow numerical simulations, which enabled the discovery of some chaotic phenomena. Moreover, the "most interesting" part of some higher-dimensional systems can be of lower dimension, which allows, in some cases, boiling it down to systems in dimension one. Some of the more recent developments such as distributional chaos, the relation between entropy and Li-Yorke chaos, sequence entropy, and maps with infinitely many branches are presented in book form for the first time. The author gi...

  17. An early Phase II randomised controlled trial testing the effect on persecutory delusions of using CBT to reduce negative cognitions about the self: the potential benefits of enhancing self confidence.

    Science.gov (United States)

    Freeman, Daniel; Pugh, Katherine; Dunn, Graham; Evans, Nicole; Sheaves, Bryony; Waite, Felicity; Cernis, Emma; Lister, Rachel; Fowler, David

    2014-12-01

    Research has shown that paranoia may directly build on negative ideas about the self. Feeling inferior can lead to ideas of vulnerability. The clinical prediction is that decreasing negative self cognitions will reduce paranoia. Thirty patients with persistent persecutory delusions were randomised to receive brief CBT in addition to standard care or to standard care (ISRCTN06118265). The six session intervention was designed to decrease negative, and increase positive, self cognitions. Assessments at baseline, 8 weeks (posttreatment) and 12 weeks were carried out by a rater blind to allocation. The primary outcomes were posttreatment scores for negative self beliefs and paranoia. Secondary outcomes were psychological well-being, positive beliefs about the self, persecutory delusions, social comparison, self-esteem, anxiety, and depression. Trial recruitment and retention were feasible and the intervention highly acceptable to the patients. All patients provided follow-up data. Posttreatment there was a small reduction in negative self beliefs (Cohen's d=0.24) and a moderate reduction in paranoia (d=0.59), but these were not statistically significant. There were statistically significant improvements in psychological well-being (d=1.16), positive beliefs about the self (d=1.00), negative social comparison (d=0.88), self-esteem (d=0.62), and depression (d=0.68). No improvements were maintained. No adverse events were associated with the intervention. The intervention produced short-term gains consistent with the prediction that improving cognitions about the self will reduce persecutory delusions. The improvement in psychological well-being is important in its own right. We recommend that the different elements of the intervention are tested separately and that the treatment is lengthened. Copyright © 2014. Published by Elsevier B.V.

  18. Does Confidence Predict Out-of-Domain Effort?

    NARCIS (Netherlands)

    Prokudina, Elena; Renneboog, Luc; Tobler, Philippe

    2015-01-01

    Predicting worker’s effort is important in many different areas, but is often difficult. Using a laboratory experiment, we test the hypothesis that confidence, i.e. the person-specific beliefs about her abilities, can be used as a generic proxy to predict future effort provision. We measure

  19. Confidence Levels in Statistical Analyses. Analysis of Variances. Case Study.

    Directory of Open Access Journals (Sweden)

    Ileana Brudiu

    2010-05-01

    Full Text Available Applying a statistical test to check statistical assumptions offers a positive or negative response regarding the veracity of the issued hypothesis. In case of variance analysis it’s necessary to apply a post hoc test to determine differences within the group. Statistical estimation using confidence levels provides more information than a statistical test, it shows the high degree of uncertainty resulting from small samples and builds conclusions in terms of "marginally significant" or "almost significant (p being close to 0,05 . The case study shows how the statistical estimation completes the application form the analysis of variance test and Tukey test.

  20. Weighting Mean and Variability during Confidence Judgments

    Science.gov (United States)

    de Gardelle, Vincent; Mamassian, Pascal

    2015-01-01

    Humans can not only perform some visual tasks with great precision, they can also judge how good they are in these tasks. However, it remains unclear how observers produce such metacognitive evaluations, and how these evaluations might be dissociated from the performance in the visual task. Here, we hypothesized that some stimulus variables could affect confidence judgments above and beyond their impact on performance. In a motion categorization task on moving dots, we manipulated the mean and the variance of the motion directions, to obtain a low-mean low-variance condition and a high-mean high-variance condition with matched performances. Critically, in terms of confidence, observers were not indifferent between these two conditions. Observers exhibited marked preferences, which were heterogeneous across individuals, but stable within each observer when assessed one week later. Thus, confidence and performance are dissociable and observers’ confidence judgments put different weights on the stimulus variables that limit performance. PMID:25793275

  1. Interval Female Sterilization.

    Science.gov (United States)

    Stuart, Gretchen S; Ramesh, Shanthi S

    2018-01-01

    Female sterilization is relied on by nearly one in three women aged 35-44 years in the United States. Sterilization procedures are among the most common procedures that obstetrician-gynecologists perform. The most frequent sterilization procedures include postpartum tubal ligation, laparoscopic tubal disruption or salpingectomy, and hysteroscopic tubal occlusion. The informed consent process for sterilization is crucial and requires shared decision-making between the patient and the health care provider. Counseling should include the specific risks and benefits of the specific surgical approaches. Additionally, women should be counseled on the alternatives to sterilization, including intrauterine contraceptives and subdermal contraceptive implants. Complications, including unplanned pregnancy after successful female sterilization, are rare. The objectives of this Clinical Expert Series are to describe the epidemiology of female sterilization, access to postpartum sterilization, advances in interval sterilization techniques, and clinical considerations in caring for women requesting sterilization.

  2. Interpregnancy interval and risk of autistic disorder.

    Science.gov (United States)

    Gunnes, Nina; Surén, Pål; Bresnahan, Michaeline; Hornig, Mady; Lie, Kari Kveim; Lipkin, W Ian; Magnus, Per; Nilsen, Roy Miodini; Reichborn-Kjennerud, Ted; Schjølberg, Synnve; Susser, Ezra Saul; Øyen, Anne-Siri; Stoltenberg, Camilla

    2013-11-01

    A recent California study reported increased risk of autistic disorder in children conceived within a year after the birth of a sibling. We assessed the association between interpregnancy interval and risk of autistic disorder using nationwide registry data on pairs of singleton full siblings born in Norway. We defined interpregnancy interval as the time from birth of the first-born child to conception of the second-born child in a sibship. The outcome of interest was autistic disorder in the second-born child. Analyses were restricted to sibships in which the second-born child was born in 1990-2004. Odds ratios (ORs) were estimated by fitting ordinary logistic models and logistic generalized additive models. The study sample included 223,476 singleton full-sibling pairs. In sibships with interpregnancy intervals autistic disorder, compared with 0.13% in the reference category (≥ 36 months). For interpregnancy intervals shorter than 9 months, the adjusted OR of autistic disorder in the second-born child was 2.18 (95% confidence interval 1.42-3.26). The risk of autistic disorder in the second-born child was also increased for interpregnancy intervals of 9-11 months in the adjusted analysis (OR = 1.71 [95% CI = 1.07-2.64]). Consistent with a previous report from California, interpregnancy intervals shorter than 1 year were associated with increased risk of autistic disorder in the second-born child. A possible explanation is depletion of micronutrients in mothers with closely spaced pregnancies.

  3. Confidence in leadership among the newly qualified.

    Science.gov (United States)

    Bayliss-Pratt, Lisa; Morley, Mary; Bagley, Liz; Alderson, Steven

    2013-10-23

    The Francis report highlighted the importance of strong leadership from health professionals but it is unclear how prepared those who are newly qualified feel to take on a leadership role. We aimed to assess the confidence of newly qualified health professionals working in the West Midlands in the different competencies of the NHS Leadership Framework. Most respondents felt confident in their abilities to demonstrate personal qualities and work with others, but less so at managing or improving services or setting direction.

  4. A crisis of public confidence in vaccines.

    Science.gov (United States)

    Black, Steven; Rappuoli, Rino

    2010-12-08

    A meeting was held in Siena, Italy, in July 2010 to review the evidence for a decrease in public confidence in vaccines, to discuss possible reasons for this phenomenon, and to develop possible strategies to improve public confidence in vaccines. Prevention of morbidity and mortality by vaccination is one of the major public health accomplishments of the last century. Nevertheless, despite the improved safety and effectiveness of vaccines, public confidence in vaccination is decreasing. Improved methods of vaccine safety assessment have not improved public confidence. In addition, dissemination of false information on the Internet has undermined public confidence globally. Reductions in vaccine uptake or use of available vaccines can and have resulted in increased morbidity and mortality due to infectious diseases. The lack of public confidence in vaccines risks undermining the political will necessary to rapidly respond to a more severe influenza pandemic in the future. To improve the current situation, we must define both the risks and the benefits of individual vaccines so that the public can understand the rationale for vaccine recommendations. Key to regaining public trust in vaccines is a credible, consistent, and unified message developed from the private and public sectors that directly addresses public concerns. Unless an active effort is made to improve public confidence and trust in vaccination, there is a risk that gains made in combating the morbidity and mortality of infectious diseases through the use of vaccines will be lost. Loss of political will resulting from this loss of public confidence may also result in inappropriate decisions regarding the development and use of pandemic influenza vaccines for use in future pandemics, thus compromising public health.

  5. Confidence in value-based choice

    Science.gov (United States)

    De Martino, Benedetto; Fleming, Stephen M.; Garrett, Neil; Dolan, Raymond

    2013-01-01

    Summary Decisions are never perfect with confidence in one’s choices fluctuating over time. How subjective confidence and valuation of choice options interact at the level of brain and behavior is unknown. Using a dynamic model of the decision process we show that confidence reflects the evolution of a decision variable over time, explaining the observed relation between confidence, value, accuracy and reaction time. As predicted by our dynamic model, we show that an fMRI signal in human ventromedial prefrontal cortex (vmPFC) reflects both value comparison and confidence in the value comparison process. Crucially, individuals varied in how they related confidence to accuracy, allowing us to show that this introspective ability is predicted by a measure of functional connectivity between vmPFC and rostrolateral prefrontal cortex (rlPFC). Our findings provide a mechanistic link between noise in value comparison and metacognitive awareness of choice, enabling us both to want and to express knowledge of what we want. PMID:23222911

  6. Kangaroo Care Education Effects on Nurses' Knowledge and Skills Confidence.

    Science.gov (United States)

    Almutairi, Wedad Matar; Ludington-Hoe, Susan M

    2016-11-01

    Less than 20% of the 996 NICUs in the United States routinely practice kangaroo care, due in part to the inadequate knowledge and skills confidence of nurses. Continuing education improves knowledge and skills acquisition, but the effects of a kangaroo care certification course on nurses' knowledge and skills confidence are unknown. A pretest-posttest quasi-experiment was conducted. The Kangaroo Care Knowledge and Skills Confidence Tool was administered to 68 RNs at a 2.5-day course about kangaroo care evidence and skills. Measures of central tendency, dispersion, and paired t tests were conducted on 57 questionnaires. The nurses' characteristics were varied. The mean posttest Knowledge score (M = 88.54, SD = 6.13) was significantly higher than the pretest score (M = 78.7, SD = 8.30), t [54] = -9.1, p = .000), as was the posttest Skills Confidence score (pretest M = 32.06, SD = 3.49; posttest M = 26.80, SD = 5.22), t [53] = -8.459, p = .000). The nurses' knowledge and skills confidence of kangaroo care improved following continuing education, suggesting a need for continuing education in this area. J Contin Educ Nurs. 2016;47(11):518-524. Copyright 2016, SLACK Incorporated.

  7. Increasing Product Confidence-Shifting Paradigms.

    Science.gov (United States)

    Phillips, Marla; Kashyap, Vishal; Cheung, Mee-Shew

    2015-01-01

    Leaders in the pharmaceutical, medical device, and food industries expressed a unilateral concern over product confidence throughout the total product lifecycle, an unsettling fact for these leaders to manage given that their products affect the lives of millions of people each year. Fueled by the heparin incident of intentional adulteration in 2008, initial efforts for increasing product confidence were focused on improving the confidence of incoming materials, with a belief that supplier performance must be the root cause. As in the heparin case, concern over supplier performance extended deep into the supply chain to include suppliers of the suppliers-which is often a blind spot for pharmaceutical, device, and food manufacturers. Resolved to address the perceived lack of supplier performance, these U.S. Food and Drug Administration (FDA)-regulated industries began to adopt the supplier relationship management strategy, developed by the automotive industry, that emphasizes "management" of suppliers for the betterment of the manufacturers. Current product and supplier management strategies, however, have not led to a significant improvement in product confidence. As a result of the enduring concern by industry leaders over the lack of product confidence, Xavier University launched the Integrity of Supply Initiative in 2012 with a team of industry leaders and FDA officials. Through a methodical research approach, data generated by the pharmaceutical, medical device, and food manufacturers surprisingly pointed to themselves as a source of the lack of product confidence, and revealed that manufacturers either unknowingly increase the potential for error or can control/prevent many aspects of product confidence failure. It is only through this paradigm shift that manufacturers can work collaboratively with their suppliers as equal partners, instead of viewing their suppliers as "lesser" entities needing to be controlled. The basis of this shift provides manufacturers

  8. Procedural Experience and Confidence Among Graduating Medical Students.

    Science.gov (United States)

    Barr, Justin; Graffeo, Christopher S

    2016-01-01

    Bedside procedures are a vital component of patient care-particularly for surgeons. Anecdotal evidence and previous studies from individual institutions reveal a lack of exposure to these interventions in medical school. Our objective was to ascertain medical students' experience and confidence in performing bedside procedures. Our study included a multi-institutional, anonymous, Health Insurance Portability and Accountability Act-compliant electronic survey. Using a 4-point Likert scale, students were asked how many times they had performed each of 18 common bedside procedures and their anticipated confidence in completing it independently. Statistical analysis included student t test, Chi-square test, analysis of means, linear regression, and Bonferroni correction for multiple comparisons. In total, participants included 2260 4th year medical students at 17 allopathic medical schools. Overall, 644 students replied (28.5% response rate). Most respondents had never placed an arterial line (71%), central venous line (81%), chest tube (89%), intraosseous line (95%), injected a joint (63%), or had performed cardiopulmonary resuscitation (50%), a lumbar puncture (57%), paracentesis (66%), or thoracentesis (92%). Venipuncture, suturing, and Foley catheter placement were the only procedures which greater than 50% of students had performed more than 5 times. Significant correlation was observed (r = 0.7) between experience and confidence, with men being reported significantly higher experience and confidence than women (p < 0.0001). Students entering anesthesia and emergency medicine residencies reported significantly higher experience than those matriculating into other specialties (α = 0.003); students entering emergency medicine and surgery reported significantly higher confidence levels (α = 0.003). The largest survey of its kind, the present study demonstrates that medical students are underexposed to essential bedside procedures and feel uncomfortable performing

  9. ADAM SMITH: THE INVISIBLE HAND OR CONFIDENCE

    Directory of Open Access Journals (Sweden)

    Fernando Luis, Gache

    2010-01-01

    Full Text Available In 1776 Adam Smith raised the matter that an invisible hand was the one which moved the markets to obtain its efficiency. Despite in the present paper we are going to raise the hypothesis, that this invisible hand is in fact the confidence that each person feels when he is going to do business. That in addition it is unique, because it is different from the confidence of the others and that is a variable nonlinear that essentially is ligatured to respective personal histories. For that we are going to take as its bases the paper by Leopoldo Abadía (2009, with respect to the financial economy crisis that happened in 2007-2008, to evidence the form in which confidence operates. Therefore the contribution that we hope to do with this paper is to emphasize that, the level of confidence of the different actors, is the one which really moves the markets, (therefore the economy and that the crisis of the subprime mortgages is a confidence crisis at world-wide level.

  10. Teacher Immediacy, Confidence Testing, and the Measurement of Cognitive Learning

    Science.gov (United States)

    King, Paul; Witt, Paul

    2009-01-01

    There is much disagreement among instructional communication scholars concerning the appropriate means to measure cognitive learning. Significant differences have emerged between studies that rely on perceptual versus performance measures of learning and the issue has been the subject of much recent debate in research on teacher immediacy. The…

  11. Skewness-kurtosis adjusted confidence estimators and significance tests

    National Research Council Canada - National Science Library

    Richter, Wolf-Dieter

    2016-01-01

    .... The orders of convergence to zero of both types of probabilities are assumed to be suitably bounded below according to an Osipov-type condition and the sample distribution is assumed to satisfy...

  12. A systematic review of maternal confidence for physiologic birth: characteristics of prenatal care and confidence measurement.

    Science.gov (United States)

    Avery, Melissa D; Saftner, Melissa A; Larson, Bridget; Weinfurter, Elizabeth V

    2014-01-01

    Because a focus on physiologic labor and birth has reemerged in recent years, care providers have the opportunity in the prenatal period to help women increase confidence in their ability to give birth without unnecessary interventions. However, most research has only examined support for women during labor. The purpose of this systematic review was to examine the research literature for information about prenatal care approaches that increase women's confidence for physiologic labor and birth and tools to measure that confidence. Studies were reviewed that explored any element of a pregnant woman's interaction with her prenatal care provider that helped build confidence in her ability to labor and give birth. Timing of interaction with pregnant women included during pregnancy, labor and birth, and the postpartum period. In addition, we looked for studies that developed a measure of women's confidence related to labor and birth. Outcome measures included confidence or similar concepts, descriptions of components of prenatal care contributing to maternal confidence for birth, and reliability and validity of tools measuring confidence. The search of MEDLINE, CINAHL, PsycINFO, and Scopus databases provided a total of 893 citations. After removing duplicates and articles that did not meet inclusion criteria, 6 articles were included in the review. Three relate to women's confidence for labor during the prenatal period, and 3 describe tools to measure women's confidence for birth. Research about enhancing women's confidence for labor and birth was limited to qualitative studies. Results suggest that women desire information during pregnancy and want to use that information to participate in care decisions in a relationship with a trusted provider. Further research is needed to develop interventions to help midwives and physicians enhance women's confidence in their ability to give birth and to develop a tool to measure confidence for use during prenatal care. © 2014 by

  13. Birth interval and its predictors among married women in Dabat ...

    African Journals Online (AJOL)

    ... their 95% confidence intervals. Median birth interval was 32.6 months (95%CI: 31.2-34.1). The cumulative probabilities of survival at 12, 24, and 36 months were 0.97, 0.82 and 0.56 respectively. Death of the index child (AHR=3.12), contraceptive non use (AHR=4.29) and husband's education (AHR=2.20) were significant ...

  14. Assessing Confidence in Pliocene Sea Surface Temperatures to Evaluate Predictive Models

    Science.gov (United States)

    Dowsett, Harry J.; Robinson, Marci M.; Haywood, Alan M.; Hill, Daniel J.; Dolan, Aisling. M.; Chan, Wing-Le; Abe-Ouchi, Ayako; Chandler, Mark A.; Rosenbloom, Nan A.; Otto-Bliesner, Bette L.; hide

    2012-01-01

    In light of mounting empirical evidence that planetary warming is well underway, the climate research community looks to palaeoclimate research for a ground-truthing measure with which to test the accuracy of future climate simulations. Model experiments that attempt to simulate climates of the past serve to identify both similarities and differences between two climate states and, when compared with simulations run by other models and with geological data, to identify model-specific biases. Uncertainties associated with both the data and the models must be considered in such an exercise. The most recent period of sustained global warmth similar to what is projected for the near future occurred about 3.33.0 million years ago, during the Pliocene epoch. Here, we present Pliocene sea surface temperature data, newly characterized in terms of level of confidence, along with initial experimental results from four climate models. We conclude that, in terms of sea surface temperature, models are in good agreement with estimates of Pliocene sea surface temperature in most regions except the North Atlantic. Our analysis indicates that the discrepancy between the Pliocene proxy data and model simulations in the mid-latitudes of the North Atlantic, where models underestimate warming shown by our highest-confidence data, may provide a new perspective and insight into the predictive abilities of these models in simulating a past warm interval in Earth history.This is important because the Pliocene has a number of parallels to present predictions of late twenty-first century climate.

  15. A confidence set inference procedure for gene mapping using markers with incomplete polymorphism.

    Science.gov (United States)

    Papachristou, Charalampos; Lin, Shili

    2005-01-01

    A recent approach for gene mapping based on confidence set inference (CSI) promises several advantages, including avoidance of corrections for multiple tests, availability of confidence intervals with known statistical properties, and sufficient localizations of disease genes. This paper proposes an extended CSI procedure that can handle markers with incomplete polymorphism, thereby increasing the applicability of the set of CSI methods in practical situations. Simulation studies show that the new procedure retains the main advantages of the original CSI. Although it generally requires more data to achieve a similar power, this increase is moderate for markers with 80% heterozygosity or higher. We also investigate the effects of relative risk estimates and disease models. Our analyses show that perturbation from actual relative risks or multilocus disease models generally leads to reduction in power or inflation in type I error, as expected. Nevertheless, for certain classes of two-locus disease models, CSI can still perform well, with reasonably high actual coverage probabilities for at least one of the disease loci. Application of CSI to the data provided by the Genetic Analysis Workshop 13 yields encouraging results, as they compare favorably to those obtained from GENEHUNTER using its NPL sib-pair method. Copyright 2005 S. Karger AG, Basel.

  16. Optimal Wind Power Uncertainty Intervals for Electricity Market Operation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ying; Zhou, Zhi; Botterud, Audun; Zhang, Kaifeng

    2018-01-01

    It is important to select an appropriate uncertainty level of the wind power forecast for power system scheduling and electricity market operation. Traditional methods hedge against a predefined level of wind power uncertainty, such as a specific confidence interval or uncertainty set, which leaves the questions of how to best select the appropriate uncertainty levels. To bridge this gap, this paper proposes a model to optimize the forecast uncertainty intervals of wind power for power system scheduling problems, with the aim of achieving the best trade-off between economics and reliability. Then we reformulate and linearize the models into a mixed integer linear programming (MILP) without strong assumptions on the shape of the probability distribution. In order to invest the impacts on cost, reliability, and prices in a electricity market, we apply the proposed model on a twosettlement electricity market based on a six-bus test system and on a power system representing the U.S. state of Illinois. The results show that the proposed method can not only help to balance the economics and reliability of the power system scheduling, but also help to stabilize the energy prices in electricity market operation.

  17. Diagnosing dementia with confidence by GPs.

    NARCIS (Netherlands)

    Hout, H.P.J. van; Vernooij-Dassen, M.J.F.J.; Stalman, W.A.B.

    2007-01-01

    BACKGROUND: Earlier reports suggest limited clinical reasoning and substantial uncertainty of GPs in assessing patients suspected of dementia. OBJECTIVE: To explore the predictors of GPs to decide on the presence and absence of dementia as well as the predictors of diagnostic confidence of GPs.

  18. Observed Consultation: Confidence and Accuracy of Assessors

    Science.gov (United States)

    Tweed, Mike; Ingham, Christopher

    2010-01-01

    Judgments made by the assessors observing consultations are widely used in the assessment of medical students. The aim of this research was to study judgment accuracy and confidence and the relationship between these. Assessors watched recordings of consultations, scoring the students on: a checklist of items; attributes of consultation; a…

  19. The confidence effects of fiscal consolidations

    NARCIS (Netherlands)

    Beetsma, R.M.W.J.; Cimadomo, J.; Furtuna, O.; Giuliodori, M.

    2014-01-01

    We explore how fiscal consolidations affect private sector confidence, a possible channel for the fiscal transmission that has received particular attention recently as a result of governments embarking on austerity trajectories in the aftermath of the crisis. Panel regressions based on the

  20. The confidence effects of fiscal consolidations

    NARCIS (Netherlands)

    Beetsma, R.; Cimadomo, J.; Furtuna, O.; Giuliodori, M.

    2015-01-01

    We explore how fiscal consolidations affect private sector confidence, a possible channel for the transmission of fiscal policy that has received particular attention recently as a result of governments embarking on austerity trajectories in the aftermath of the crisis. Panel regressions based on

  1. Growing confidence, building skills | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Ahmed K. Rashid. Research Awards. 2014. @ahkrashid. For two-time Research Award recipient (2012 and 2014) Ahmed Rashid, his IDRC experience “gave me the confidence to conduct high quality research in social sciences.” In 2012 Rashid explored the influence of think tanks on policy in Bangladesh, as well as their ...

  2. A Confidence Paradigm for Classification Systems

    Science.gov (United States)

    2008-09-01

    some of the overall vocabulary of ATR as well as an object-taxonomy. Fenton and Wang [20] state that classical multi-criteria decision making ( MCDM ...paper intro- duces general fuzzy MCDM problem. The authors state that they believe risk and confidence are the two dimensions in which the DM’s

  3. Detecting Disease in Radiographs with Intuitive Confidence

    Directory of Open Access Journals (Sweden)

    Stefan Jaeger

    2015-01-01

    Full Text Available This paper argues in favor of a specific type of confidence for use in computer-aided diagnosis and disease classification, namely, sine/cosine values of angles represented by points on the unit circle. The paper shows how this confidence is motivated by Chinese medicine and how sine/cosine values are directly related with the two forces Yin and Yang. The angle for which sine and cosine are equal (45° represents the state of equilibrium between Yin and Yang, which is a state of nonduality that indicates neither normality nor abnormality in terms of disease classification. The paper claims that the proposed confidence is intuitive and can be readily understood by physicians. The paper underpins this thesis with theoretical results in neural signal processing, stating that a sine/cosine relationship between the actual input signal and the perceived (learned input is key to neural learning processes. As a practical example, the paper shows how to use the proposed confidence values to highlight manifestations of tuberculosis in frontal chest X-rays.

  4. Confidence building in emerging stock markets

    NARCIS (Netherlands)

    Perotti, E.C.; Laeven, L.; van Oijen, P.

    2000-01-01

    Investor confidence in reliable property rights and stable, market-oriented policies are a necessary condition for financial integration and the development of emerging stock markets. Announced market-oriented policies may be reversed, however, and are initially not fully credible. We argue that

  5. Confidence building in emerging stock markets

    NARCIS (Netherlands)

    Laeven, L.; Perotti, E.C.

    2001-01-01

    Investor confidence in reliable property rights and stable, market-oriented policies are a necessary condition for financial integration and the development of emerging stock markets. Announced market-oriented policies may be reversed, however, and are initially not fully credible. We argue that

  6. Sparse Multidimensional Patient Modeling using Auxiliary Confidence Labels.

    Science.gov (United States)

    Heim, Eric; Hauskrecht, Milos

    2015-11-01

    In this work, we focus on the problem of learning a classification model that performs inference on patient Electronic Health Records (EHRs). Often, a large amount of costly expert supervision is required to learn such a model. To reduce this cost, we obtain confidence labels that indicate how sure an expert is in the class labels she provides. If meaningful confidence information can be incorporated into a learning method, fewer patient instances may need to be labeled to learn an accurate model. In addition, while accuracy of predictions is important for any inference model, a model of patients must be interpretable so that clinicians can understand how the model is making decisions. To these ends, we develop a novel metric learning method called Confidence bAsed MEtric Learning (CAMEL) that supports inclusion of confidence labels, but also emphasizes interpretability in three ways. First, our method induces sparsity, thus producing simple models that use only a few features from patient EHRs. Second, CAMEL naturally produces confidence scores that can be taken into consideration when clinicians make treatment decisions. Third, the metrics learned by CAMEL induce multidimensional spaces where each dimension represents a different "factor" that clinicians can use to assess patients. In our experimental evaluation, we show on a real-world clinical data set that our CAMEL methods are able to learn models that are as or more accurate as other methods that use the same supervision. Furthermore, we show that when CAMEL uses confidence scores it is able to learn models as or more accurate as others we tested while using only 10% of the training instances. Finally, we perform qualitative assessments on the metrics learned by CAMEL and show that they identify and clearly articulate important factors in how the model performs inference.

  7. Association Between a Prolonged PR Interval and Outcomes of Cardiac Resynchronization Therapy: A Report From the National Cardiovascular Data Registry.

    Science.gov (United States)

    Friedman, Daniel J; Bao, Haikun; Spatz, Erica S; Curtis, Jeptha P; Daubert, James P; Al-Khatib, Sana M

    2016-11-22

    A prolonged PR interval is common among cardiac resynchronization therapy (CRT) candidates; however, the association between PR interval and outcomes is unclear, and the data are conflicting. We conducted inverse probability weighted analyses of 26 451 CRT-eligible (ejection fraction ≤35, QRS ≥120 ms) patients from the National Cardiovascular Data Registry ICD Registry to assess the association between a prolonged PR interval (≥230 ms), receipt of CRT with defibrillator (CRT-D) versus implantable cardioverter defibrillator (ICD), and outcomes. We first tested the association between a prolonged PR interval and outcomes among patients stratified by device type. Next, we performed a comparative effectiveness analysis of CRT-D versus ICD among patients when stratified by PR interval. Using Medicare claims data, we followed up with patients up to 5 years for incident heart failure hospitalization or death. Patients with a PR≥230 ms (15%; n=4035) were older and had more comorbidities, including coronary artery disease, atrial arrhythmias, diabetes mellitus, and chronic kidney disease. After risk adjustment, a PR≥230 ms (versus PR<230 ms) was associated with increased risk of heart failure hospitalization or death among CRT-D (hazard ratio, 1.23; 95% confidence interval, 1.14-1.31; P<0.001) but not ICD recipients (hazard ratio, 1.08; 95% confidence interval, 0.97-1.20; P=0.17) (Pinteraction=0.043). CRT-D (versus ICD) was associated with lower rates of heart failure hospitalization or death among patients with PR<230 ms (hazard ratio, 0.79; 95% confidence interval, 0.73-0.85; P<0.001) but not PR≥230 ms (hazard ratio, 1.01; 95% confidence interval, 0.87-1.17; P=0.90) (Pinteraction=0.0025). A PR≥230 ms is associated with increased rates of heart failure hospitalization or death among CRT-D patients. The real-world comparative effectiveness of CRT-D (versus ICD) is significantly less among patients with a PR≥230 ms in comparison with patients with a PR<230

  8. A Gompertz model for birth interval analysis.

    Science.gov (United States)

    Ross, J A; MAdhavan, Shantha

    1981-11-01

    During recent years birth intervals have been analysed on a life table basis. This method retains both closed and open intervals, and so reflects behaviour that deliberately avoids the next birth entirely. When life tables are prepared separately for each birth order, markedly different patterns of movement toward the next birth can appear from one parity to the next. This is illustrated for Korean survey data, with historical trends given across marriage cohorts. A Gompertz model is found to fit the family of curves that show the cumulative proportion giving birth within each interval closely. Its three parameters have direct intuitive interpretations, one being equal to the parity progression ratio and the other two controlling the pace of childbearing before and after the point of peak activity within the interval. The model is useful for interpolation and projection, and provides an efficient summary of the otherwise cumbersome detail given in a life table. Testing against additional data sets is suggested.

  9. Building Public Confidence in Nuclear Activities

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, T

    2002-03-27

    Achieving public acceptance has become a central issue in discussions regarding the future of nuclear power and associated nuclear activities. Effective public communication and public participation are often put forward as the key building blocks in garnering public acceptance. A recent international workshop in Finland provided insights into other features that might also be important to building and sustaining public confidence in nuclear activities. The workshop was held in Finland in close cooperation with Finnish stakeholders. This was most appropriate because of the recent successes in achieving positive decisions at the municipal, governmental, and Parliamentary levels, allowing the Finnish high-level radioactive waste repository program to proceed, including the identification and approval of a proposed candidate repository site. Much of the workshop discussion appropriately focused on the roles of public participation and public communications in building public confidence. It was clear that well constructed and implemented programs of public involvement and communication and a sense of fairness were essential in building the extent of public confidence needed to allow the repository program in Finland to proceed. It was also clear that there were a number of other elements beyond public involvement that contributed substantially to the success in Finland to date. And, in fact, it appeared that these other factors were also necessary to achieving the Finnish public acceptance. In other words, successful public participation and communication were necessary but not sufficient. What else was important? Culture, politics, and history vary from country to country, providing differing contexts for establishing and maintaining public confidence. What works in one country will not necessarily be effective in another. Nonetheless, there appear to be certain elements that might be common to programs that are successful in sustaining public confidence and some of

  10. Building Public Confidence in Nuclear Activities

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, T

    2002-02-13

    Achieving public acceptance has become a central issue in discussions regarding the future of nuclear power and associated nuclear activities. Effective public communication and public participation are often put forward as the key building blocks in garnering public acceptance. A recent international workshop in Finland provided insights into other features that might also be important to building and sustaining public confidence in nuclear activities. The workshop was held in Finland in close cooperation with Finnish stakeholders. This was most appropriate because of the recent successes in achieving positive decisions at the municipal, governmental, and Parliamentary levels, allowing the Finnish high-level radioactive waste repository program to proceed, including the identification and approval of a proposed candidate repository site Much of the workshop discussion appropriately focused on the roles of public participation and public communications in building public confidence. It was clear that well constructed and implemented programs of public involvement and communication and a sense of fairness were essential in building the extent of public confidence needed to allow the repository program in Finland to proceed. It was also clear that there were a number of other elements beyond public involvement that contributed substantially to the success in Finland to date. And, in fact, it appeared that these other factors were also necessary to achieving the Finnish public acceptance. In other words, successful public participation and communication were necessary but not sufficient. What else was important? Culture, politics, and history vary from country to country, providing differing contexts for establishing and maintaining public confidence. What works in one country will not necessarily be effective in another. Nonetheless, there appear to be certain elements that might be common to programs that are successful in sustaining public confidence, and some of

  11. Fast transfer of crossmodal time interval training.

    Science.gov (United States)

    Chen, Lihan; Zhou, Xiaolin

    2014-06-01

    Sub-second time perception is essential for many important sensory and perceptual tasks including speech perception, motion perception, motor coordination, and crossmodal interaction. This study investigates to what extent the ability to discriminate sub-second time intervals acquired in one sensory modality can be transferred to another modality. To this end, we used perceptual classification of visual Ternus display (Ternus in Psychol Forsch 7:81-136, 1926) to implicitly measure participants' interval perception in pre- and posttests and implemented an intra- or crossmodal sub-second interval discrimination training protocol in between the tests. The Ternus display elicited either an "element motion" or a "group motion" percept, depending on the inter-stimulus interval between the two visual frames. The training protocol required participants to explicitly compare the interval length between a pair of visual, auditory, or tactile stimuli with a standard interval or to implicitly perceive the length of visual, auditory, or tactile intervals by completing a non-temporal task (discrimination of auditory pitch or tactile intensity). Results showed that after fast explicit training of interval discrimination (about 15 min), participants improved their ability to categorize the visual apparent motion in Ternus displays, although the training benefits were mild for visual timing training. However, the benefits were absent for implicit interval training protocols. This finding suggests that the timing ability in one modality can be rapidly acquired and used to improve timing-related performance in another modality and that there may exist a central clock for sub-second temporal processing, although modality-specific perceptual properties may constrain the functioning of this clock.

  12. Dynamic classification using credible intervals in longitudinal discriminant analysis.

    Science.gov (United States)

    Hughes, David M; Komárek, Arnošt; Bonnett, Laura J; Czanner, Gabriela; García-Fiñana, Marta

    2017-10-30

    Recently developed methods of longitudinal discriminant analysis allow for classification of subjects into prespecified prognostic groups using longitudinal history of both continuous and discrete biomarkers. The classification uses Bayesian estimates of the group membership probabilities for each prognostic group. These estimates are derived from a multivariate generalised linear mixed model of the biomarker's longitudinal evolution in each of the groups and can be updated each time new data is available for a patient, providing a dynamic (over time) allocation scheme. However, the precision of the estimated group probabilities differs for each patient and also over time. This precision can be assessed by looking at credible intervals for the group membership probabilities. In this paper, we propose a new allocation rule that incorporates credible intervals for use in context of a dynamic longitudinal discriminant analysis and show that this can decrease the number of false positives in a prognostic test, improving the positive predictive value. We also establish that by leaving some patients unclassified for a certain period, the classification accuracy of those patients who are classified can be improved, giving increased confidence to clinicians in their decision making. Finally, we show that determining a stopping rule dynamically can be more accurate than specifying a set time point at which to decide on a patient's status. We illustrate our methodology using data from patients with epilepsy and show how patients who fail to achieve adequate seizure control are more accurately identified using credible intervals compared to existing methods. © 2017 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  13. The effect of terrorism on public confidence : an exploratory study.

    Energy Technology Data Exchange (ETDEWEB)

    Berry, M. S.; Baldwin, T. E.; Samsa, M. E.; Ramaprasad, A.; Decision and Information Sciences

    2008-10-31

    A primary goal of terrorism is to instill a sense of fear and vulnerability in a population and to erode confidence in government and law enforcement agencies to protect citizens against future attacks. In recognition of its importance, the Department of Homeland Security includes public confidence as one of the metrics it uses to assess the consequences of terrorist attacks. Hence, several factors--including a detailed understanding of the variations in public confidence among individuals, by type of terrorist event, and as a function of time--are critical to developing this metric. In this exploratory study, a questionnaire was designed, tested, and administered to small groups of individuals to measure public confidence in the ability of federal, state, and local governments and their public safety agencies to prevent acts of terrorism. Data were collected from the groups before and after they watched mock television news broadcasts portraying a smallpox attack, a series of suicide bomber attacks, a refinery bombing, and cyber intrusions on financial institutions that resulted in identity theft and financial losses. Our findings include the following: (a) the subjects can be classified into at least three distinct groups on the basis of their baseline outlook--optimistic, pessimistic, and unaffected; (b) the subjects make discriminations in their interpretations of an event on the basis of the nature of a terrorist attack, the time horizon, and its impact; (c) the recovery of confidence after a terrorist event has an incubation period and typically does not return to its initial level in the long-term; (d) the patterns of recovery of confidence differ between the optimists and the pessimists; and (e) individuals are able to associate a monetary value with a loss or gain in confidence, and the value associated with a loss is greater than the value associated with a gain. These findings illustrate the importance the public places in their confidence in government

  14. Measuring the Confidence of 8th Grade Taiwanese Students' Knowledge of Acids and Bases

    Science.gov (United States)

    Jack, Brady Michael; Liu, Chia-Ju; Chiu, Houn-Lin; Tsai, Chun-Yen

    2012-01-01

    The present study investigated whether gender differences were present on the confidence judgments made by 8th grade Taiwanese students on the accuracy of their responses to acid-base test items. A total of 147 (76 male, 71 female) students provided item-specific confidence judgments during a test of their knowledge of acids and bases. Using the…

  15. The Effect of Adaptive Confidence Strategies in Computer-Assisted Instruction on Learning and Learner Confidence

    Science.gov (United States)

    Warren, Richard Daniel

    2012-01-01

    The purpose of this research was to investigate the effects of including adaptive confidence strategies in instructionally sound computer-assisted instruction (CAI) on learning and learner confidence. Seventy-one general educational development (GED) learners recruited from various GED learning centers at community colleges in the southeast United…

  16. Comment and Completion: Implementation of Parallelism Testing for Four-Parameter Logistic Model in Bioassays.

    Science.gov (United States)

    Sondag, Perceval; Joie, Raphael; Yang, Harry

    2015-01-01

    Parallelism testing between two four-parameter logistic curves has been widely discussed over the last decade. Current tests available in common statistical software used in laboratories have been shown to be highly flawed. In 2012, Yang et al. showed an easy way to implement an intersection union test based on confidence intervals on ratios of parameters of both curves. The method was automated using a fully good manufacturing practice-compliant software package. Although the rationale is correct and efficient, a small mistake appears in the computation of the confidence intervals in the paper and may lead to error when implementing the intersection union test in a software package. Because parallelism testing is both a prerequisite for the determination of relative potency of bioassays and a regulatory requirement, it is important to rectify this mistake. In this paper, we show the actual formulas to be used to compute confidence interval on ratios of parameters. © PDA, Inc. 2015.

  17. The cerebellum's contribution to beat interval discrimination.

    Science.gov (United States)

    Paquette, S; Fujii, S; Li, H C; Schlaug, G

    2017-12-01

    From expert percussionists to individuals who cannot dance, there are widespread differences in people's abilities to perceive and synchronize with a musical beat. The aim of our study was to identify candidate brain regions that might be associated with these abilities. For this purpose, we used Voxel-Based-Morphometry to correlate inter-individual differences in performance on the Harvard Beat Assessment Tests (H-BAT) with local inter-individual variations in gray matter volumes across the entire brain space in 60 individuals. Analysis revealed significant co-variations between performances on two perceptual tasks of the Harvard Beat Assessment Tests associated with beat interval change discrimination (faster, slower) and gray matter volume variations in the cerebellum. Participant discrimination thresholds for the Beat Finding Interval Test (quarter note beat) were positively associated with gray matter volume variation in cerebellum lobule IX in the left hemisphere and crus I bilaterally. Discrimination thresholds for the Beat Interval Test (simple series of tones) revealed the tendency for a positive association with gray matter volume variations in crus I/II of the left cerebellum. Our results demonstrate the importance of the cerebellum in beat interval discrimination skills, as measured by two perceptual tasks of the Harvard Beat Assessment Tests. Current findings, in combination with evidence from patients with cerebellar degeneration and expert dancers, suggest that cerebellar gray matter and overall cerebellar integrity are important for temporal discrimination abilities. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Effects of parental divorce on marital commitment and confidence.

    Science.gov (United States)

    Whitton, Sarah W; Rhoades, Galena K; Stanley, Scott M; Markman, Howard J

    2008-10-01

    Research on the intergenerational transmission of divorce has demonstrated that compared with offspring of nondivorced parents, those of divorced parents generally have more negative attitudes toward marriage as an institution and are less optimistic about the feasibility of a long-lasting, healthy marriage. It is also possible that when entering marriage themselves, adults whose parents divorced have less personal relationship commitment to their own marriages and less confidence in their own ability to maintain a happy marriage with their spouse. However, this prediction has not been tested. In the current study, we assessed relationship commitment and relationship confidence, as well as parental divorce and retrospectively reported interparental conflict, in a sample of 265 engaged couples prior to their first marriage. Results demonstrated that women's, but not men's, parental divorce was associated with lower relationship commitment and lower relationship confidence. These effects persisted when controlling for the influence of recalled interparental conflict and premarital relationship adjustment. The current findings suggest that women whose parents divorced are more likely to enter marriage with relatively lower commitment to, and confidence in, the future of those marriages, potentially raising their risk for divorce. Copyright 2008 APA, all rights reserved.

  19. Effects of Parental Divorce on Marital Commitment and Confidence

    Science.gov (United States)

    Whitton, Sarah W.; Rhoades, Galena K.; Stanley, Scott M.; Markman, Howard J.

    2009-01-01

    Research on the intergenerational transmission of divorce has demonstrated that, compared to offspring of non-divorced parents, those of divorced parents generally have more negative attitudes towards marriage as an institution and are less optimistic about the feasibility of a long-lasting, healthy marriage. It is also possible that, when entering marriage themselves, adults whose parents divorced have less personal relationship commitment to their own marriages and less confidence in their own ability to maintain a happy marriage with their spouse. However, this prediction has not been tested. In the current study, we assessed relationship commitment and relationship confidence, as well as parental divorce and retrospectively-reported interparental conflict, in a sample of 265 engaged couples prior to their first marriage. Results demonstrated that women’s but not men’s parental divorce was associated with lower relationship commitment and lower relationship confidence. These effects persisted when controlling for the influence of recalled interparental conflict and premarital relationship adjustment. The current findings suggest that women whose parents divorced are more likely to enter marriage with relatively lower commitment to, and confidence in, the future of those marriages, potentially raising their risk for divorce. PMID:18855515

  20. Examining multidimensional sport-confidence in athletes and non-athlete sport performers.

    Science.gov (United States)

    Machida, Moe; Otten, Mark; Magyar, T Michelle; Vealey, Robin S; Ward, Rose Marie

    2017-03-01

    Sport-confidence is considered a critical success factor for sport performers at all levels. Researchers have suggested that sport-confidence is a multidimensional rather than a unidimensional construct, and the sport-confidence model identified three types of sport-confidence (i.e., physical skills and training, cognitive efficiency, and resilience) that are important for success in sport. However, such multidimensionality of sport-confidence and its measurement have not been fully examined. On a large sample of sport performers with varied skill levels and characteristics, the purpose of the present study was to examine the three-factor model of sport-confidence. We tested the measurement invariance of the Sport-Confidence Inventory across 512 athletes and 1170 non-athlete sport performers. Results from the multiple group model analysis showed that the three-factor model of sport-confidence fit better for the athlete sample than for the non-athlete sample. The results implicate that the three-factor model of sport-confidence model is suitable to athletes, though sport-confidence may appear more unidimensional for non-athletes. The use of the Sport-Confidence Inventory for non-athlete sport performers demands further consideration; however, the findings implicate that it could be a useful tool to assess sport-confidence of sport performers at any levels.

  1. Graphical interpretation of confidence curves in rankit plots

    DEFF Research Database (Denmark)

    Hyltoft Petersen, Per; Blaabjerg, Ole; Andersen, Marianne

    2004-01-01

    A well-known transformation from the bell-shaped Gaussian (normal) curve to a straight line in the rankit plot is investigated, and a tool for evaluation of the distribution of reference groups is presented. It is based on the confidence intervals for percentiles of the calculated Gaussian...... distribution and the percentage of cumulative points exceeding these limits. The process is to rank the reference values and plot the cumulative frequency points in a rankit plot with a logarithmic (In=log(e)) transformed abscissa. If the distribution is close to In-Gaussian the cumulative frequency points...... presentation, however, makes it easy to disclose deviations from In-Gaussianity, and to make other interpretations of the distributions, e.g., comparison to non-Gaussian distributions in the same plot, where the cumulative frequency percentage can be read from the ordinate. A long list of examples of In...

  2. Confidence leak in perceptual decision-making

    Science.gov (United States)

    Rahnev, Dobromir; Koizumi, Ai; McCurdy, Li Yan; D’Esposito, Mark; Lau, Hakwan

    2015-01-01

    We live in a continuous environment in which the visual scene changes on a slow timescale. It has been shown that, to exploit such environmental stability, the brain creates a “continuity field” such that objects seen seconds ago influence the perception of current objects. What is unknown is whether a similar mechanism exists at the level of our metacognitive representations. In three experiments we demonstrate a robust inter-task “confidence leak” that cannot be explained by response priming or attentional fluctuations. Observers’ ability to modulate this confidence leak predicted higher capacity for metacognition as well as greater gray matter volume in the prefrontal cortex. A model based on normative principles from Bayesian inference explained the results by postulating that observers subjectively estimate the perceptual signal strength in a stable environment. These results point to the existence of a novel metacognitive mechanism mediated by regions in prefrontal cortex. PMID:26408037

  3. ;Agreement; in the IPCC Confidence measure

    Science.gov (United States)

    Rehg, William; Staley, Kent

    2017-02-01

    The Intergovernmental Panel on Climate Change (IPCC) has, in its most recent Assessment Report (AR5), articulated guidelines for evaluating and communicating uncertainty that include a qualitative scale of confidence. We examine one factor included in that scale: the "degree of agreement." Some discussions of the degree of agreement in AR5 suggest that the IPCC is employing a consensus-oriented social epistemology. We consider the application of the degree of agreement factor in practice in AR5. Our findings, though based on a limited examination, suggest that agreement attributions do not so much track the overall consensus among investigators as the degree to which relevant research findings substantively converge in offering support for IPCC claims. We articulate a principle guiding confidence attributions in AR5 that centers not on consensus but on the notion of support. In concluding, we tentatively suggest a pluralist approach to the notion of support.

  4. Social media sentiment and consumer confidence

    OpenAIRE

    Piet J.H. Daas; Puts, Marco J.H.

    2014-01-01

    Changes in the sentiment of Dutch public social media messages were compared with changes in monthly consumer confidence over a period of three-and-a-half years, revealing that both were highly correlated (up to r = 0.9) and that both series cointegrated. This phenomenon is predominantly affected by changes in the sentiment of all Dutch public Facebook messages. The inclusion of various selections of public Twitter messages improved this association and the response to changes in sentiment. G...

  5. Measuring Bubble Expectations and Investor Confidence

    OpenAIRE

    Robert J. Shiller

    1999-01-01

    This paper presents evidence on attitude changes among investors in the US stock market. Two basic attitudes are explored: bubble expectations and investor confidence. Semiannual time-series indicators of these attitudes are presented for US stock market institutional investors based on questionnaire survey results 1989 1998, from surveys that I have derived in collaboration with Fumiko Kon-Ya and Yoshiro Tsutsui. Five different time-series indicators of whether there is among investors an ex...

  6. Ambulatory Function and Perception of Confidence in Persons with Stroke with a Custom-Made Hinged versus a Standard Ankle Foot Orthosis

    Directory of Open Access Journals (Sweden)

    Angélique Slijper

    2012-01-01

    Full Text Available Objective. The aim was to compare walking with an individually designed dynamic hinged ankle foot orthosis (DAFO and a standard carbon composite ankle foot orthosis (C-AFO. Methods. Twelve participants, mean age 56 years (range 26–72, with hemiparesis due to stroke were included in the study. During the six-minute walk test (6MW, walking velocity, the Physiological Cost Index (PCI, and the degree of experienced exertion were measured with a DAFO and C-AFO, respectively, followed by a Stairs Test velocity and perceived confidence was rated. Results. The mean differences in favor for the DAFO were in 6MW 24.3 m (95% confidence interval [CI] 4.90, 43.76, PCI −0.09 beats/m (95% CI −0.27, 0.95, velocity 0.04 m/s (95% CI −0.01, 0.097, and in the Stairs Test −11.8 s (95% CI −19.05, −4.48. All participants except one perceived the degree of experienced exertion lower and felt more confident when walking with the DAFO. Conclusions. Wearing a DAFO resulted in longer walking distance and faster stair climbing compared to walking with a C-AFO. Eleven of twelve participants felt more confident with the DAFO, which may be more important than speed and distance and the most important reason for prescribing an AFO.

  7. Ambulatory Function and Perception of Confidence in Persons with Stroke with a Custom-Made Hinged versus a Standard Ankle Foot Orthosis.

    Science.gov (United States)

    Slijper, Angélique; Danielsson, Anna; Willén, Carin

    2012-01-01

    Objective. The aim was to compare walking with an individually designed dynamic hinged ankle foot orthosis (DAFO) and a standard carbon composite ankle foot orthosis (C-AFO). Methods. Twelve participants, mean age 56 years (range 26-72), with hemiparesis due to stroke were included in the study. During the six-minute walk test (6MW), walking velocity, the Physiological Cost Index (PCI), and the degree of experienced exertion were measured with a DAFO and C-AFO, respectively, followed by a Stairs Test velocity and perceived confidence was rated. Results. The mean differences in favor for the DAFO were in 6MW 24.3 m (95% confidence interval [CI] 4.90, 43.76), PCI -0.09 beats/m (95% CI -0.27, 0.95), velocity 0.04 m/s (95% CI -0.01, 0.097), and in the Stairs Test -11.8 s (95% CI -19.05, -4.48). All participants except one perceived the degree of experienced exertion lower and felt more confident when walking with the DAFO. Conclusions. Wearing a DAFO resulted in longer walking distance and faster stair climbing compared to walking with a C-AFO. Eleven of twelve participants felt more confident with the DAFO, which may be more important than speed and distance and the most important reason for prescribing an AFO.

  8. Prediction and tolerance intervals for dynamic treatment regimes.

    Science.gov (United States)

    Lizotte, Daniel J; Tahmasebi, Arezoo

    2017-08-01

    We develop and evaluate tolerance interval methods for dynamic treatment regimes (DTRs) that can provide more detailed prognostic information to patients who will follow an estimated optimal regime. Although the problem of constructing confidence intervals for DTRs has been extensively studied, prediction and tolerance intervals have received little attention. We begin by reviewing in detail different interval estimation and prediction methods and then adapting them to the DTR setting. We illustrate some of the challenges associated with tolerance interval estimation stemming from the fact that we do not typically have data that were generated from the estimated optimal regime. We give an extensive empirical evaluation of the methods and discussed several practical aspects of method choice, and we present an example application using data from a clinical trial. Finally, we discuss future directions within this important emerging area of DTR research.

  9. Recurrence interval analysis of trading volumes.

    Science.gov (United States)

    Ren, Fei; Zhou, Wei-Xing

    2010-06-01

    We study the statistical properties of the recurrence intervals τ between successive trading volumes exceeding a certain threshold q. The recurrence interval analysis is carried out for the 20 liquid Chinese stocks covering a period from January 2000 to May 2009, and two Chinese indices from January 2003 to April 2009. Similar to the recurrence interval distribution of the price returns, the tail of the recurrence interval distribution of the trading volumes follows a power-law scaling, and the results are verified by the goodness-of-fit tests using the Kolmogorov-Smirnov (KS) statistic, the weighted KS statistic and the Cramér-von Mises criterion. The measurements of the conditional probability distribution and the detrended fluctuation function show that both short-term and long-term memory effects exist in the recurrence intervals between trading volumes. We further study the relationship between trading volumes and price returns based on the recurrence interval analysis method. It is found that large trading volumes are more likely to occur following large price returns, and the comovement between trading volumes and price returns is more pronounced for large trading volumes.

  10. Simultaneous confidence bands for nonlinear regression models with application to population pharmacokinetic analyses.

    Science.gov (United States)

    Gsteiger, S; Bretz, F; Liu, W

    2011-07-01

    Many applications in biostatistics rely on nonlinear regression models, such as, for example, population pharmacokinetic and pharmacodynamic modeling, or modeling approaches for dose-response characterization and dose selection. Such models are often expressed as nonlinear mixed-effects models, which are implemented in all major statistical software packages. Inference on the model curve can be based on the estimated parameters, from which pointwise confidence intervals for the mean profile at any single point in the covariate region (time, dose, etc.) can be derived. These pointwise confidence intervals, however, should not be used for simultaneous inferences beyond that single covariate value. If assessment over the entire covariate region is required, the joint coverage probability by using the combined pointwise confidence intervals is likely to be less than the nominal coverage probability. In this paper we consider simultaneous confidence bands for the mean profile over the covariate region of interest and propose two large-sample methods for their construction. The first method is based on the Schwarz inequality and an asymptotic χ(2) distribution. The second method relies on simulating from a multivariate normal distribution. We illustrate the methods with the pharmacokinetics of theophylline. In addition, we report the results of an extensive simulation study to investigate the operating characteristics of the two construction methods. Finally, we present extensions to construct simultaneous confidence bands for the difference of two models and to assess equivalence between two models in biosimilarity applications.

  11. Interval Entropy and Informative Distance

    Directory of Open Access Journals (Sweden)

    Fakhroddin Misagh

    2012-03-01

    Full Text Available The Shannon interval entropy function as a useful dynamic measure of uncertainty for two sided truncated random variables has been proposed in the literature of reliability. In this paper, we show that interval entropy can uniquely determine the distribution function. Furthermore, we propose a measure of discrepancy between two lifetime distributions at the interval of time in base of Kullback-Leibler discrimination information. We study various properties of this measure, including its connection with residual and past measures of discrepancy and interval entropy, and we obtain its upper and lower bounds.

  12. The Calculation and Use of Confidence Bounds in POD Models

    Science.gov (United States)

    Spencer, Floyd W.

    2007-03-01

    At a qualitative level the calculation of a statistical confidence interval for a quantity X is an attempt to answer the question: "How variable could X have been and still be consistent with the data that have been observed?" Models used in POD estimation fit an entire curve to the data in hand. However, the quantity of interest, X(p), is often a single point on the curve, such as the flaw size for which the probability of detection is equal to p. In order to make a confidence statement about X(p) the uncertainty about the parameter estimates are translated to the uncertainty about X(p). Often the calculation is made for each p and the results displayed as a curve. Curves derived in such a manner are not themselves POD-curves, although often interpreted as such. In this paper the most often recommended method in the statistical literature, based on likelihoods, are presented. It is shown that the methodology extends naturally to models incorporating additional parameters to model specific POD behaviors.

  13. The relationship between fundamental movement skill proficiency and physical self-confidence among adolescents.

    Science.gov (United States)

    McGrane, Bronagh; Belton, Sarahjane; Powell, Danielle; Issartel, Johann

    2017-09-01

    This study aims to assess fundamental movement skill (FMS) proficiency, physical self-confidence levels, and the relationship between these variables and gender differences among adolescents. Three hundred and ninety five adolescents aged 13.78 years (SD = ±1.2) from 20 schools were involved in this study. The Test of Gross Motor Development-2nd Edition (TGMD), TGMD-2 and Victorian Skills Manual were used to assess 15 FMS. Participants' physical self-confidence was also assessed using a valid skill-specific scale. A significant correlation was observed between FMS proficiency and physical self-confidence for females only (r = 0.305, P self-confidence levels than females (P = 0.001). Males scored significantly higher than females in FMS proficiency (P self-confidence group were significantly less proficient at FMS than the medium (P self-confidence groups (P self-confidence and FMS proficiency.

  14. Diagnostic interval and mortality in colorectal cancer

    DEFF Research Database (Denmark)

    Tørring, Marie Louise; Frydenberg, Morten; Hamilton, William

    2012-01-01

    Objective To test the theory of a U-shaped association between time from the first presentation of symptoms in primary care to the diagnosis (the diagnostic interval) and mortality after diagnosis of colorectal cancer (CRC). Study Design and Setting Three population-based studies in Denmark...

  15. Learned Interval Time Facilitates Associate Memory Retrieval

    Science.gov (United States)

    van de Ven, Vincent; Kochs, Sarah; Smulders, Fren; De Weerd, Peter

    2017-01-01

    The extent to which time is represented in memory remains underinvestigated. We designed a time paired associate task (TPAT) in which participants implicitly learned cue-time-target associations between cue-target pairs and specific cue-target intervals. During subsequent memory testing, participants showed increased accuracy of identifying…

  16. Reference intervals for selected serum biochemistry analytes in cheetahs (Acinonyx jubatus

    Directory of Open Access Journals (Sweden)

    Gavin C. Hudson-Lamb

    2016-02-01

    Full Text Available Published haematologic and serum biochemistry reference intervals are very scarce for captive cheetahs and even more for free-ranging cheetahs. The current study was performed to establish reference intervals for selected serum biochemistry analytes in cheetahs. Baseline serum biochemistry analytes were analysed from 66 healthy Namibian cheetahs. Samples were collected from 30 captive cheetahs at the AfriCat Foundation and 36 free-ranging cheetahs from central Namibia. The effects of captivity-status, age, sex and haemolysis score on the tested serum analytes were investigated. The biochemistry analytes that were measured were sodium, potassium, magnesium, chloride, urea and creatinine. The 90% confidence interval of the reference limits was obtained using the non-parametric bootstrap method. Reference intervals were preferentially determined by the non-parametric method and were as follows: sodium (128 mmol/L – 166 mmol/L, potassium (3.9 mmol/L – 5.2 mmol/L, magnesium (0.8 mmol/L – 1.2 mmol/L, chloride (97 mmol/L – 130 mmol/L, urea (8.2 mmol/L – 25.1 mmol/L and creatinine (88 µmol/L – 288 µmol/L. Reference intervals from the current study were compared with International Species Information System values for cheetahs and found to be narrower. Moreover, age, sex and haemolysis score had no significant effect on the serum analytes in this study. Separate reference intervals for captive and free-ranging cheetahs were also determined. Captive cheetahs had higher urea values, most likely due to dietary factors. This study is the first to establish reference intervals for serum biochemistry analytes in cheetahs according to international guidelines. These results can be used for future health and disease assessments in both captive and free-ranging cheetahs.

  17. Automatic Error Analysis Using Intervals

    Science.gov (United States)

    Rothwell, E. J.; Cloud, M. J.

    2012-01-01

    A technique for automatic error analysis using interval mathematics is introduced. A comparison to standard error propagation methods shows that in cases involving complicated formulas, the interval approach gives comparable error estimates with much less effort. Several examples are considered, and numerical errors are computed using the INTLAB…

  18. Replication, falsification, and the crisis of confidence in social psychology.

    Science.gov (United States)

    Earp, Brian D; Trafimow, David

    2015-01-01

    The (latest) crisis in confidence in social psychology has generated much heated discussion about the importance of replication, including how it should be carried out as well as interpreted by scholars in the field. For example, what does it mean if a replication attempt "fails"-does it mean that the original results, or the theory that predicted them, have been falsified? And how should "failed" replications affect our belief in the validity of the original research? In this paper, we consider the replication debate from a historical and philosophical perspective, and provide a conceptual analysis of both replication and falsification as they pertain to this important discussion. Along the way, we highlight the importance of auxiliary assumptions (for both testing theories and attempting replications), and introduce a Bayesian framework for assessing "failed" replications in terms of how they should affect our confidence in original findings.

  19. Standard-interval size affects interval-discrimination thresholds for pure-tone melodic pitch intervals.

    Science.gov (United States)

    McClaskey, Carolyn M

    2017-11-01

    Our ability to discriminate between pitch intervals of different sizes is not only an important aspect of speech and music perception, but also a useful means of evaluating higher-level pitch perception. The current study examined how pitch-interval discrimination was affected by the size of the intervals being compared, and by musical training. Using an adaptive procedure, pitch-interval discrimination thresholds were measured for sequentially presented pure-tone intervals with standard intervals of 1 semitone (minor second), 6 semitones (the tri-tone), and 7 semitones (perfect fifth). Listeners were classified into three groups based on musical experience: non-musicians had less than 3 years of informal musical experience, amateur musicians had at least 10 years of experience but no formal music theory training, and expert musicians had at least 12 years of experience with 1 year of formal ear training, and were either currently pursuing or had earned a Bachelor's degree as either a music major or music minor. Consistent with previous studies, discrimination thresholds obtained from expert musicians were significantly lower than those from other listeners. Thresholds also significantly varied with the magnitude of the reference interval and were higher for conditions with a 6- or 7-semitone standard than a 1-semitone standard. These data show that interval-discrimination thresholds are strongly affected by the size of the standard interval. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. INTERVALS OPTIMIZATION OF SYSTEMS INFORMATION SECURITY INSPECTION

    Directory of Open Access Journals (Sweden)

    V. A. Bogatyrev

    2014-09-01

    Full Text Available A Markov model is suggested for secure information systems, functioning under conditions of destructive impacts, which aftereffects are found by on-line and test control. It is assumed that on-line control, in contrast to the test one, is char- acterized by the limited control completeness, but does not require the stopping of computational process. The aim of re- search is to create models that optimize intervals of test control initialization by the criterion of probability maximization for system stay in the ready state to secure fulfillment of the functional requests and minimization of the dangerous system states in view of the uncertainty and intensity variance of the destructive impacts. Variants of testing intervals optimization are con- sidered depending on the intensity of destructive impacts by the criterion of the maximum system availability for the safe execution of queries. Optimization is carried out with and without adaptation to the actual intensity change of destructive impacts. The efficiency of adaptive change for testing periods is shown depending on the observed activity of destructive impacts. The solution of optimization problem is obtained by built-in tools of computer mathematics Mathcad 15, including symbolic mathematics for solution of systems of algebraic equations. The proposed models and methods of determining the optimal testing intervals can find their application in the system design of computer systems and networks of critical applications, working under conditions of destabilizing actions with the increased requirements for their safety.

  1. Handover education improves skill and confidence.

    Science.gov (United States)

    Stojan, Jennifer; Mullan, Patricia; Fitzgerald, James; Lypson, Monica; Christner, Jennifer; Haftel, Hilary; Schiller, Jocelyn

    2016-12-01

    Despite the frequency of patient-care handovers and vulnerability to errors, medical schools infrequently teach handover skills. Our study evaluated the impact of a medical school handover curriculum on students' performance, as rated by faculty members, peers and self-assessment. Nineteen fourth-year medical students participated in a handover curriculum that included a workshop and three directly observed patient handovers, with feedback from faculty members. Multivariate repeated-measures analysis evaluated faculty member, peer, and self-rated performance over time. Students' self-assessed confidence in performing handovers prior to, at the end of, and 8-12 months after the curriculum was also analysed. Faculty member, peer and self-assessments showed that students' performance significantly improved after the curriculum, on handover content, clinical judgment and overall performance (p skills DISCUSSION: A handover curriculum appears to improve medical students' handover performance, as evaluated by independent ratings from faculty members, peers and the students themselves, in addition to improving the students' confidence. © 2015 John Wiley & Sons Ltd.

  2. The relationship between confidence in charitable organizations and volunteering revisited

    NARCIS (Netherlands)

    Bekkers, René H.F.P.; Bowman, Woods

    2009-01-01

    Confidence in charitable organizations (charitable confidence) would seem to be an important prerequisite for philanthropic behavior. Previous research relying on cross-sectional data has suggested that volunteering promotes charitable confidence and vice versa. This research note, using new

  3. Metacognition and Confidence: Comparing Math to Other Academic Subjects

    Directory of Open Access Journals (Sweden)

    Shanna eErickson

    2015-06-01

    Full Text Available Two studies addressed student metacognition in math, measuring confidence accuracy about math performance. Underconfidence would be expected in light of pervasive math anxiety. However, one might alternatively expect overconfidence based on previous results showing overconfidence in other subject domains. Metacognitive judgments and performance were assessed for biology, literature, and mathematics tests. In Study 1, high school students took three different tests and provided estimates of their performance both before and after taking each test. In Study 2, undergraduates similarly took three shortened SAT II Subject Tests. Students were overconfident in predicting math performance, indeed showing greater overconfidence compared to other academic subjects. It appears that both overconfidence and anxiety can adversely affect metacognitive ability and can lead to math avoidance. The results have implications for educational practice and other environments that require extensive use of math.

  4. The effect of instrumental timbre on interval discrimination.

    Directory of Open Access Journals (Sweden)

    Jean Mary Zarate

    Full Text Available We tested non-musicians and musicians in an auditory psychophysical experiment to assess the effects of timbre manipulation on pitch-interval discrimination. Both groups were asked to indicate the larger of two presented intervals, comprised of four sequentially presented pitches; the second or fourth stimulus within a trial was either a sinusoidal (or "pure", flute, piano, or synthetic voice tone, while the remaining three stimuli were all pure tones. The interval-discrimination tasks were administered parametrically to assess performance across varying pitch distances between intervals ("interval-differences". Irrespective of timbre, musicians displayed a steady improvement across interval-differences, while non-musicians only demonstrated enhanced interval discrimination at an interval-difference of 100 cents (one semitone in Western music. Surprisingly, the best discrimination performance across both groups was observed with pure-tone intervals, followed by intervals containing a piano tone. More specifically, we observed that: 1 timbre changes within a trial affect interval discrimination; and 2 the broad spectral characteristics of an instrumental timbre may influence perceived pitch or interval magnitude and make interval discrimination more difficult.

  5. Notes on interval estimation of the gamma correlation under stratified random sampling.

    Science.gov (United States)

    Lui, Kung-Jong; Chang, Kuang-Chao

    2012-07-01

    We have developed four asymptotic interval estimators in closed forms for the gamma correlation under stratified random sampling, including the confidence interval based on the most commonly used weighted-least-squares (WLS) approach (CIWLS), the confidence interval calculated from the Mantel-Haenszel (MH) type estimator with the Fisher-type transformation (CIMHT), the confidence interval using the fundamental idea of Fieller's Theorem (CIFT) and the confidence interval derived from a monotonic function of the WLS estimator of Agresti's α with the logarithmic transformation (MWLSLR). To evaluate the finite-sample performance of these four interval estimators and note the possible loss of accuracy in application of both Wald's confidence interval and MWLSLR using pooled data without accounting for stratification, we employ Monte Carlo simulation. We use the data taken from a general social survey studying the association between the income level and job satisfaction with strata formed by genders in black Americans published elsewhere to illustrate the practical use of these interval estimators. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Interval estimation of the mass fractal dimension for anisotropic sampling percolation clusters

    OpenAIRE

    Moskalev, P. V.; Grebennikov, K. V.; Shitov, V. V.

    2011-01-01

    This report focuses on the dependencies for the center and radius of the confidence interval that arise when estimating the mass fractal dimensions of anisotropic sampling clusters in the site percolation model.

  7. Interval estimation of the mass fractal dimension for isotropic sampling percolation clusters

    OpenAIRE

    Moskalev, P. V.; Grebennikov, K. V.; Shitov, V. V.

    2011-01-01

    This report focuses on the dependencies for the center and radius of the confidence interval that arise when estimating the mass fractal dimensions of isotropic sampling clusters in the site percolation model.

  8. Confidence as Bayesian Probability: From Neural Origins to Behavior.

    Science.gov (United States)

    Meyniel, Florent; Sigman, Mariano; Mainen, Zachary F

    2015-10-07

    Research on confidence spreads across several sub-fields of psychology and neuroscience. Here, we explore how a definition of confidence as Bayesian probability can unify these viewpoints. This computational view entails that there are distinct forms in which confidence is represented and used in the brain, including distributional confidence, pertaining to neural representations of probability distributions, and summary confidence, pertaining to scalar summaries of those distributions. Summary confidence is, normatively, derived or "read out" from distributional confidence. Neural implementations of readout will trade off optimality versus flexibility of routing across brain systems, allowing confidence to serve diverse cognitive functions. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Confidence crisis of results in biomechanics research.

    Science.gov (United States)

    Knudson, Duane

    2017-11-01

    Many biomechanics studies have small sample sizes and incorrect statistical analyses, so reporting of inaccurate inferences and inflated magnitude of effects are common in the field. This review examines these issues in biomechanics research and summarises potential solutions from research in other fields to increase the confidence in the experimental effects reported in biomechanics. Authors, reviewers and editors of biomechanics research reports are encouraged to improve sample sizes and the resulting statistical power, improve reporting transparency, improve the rigour of statistical analyses used, and increase the acceptance of replication studies to improve the validity of inferences from data in biomechanics research. The application of sports biomechanics research results would also improve if a larger percentage of unbiased effects and their uncertainty were reported in the literature.

  10. The Relationship Between Eyewitness Confidence and Identification Accuracy: A New Synthesis.

    Science.gov (United States)

    Wixted, John T; Wells, Gary L

    2017-05-01

    The U.S. legal system increasingly accepts the idea that the confidence expressed by an eyewitness who identified a suspect from a lineup provides little information as to the accuracy of that identification. There was a time when this pessimistic assessment was entirely reasonable because of the questionable eyewitness-identification procedures that police commonly employed. However, after more than 30 years of eyewitness-identification research, our understanding of how to properly conduct a lineup has evolved considerably, and the time seems ripe to ask how eyewitness confidence informs accuracy under more pristine testing conditions (e.g., initial, uncontaminated memory tests using fair lineups, with no lineup administrator influence, and with an immediate confidence statement). Under those conditions, mock-crime studies and police department field studies have consistently shown that, for adults, (a) confidence and accuracy are strongly related and (b) high-confidence suspect identifications are remarkably accurate. However, when certain non-pristine testing conditions prevail (e.g., when unfair lineups are used), the accuracy of even a high-confidence suspect ID is seriously compromised. Unfortunately, some jurisdictions have not yet made reforms that would create pristine testing conditions and, hence, our conclusions about the reliability of high-confidence identifications cannot yet be applied to those jurisdictions. However, understanding the information value of eyewitness confidence under pristine testing conditions can help the criminal justice system to simultaneously achieve both of its main objectives: to exonerate the innocent (by better appreciating that initial, low-confidence suspect identifications are error prone) and to convict the guilty (by better appreciating that initial, high-confidence suspect identifications are surprisingly accurate under proper testing conditions).

  11. The application of deep confidence network in the problem of image recognition

    Directory of Open Access Journals (Sweden)

    Chumachenko О.І.

    2016-12-01

    Full Text Available In order to study the concept of deep learning, in particular the substitution of multilayer perceptron on the corresponding network of deep confidence, computer simulations of the learning process to test voters was carried out. Multi-layer perceptron has been replaced by a network of deep confidence, consisting of successive limited Boltzmann machines. After training of a network of deep confidence algorithm of layer-wise training it was found that the use of networks of deep confidence greatly improves the accuracy of multilayer perceptron training by method of reverse distribution errors.

  12. Method for calculating the variance and prediction intervals for biomass estimates obtained from allometric equations

    CSIR Research Space (South Africa)

    Kirton, A

    2010-08-01

    Full Text Available intervals (confidence intervals for predicted values) for allometric estimates can be obtained using an example of estimating tree biomass from stem diameter. It explains how to deal with relationships which are in the power function form - a common form... for allometric relationships - and identifies the information that needs to be provided with the allometric equation if it is to be used with confidence. Correct estimation of tree biomass with known error is very important when trees are being planted...

  13. Beyond social support: Self-care confidence is key for adherence in patients with heart failure.

    Science.gov (United States)

    Hammash, Muna H; Crawford, Timothy; Shawler, Celeste; Schrader, Melanie; Lin, Chin-Yen; Shewekah, Deena; Moser, Debra K

    2017-10-01

    Adherence to treatment is crucial to improve outcomes in patients with heart failure. Good social support is associated with better adherence, but the mechanism for this association has not been well-explored. The aim of this secondary analysis was to examine whether self-care confidence mediates the relationship between social support and treatment adherence in heart failure patients hospitalized with acute exacerbation. A total of 157 inpatients with heart failure (63.5±13 years, 73% New York Heart Association class III/IV) were recruited from two hospitals located in urban areas in the USA. Participants completed the Self-Care of Heart Failure Index, the Multidimensional Perceived Social Support Scale, and the Medical Outcomes Study Specific Adherence Scale. A series of regression models were used to determine the mediation relationship. Controlling for marital status and hospital site, social support was associated with adherence ( p=0.03). When self-confidence was included in the model, the effect of social support became non-significant, indicating full mediation of the relationship between social support and adherence by self-care confidence. The indirect effect (0.04) of social support on adherence through self-confidence was significant (95% confidence interval: 0.01-0.09). Heart failure self-care confidence mediated the relationship between social support and treatment adherence. Thus interventions targeting patients' self-care confidence is essential to maximize patients' treatment adherence.

  14. Experimental uncertainty estimation and statistics for data having interval uncertainty.

    Energy Technology Data Exchange (ETDEWEB)

    Kreinovich, Vladik (Applied Biomathematics, Setauket, New York); Oberkampf, William Louis (Applied Biomathematics, Setauket, New York); Ginzburg, Lev (Applied Biomathematics, Setauket, New York); Ferson, Scott (Applied Biomathematics, Setauket, New York); Hajagos, Janos (Applied Biomathematics, Setauket, New York)

    2007-05-01

    This report addresses the characterization of measurements that include epistemic uncertainties in the form of intervals. It reviews the application of basic descriptive statistics to data sets which contain intervals rather than exclusively point estimates. It describes algorithms to compute various means, the median and other percentiles, variance, interquartile range, moments, confidence limits, and other important statistics and summarizes the computability of these statistics as a function of sample size and characteristics of the intervals in the data (degree of overlap, size and regularity of widths, etc.). It also reviews the prospects for analyzing such data sets with the methods of inferential statistics such as outlier detection and regressions. The report explores the tradeoff between measurement precision and sample size in statistical results that are sensitive to both. It also argues that an approach based on interval statistics could be a reasonable alternative to current standard methods for evaluating, expressing and propagating measurement uncertainties.

  15. Patient confidence and quality of life in idiopathic pulmonary fibrosis and sarcoidosis.

    Science.gov (United States)

    Kotecha, Jalpa; Atkins, Christopher; Wilson, Andrew

    2016-12-23

    Idiopathic pulmonary fibrosis (IPF) and sarcoidosis impact significantly on health-related quality of life (HRQOL). There are few studies on the impact of patient confidence on HRQOL in these conditions. 1. To investigate whether patient confidence is associated with HRQOL, anxiety, depression, dyspnoea or fatigue. 2. To assess if patient confidence is associated with inpatient admissions, access to community healthcare and, for IPF patients, mortality and disease severity. Study participants self-completed seven questionnaires: Hospital Anxiety and Depression Scale, EuroQol 5D (EQ5D), King's Brief Interstitial Lung Disease questionnaire, St George's Respiratory Questionnaire, MRC dyspnoea scale, Fatigue Assessment Scale and a non-validated questionnaire assessing patient confidence, symptom duration and access to community healthcare. Lung function and follow-up data were collected from hospital electronic databases. Spearman's rank correlation coefficients were calculated to assess for correlation between patient confidence, questionnaire variables and inpatient admissions. Chi-square tests were performed to assess for association between patient confidence, mortality and disease severity. 75 IPF patients and 69 sarcoidosis patients were recruited to the study. Patient confidence in IPF was significantly negatively correlated with depression and fatigue, and significantly positively correlated with EQ5D scores, but not healthcare outcomes. No associations were found between confidence and any of the variables assessed in sarcoidosis. Lower levels of confidence in IPF patients are associated with higher levels of depression and fatigue and worse HRQOL. Efforts should be made to improve patient confidence to assess the impact on HRQOL.

  16. Confidence assessment. Site descriptive modelling SDM-Site Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    2008-09-15

    distribution and size-intensity models for fractures at repository depth can only be reduced by data from underground, i.e. from fracture mapping of tunnel walls etc. Specifically it will be necessary to carry out statistical modelling of fractures in a DFN study at depth during construction work on the access ramp and shafts. Uncertainties in stress magnitude will be reduced by observations and measurements of deformation with back analysis during the construction phase. Underground mapping data from deposition tunnels will allow fore a division of the fine-grained granitoid into different rock types. This will enable thermal optimisation of the repository. The next step in confidence building would be to predict conditions and impacts from underground tunnels. Tunnel data will provide information about the fracture size distribution at the relevant depths. The underground excavations will also provide possibilities for short-range interference tests at relevant depth.

  17. Effects of postpartum anxiety disorders and depression on maternal self-confidence.

    Science.gov (United States)

    Reck, Corinna; Noe, Daniela; Gerstenlauer, Jakob; Stehle, Eva

    2012-04-01

    Low maternal self-confidence may damage the early mother-infant relationship and negatively influence infant development. The goal of this study was to test whether a current and previous history of DSM-IV anxiety and depressive disorders is associated with maternal self-confidence two weeks after delivery. Postpartum anxiety disorder and depression was diagnosed according to DSM-IV criteria in a community sample of 798 women. The data showed a significant link between current postpartum anxiety and depressive disorders and maternal self-confidence. Furthermore, women with a depression or anxiety disorder in their previous psychiatric history scored lower in maternal self-confidence. There is a need for appropriate preventive programmes to promote maternal self-confidence. With such programmes it is possible to prevent infant developmental disorders which might result from reduced feelings of maternal self-confidence and associated maternal interaction behaviour. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Enhancing the Robustness of the Posterior-Based Confidence Measures Using Entropy Information for Speech Recognition

    Science.gov (United States)

    Sun, Yanqing; Zhou, Yu; Zhao, Qingwei; Zhang, Pengyuan; Pan, Fuping; Yan, Yonghong

    In this paper, the robustness of the posterior-based confidence measures is improved by utilizing entropy information, which is calculated for speech-unit-level posteriors using only the best recognition result, without requiring a larger computational load than conventional methods. Using different normalization methods, two posterior-based entropy confidence measures are proposed. Practical details are discussed for two typical levels of hidden Markov model (HMM)-based posterior confidence measures, and both levels are compared in terms of their performances. Experiments show that the entropy information results in significant improvements in the posterior-based confidence measures. The absolute improvements of the out-of-vocabulary (OOV) rejection rate are more than 20% for both the phoneme-level confidence measures and the state-level confidence measures for our embedded test sets, without a significant decline of the in-vocabulary accuracy.

  19. Creating an Upper-Confidence-Tree Program for Havannah

    Science.gov (United States)

    Teytaud, Fabien; Teytaud, Olivier

    Monte-Carlo Tree Search and Upper Confidence Bounds provided huge improvements in computer-Go. In this paper, we test the generality of the approach by experimenting on the game, Havannah, which is known for being especially difficult for computers. We show that the same results hold, with slight differences related to the absence of clearly known patterns for the game of Havannah, in spite of the fact that Havannah is more related to connection games like Hex than to territory games like Go.

  20. Attitudes and Confidence in the Integration of Psychiatry Scale.

    Science.gov (United States)

    Fiedorowicz, Jess G; Dantz, Bezalel; Blazek, Mary C

    2016-04-01

    The authors sought to measure attitudes and confidence in the integration of psychiatry into other fields of medicine. The Attitudes and Confidence in Integration of Psychiatry in Medicine (ACIP) scale was developed through discussion with content experts across disciplines and pilot testing of items and administered to third- and fourth-year medical students at University of Iowa, University of Michigan, Rush University for validation, focused on assessment of variability, internal consistency, factor structure, and test-retest reliability. A total of 310 medical students completed the survey (35% participation rate). The scale had a high internal consistency (Cronbach's alpha = 0.88) and was without ceiling or floor effects. Students rated the integration of psychiatry into the practice of surgery and its subspecialties as less relevant than its integration into other specialties; however, scores were not biased by students' interest in procedural vs. non-procedural specialties. Test-retest reliability was high (Cronbach's alpha = 0.90). The ACIP may serve a useful role in determining the outcome of educational efforts toward integrated care.

  1. Comparing interval estimates for small sample ordinal CFA models.

    Science.gov (United States)

    Natesan, Prathiba

    2015-01-01

    Robust maximum likelihood (RML) and asymptotically generalized least squares (AGLS) methods have been recommended for fitting ordinal structural equation models. Studies show that some of these methods underestimate standard errors. However, these studies have not investigated the coverage and bias of interval estimates. An estimate with a reasonable standard error could still be severely biased. This can only be known by systematically investigating the interval estimates. The present study compares Bayesian, RML, and AGLS interval estimates of factor correlations in ordinal confirmatory factor analysis models (CFA) for small sample data. Six sample sizes, 3 factor correlations, and 2 factor score distributions (multivariate normal and multivariate mildly skewed) were studied. Two Bayesian prior specifications, informative and relatively less informative were studied. Undercoverage of confidence intervals and underestimation of standard errors was common in non-Bayesian methods. Underestimated standard errors may lead to inflated Type-I error rates. Non-Bayesian intervals were more positive biased than negatively biased, that is, most intervals that did not contain the true value were greater than the true value. Some non-Bayesian methods had non-converging and inadmissible solutions for small samples and non-normal data. Bayesian empirical standard error estimates for informative and relatively less informative priors were closer to the average standard errors of the estimates. The coverage of Bayesian credibility intervals was closer to what was expected with overcoverage in a few cases. Although some Bayesian credibility intervals were wider, they reflected the nature of statistical uncertainty that comes with the data (e.g., small sample). Bayesian point estimates were also more accurate than non-Bayesian estimates. The results illustrate the importance of analyzing coverage and bias of interval estimates, and how ignoring interval estimates can be misleading

  2. Confidence as motivational expressions of interest, utility, and other influences: Exploring under-confidence and over-confidence in science students at secondary school

    OpenAIRE

    Sheldrake, Richard

    2016-01-01

    An enhanced understanding of how students’ self-confidence is influenced benefits educational practice and motivational theories. For 1523 students in 12 secondary schools in England, science self-confidence was predicted by various factors: current self-confidence (self-concept) was most strongly predicted by received praise, current grades, and interest in science; self-confidence for future attainment (self-efficacy) was most strongly predicted by current grades and perceived utility of sc...

  3. Mediated Sources of Public Confidence: Lazarsfeld and Merton Revisited.

    Science.gov (United States)

    Simonson, Peter

    1999-01-01

    Contributes to scholarship on mass media's role in generating public confidence. Discusses the current crisis of confidence, confidence as "faith-together," varied routes by which media confer status, and ways both journalistic expose and public debate can generate cynicism and undercut public confidence. Sketches three types of civil…

  4. Supplementary Table 1. Results of association test with CAPN10 ...

    Indian Academy of Sciences (India)

    maheswari velmurugan

    Odds ratio - OR, CI- confidence interval, HW- hardy-Weinberg, MAF- minor allele frequency;. A- adenine; G, guanine. A chi squared test was performed to evaluate the association between single nucleotide polymorphisms and PCOS; the genotypes were verified to comply with the. Hardy – Weinberg equilibrium; odds ratio ...

  5. Cytotoxicity testing of aqueous extract of bitter leaf ( Vernonia ...

    African Journals Online (AJOL)

    Cytotoxicity testing of aqueous extract of bitter leaf ( Vernonia amygdalina Del ) and sniper 1000EC (2,3 dichlorovinyl dimethyl phosphate) using the Alium cepa ... 96 hours and EC50 values at 95% confidence interval was determined from a plot of root length against sample concentrations using Microsoft Excel software.

  6. Eyewitness confidence : the relation between accuracy and confidence in episodic memory

    NARCIS (Netherlands)

    Odinot, Geralda

    2008-01-01

    Many decisions in the legal system are based on eyewitness evidence. It seems to be a matter of common sense that the level of confidence expressed by a witness can be used as a diagnostic tool to discriminate between accurate and inaccurate memories. Contrary to this general belief, the bulk of

  7. Confidence intervals for ARMA-GARCH Value-at-Risk : The case of heavy tails and skewness

    NARCIS (Netherlands)

    Spierdijk, Laura

    It is a well-known result that, when the ARMA GARCH model errors lack a finite fourth moment, the asymptotic distribution of the quasi-maximum likelihood estimator may not be Normal. In such a scenario the conventional bootstrap turns out inconsistent. Surprisingly, simulations show that the

  8. Derivation of confidence intervals of service measures in a base-stock inventory control system with low-frequent demand

    DEFF Research Database (Denmark)

    Larsen, Christian

    We explore a base-stock system with backlogging where the demand process is a compound renewal process and the compound element is a delayed geometric distribution. For this setting it is proven in [4] that the long-run average service measures order fill rate (OFR) and volume fill rate (VFR) are...

  9. Derivation of confidence intervals of service measures in a base-stock inventory control system with low-frequent demand

    DEFF Research Database (Denmark)

    Larsen, Christian

    2011-01-01

    We explore a base-stock system with backlogging where the demand process is a compound renewal process and the compound element is a delayed geometric distribution. For this setting it holds that the long-run average service measures order fill rate (OFR) and volume fill rate (VFR) are equal in v...

  10. Meta-analysis to refine map position and reduce confidence intervals for delayed canopy wilting QTLs in soybean

    Science.gov (United States)

    Slow canopy wilting in soybean has been identified as a potentially beneficial trait for ameliorating drought effects on yield. Previous research identified QTLs for slow wilting from two different bi-parental populations and this information was combined with data from three other populations to id...

  11. Noise annoyance from stationary sources: Relationships with exposure metric day-evening-night level (DENL) and their confidence intervals

    NARCIS (Netherlands)

    Miedema, H.M.E.; Vos, H.

    2004-01-01

    Relationships between exposure to noise [metric: day-evening-night levels (DENL)] from stationary sources (shunting yards, a seasonal industry, and other industries) and annoyance are presented. Curves are presented for expected annoyance score, the percentage "highly annoyed" (%HA, cutoff at 72 on

  12. A new model for cork weight estimation in Northern Portugal with methodology for construction of confidence intervals

    Science.gov (United States)

    Teresa J.F. Fonseca; Bernard R. Parresol

    2001-01-01

    Cork, a unique biological material, is a highly valued non-timber forest product. Portugal is the leading producer of cork with 52 percent of the world production. Tree cork weight models have been developed for Southern Portugal, but there are no representative published models for Northern Portugal. Because cork trees may have a different form between Northern and...

  13. Medical students as EMTs: skill building, confidence and professional formation

    Directory of Open Access Journals (Sweden)

    Thomas Kwiatkowski

    2014-07-01

    Full Text Available Objective: The first course of the medical curriculum at the Hofstra North Shore-LIJ School of Medicine, From the Person to the Professional: Challenges, Privileges and Responsibilities, provides an innovative early clinical immersion. The course content specific to the Emergency Medical Technician (EMT curriculum was developed using the New York State Emergency Medical Technician curriculum. Students gain early legitimate clinical experience and practice clinical skills as team members in the pre-hospital environment. We hypothesized this novel curriculum would increase students’ confidence in their ability to perform patient care skills and enhance students’ comfort with team-building skills early in their training. Methods: Quantitative and qualitative data were collected from first-year medical students (n=97 through a survey developed to assess students’ confidence in patient care and team-building skills. The survey was completed prior to medical school, during the final week of the course, and at the end of their first year. A paired-samples t-test was conducted to compare self-ratings on 12 patient care and 12 team-building skills before and after the course, and a theme analysis was conducted to examine open-ended responses. Results: Following the course, student confidence in patient care skills showed a significant increase from baseline (p<0.05 for all identified skills. Student confidence in team-building skills showed a significant increase (p<0.05 in 4 of the 12 identified skills. By the end of the first year, 84% of the first-year students reported the EMT curriculum had ‘some impact’ to ‘great impact’ on their patient care skills, while 72% reported the EMT curriculum had ‘some impact’ to ‘great impact’ on their team-building skills. Conclusions: The incorporation of EMT training early in a medical school curriculum provides students with meaningful clinical experiences that increase their self

  14. Self-confidence and knowledge of German ICU physicians in palliative care - a multicentre prospective study.

    Science.gov (United States)

    Krautheim, Veronika; Schmitz, Andrea; Benze, Gesine; Standl, Thomas; Schiessl, Christine; Waldeyer, Wolfgang; Hapfelmeier, Alexander; Kochs, Eberhard F; Schneider, Gerhard; Wagner, Klaus J; Schulz, Christian M

    2017-11-22

    Little is known about ICU physicians' self-confidence and knowledge related to palliative care. Our objective was to investigate self-confidence and knowledge of German ICU physicians related to palliative care, and to assess the impact of work experience, gender, specialty and additional certifications in pain or palliative medicine. In a multicentre prospective observational study ICU physicians of ten hospitals were asked to rate their self-confidence and to complete a multiple choice questionnaire for the assessment of knowledge. Beyond descriptive statistics and non-parametric tests for group comparisons, linear regression analysis was used to assess the impact of independent variable on self-confidence and knowledge. Spearman's rank test was calculated. 55% of answers in the knowledge test were correct and more than half of the participants rated themselves as "rather confident" or "confident". Linear regression analysis revealed that an additional certificate in either pain or palliative medicine significantly increased both knowledge and self-confidence, but only 15 out of 137 participants had at least one of those certificates. Relation between self-confidence and the results of the knowledge test was weak (r = 0.270 in female) and very weak (r = -0.007 in male). Although the questionnaire needs improvement according to the item analysis, it appears that, with respect to palliative care, ICU Physicians' self-confidence is not related to their knowledge. An additional certificate in either pain or palliative medicine was positively correlated to both self-confidence and knowledge. However, only a minority of the participants were qualified through such a certificate.

  15. Updating representations of temporal intervals.

    Science.gov (United States)

    Danckert, James; Anderson, Britt

    2015-12-01

    Effectively engaging with the world depends on accurate representations of the regularities that make up that world-what we call mental models. The success of any mental model depends on the ability to adapt to changes-to 'update' the model. In prior work, we have shown that damage to the right hemisphere of the brain impairs the ability to update mental models across a range of tasks. Given the disparate nature of the tasks we have employed in this prior work (i.e. statistical learning, language acquisition, position priming, perceptual ambiguity, strategic game play), we propose that a cognitive module important for updating mental representations should be generic, in the sense that it is invoked across multiple cognitive and perceptual domains. To date, the majority of our tasks have been visual in nature. Given the ubiquity and import of temporal information in sensory experience, we examined the ability to build and update mental models of time. We had healthy individuals complete a temporal prediction task in which intervals were initially drawn from one temporal range before an unannounced switch to a different range of intervals. Separate groups had the second range of intervals switch to one that contained either longer or shorter intervals than the first range. Both groups showed significant positive correlations between perceptual and prediction accuracy. While each group updated mental models of temporal intervals, those exposed to shorter intervals did so more efficiently. Our results support the notion of generic capacity to update regularities in the environment-in this instance based on temporal information. The task developed here is well suited to investigations in neurological patients and in neuroimaging settings.

  16. Business confidence still high in Zimbabwe.

    Science.gov (United States)

    Amanor-wilks, D

    1995-12-01

    Business confidence has not been affected in Zimbabwe despite the AIDS epidemic in that country. An Australian mining company has recruited people to work at its platinum mine in Zimbabwe and also instituted an AIDS awareness program. The National Chamber of Commerce disclosed that semiskilled and unskilled workers who are the "easiest to replace" have been most affected by the epidemic. The impact of AIDS has not been as bad as had been predicted several years ago. By the end of the 1990s, however, there might be a skills shortage. The first AIDS case was detected in 1985 in Zimbabwe. By the end of 1995 a cumulative total of 38,500 cases had been reported, but the National AIDS Control Program believes that the true figure is over 100,000. The estimated number of HIV-infected people is about 1 million. The most economically productive age group (30-50) has the highest rates of infection. Transport is affected most, followed by mining and commercial farming. Infection rates among miners are estimated to be 20-30% and the rates are the highest at the mines on the major transport routes. The mining industry has not had any problems in recruiting labor, but, increasingly, deaths are AIDS-related. The growing sex industry at the mines has accelerated the spread of HIV. In addition, small mines do not have AIDS awareness programs in place. The National Employment Council runs a project for the transport industry, which seeks to intensify AIDS campaigns at truck stops. This also entails talks to drivers about AIDS; courses for police, nurses, and sex workers; and the distribution of condoms. In commercial farming, two-thirds of workers are unskilled casual laborers who live in squalid conditions that foster the spread of AIDS. At these farms there is also a growing number of orphans, whose number is estimated to rise to 60,000 by the late 1990s.

  17. Confidence and self-attribution bias in an artificial stock market

    Science.gov (United States)

    Bertella, Mario A.; Pires, Felipe R.; Rego, Henio H. A.; Vodenska, Irena; Stanley, H. Eugene

    2017-01-01

    Using an agent-based model we examine the dynamics of stock price fluctuations and their rates of return in an artificial financial market composed of fundamentalist and chartist agents with and without confidence. We find that chartist agents who are confident generate higher price and rate of return volatilities than those who are not. We also find that kurtosis and skewness are lower in our simulation study of agents who are not confident. We show that the stock price and confidence index—both generated by our model—are cointegrated and that stock price affects confidence index but confidence index does not affect stock price. We next compare the results of our model with the S&P 500 index and its respective stock market confidence index using cointegration and Granger tests. As in our model, we find that stock prices drive their respective confidence indices, but that the opposite relationship, i.e., the assumption that confidence indices drive stock prices, is not significant. PMID:28231255

  18. Confidence and self-attribution bias in an artificial stock market.

    Science.gov (United States)

    Bertella, Mario A; Pires, Felipe R; Rego, Henio H A; Silva, Jonathas N; Vodenska, Irena; Stanley, H Eugene

    2017-01-01

    Using an agent-based model we examine the dynamics of stock price fluctuations and their rates of return in an artificial financial market composed of fundamentalist and chartist agents with and without confidence. We find that chartist agents who are confident generate higher price and rate of return volatilities than those who are not. We also find that kurtosis and skewness are lower in our simulation study of agents who are not confident. We show that the stock price and confidence index-both generated by our model-are cointegrated and that stock price affects confidence index but confidence index does not affect stock price. We next compare the results of our model with the S&P 500 index and its respective stock market confidence index using cointegration and Granger tests. As in our model, we find that stock prices drive their respective confidence indices, but that the opposite relationship, i.e., the assumption that confidence indices drive stock prices, is not significant.

  19. High-intensity interval training versus moderate-intensity continuous training on exercise capacity and quality of life in patients with coronary artery disease: A systematic review and meta-analysis.

    Science.gov (United States)

    Gomes-Neto, Mansueto; Durães, André R; Reis, Helena F Correia Dos; Neves, Victor R; Martinez, Bruno P; Carvalho, Vitor O

    2017-11-01

    Background Exercise is an effective strategy for reducing total and cardiovascular mortality in patients with coronary artery disease. However, it is not clear which modality is best. We performed a meta-analysis to investigate the effects of high-intensity interval versus moderate-intensity continuous training of coronary artery disease patients. Methods We searched MEDLINE, PEDro, LILACS, SciELO and the Cochrane Library (from the earliest date available to November 2016) for controlled trials that evaluated the effects of high-intensity interval versus moderate-intensity continuous training for coronary artery disease patients. Weighted mean differences and 95% confidence intervals were calculated, and heterogeneity was assessed using the I2 test. Results Twelve studies met the study criteria, including 609 patients. High-intensity interval training resulted in improvement in peak oxygen uptake weighted mean difference (1.3 ml/kg/min, 95% confidence interval: 0.6-1.9, n = 594) compared with moderate-intensity continuous training. No significant difference in physical, emotional, and social domain of quality of life was found for participants for participants in the high-intensity interval training group compared with the moderate-intensity continuous training group. Sub-analysis of three studies with isocaloric exercise training showed no significant difference in peak oxygen uptake weighted mean difference (0.4 ml/kg/min, 95% confidence interval: -0.1-0.9, n = 137) for participants in the high-intensity interval training group compared with moderate-intensity continuous training group. Conclusions High-intensity interval training may improve peak oxygen uptake and should be considered as a component of care of coronary artery disease patients. However, this superiority disappeared when isocaloric protocol is compared.

  20. Interval matrices: Regularity generates singularity

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří; Shary, S.P.

    2018-01-01

    Roč. 540, 1 March (2018), s. 149-159 ISSN 0024-3795 Institutional support: RVO:67985807 Keywords : interval matrix * regularity * singularity * P-matrix * absolute value equation * diagonally singilarizable matrix Subject RIV: BA - General Mathematics Impact factor: 0.973, year: 2016

  1. Assignment Confidence in Localization of the Hand Motor Cortex: Comparison of Structural Imaging With Functional MRI.

    Science.gov (United States)

    Sahin, Neslin; Mohan, Suyash; Maralani, Pejman J; Duddukuri, Srikalyan; O'Rourke, Donald M; Melhem, Elias R; Wolf, Ronald L

    2016-12-01

    The purpose of this study was to assign confidence levels to structural MRI and functional MRI (fMRI) for localization of the primary motor cortex. Ninety-one fMRI studies with at least one motor task (178 hemispheres) were identified. Three anatomic assessments were used to localize the primary motor cortex: relation between the superior frontal sulcus and precentral sulcus; cortical thickness; and configuration of the precentral knob. In 105 hemispheres, interreader agreement was assessed for two investigators with different experience levels. Confidence ratings from 0 to 5 (0, no confidence; 5, 100% confidence) were assigned for fMRI and each anatomic localization method. Cortical thickness had the highest confidence rating (mean, 4.90 ± 0.47 [SD]) with only one failure. The relation between the superior frontal sulcus and precentral sulcus had the lowest confidence rating (4.33 ± 0.91) with three failures. The greatest statistical significance was observed for the cortical thickness and superior frontal sulcus-precentral sulcus methods (post hoc Bonferroni test, p Confidence rating scores were significantly higher for the cortical thickness sign than for fMRI results (4.72 ± 0.54) for a single motor task (post hoc Bonferroni test, p = 0.006); however, the mean confidence rating for fMRI improved to 4.87 ± 0.36 when additional motor tasks were performed. Interreader differences were least for the cortical thickness sign (paired t test, t = 4.25, p confidence regarding localization of the primary motor cortex; however, localization of motor function is more specific when combined with fMRI findings. Multiple techniques can be used to increase confidence in identifying the hand motor cortex.

  2. Haematological reference intervals in a multiethnic population.

    Science.gov (United States)

    Ambayya, Angeli; Su, Anselm Ting; Osman, Nadila Haryani; Nik-Samsudin, Nik Rosnita; Khalid, Khadijah; Chang, Kian Meng; Sathar, Jameela; Rajasuriar, Jay Suriar; Yegappan, Subramanian

    2014-01-01

    Similar to other populations, full blood count reference (FBC) intervals in Malaysia are generally derived from non-Malaysian subjects. However, numerous studies have shown significant differences between and within populations supporting the need for population specific intervals. Two thousand seven hundred twenty five apparently healthy adults comprising all ages, both genders and three principal races were recruited through voluntary participation. FBC was performed on two analysers, Sysmex XE-5000 and Unicel DxH 800, in addition to blood smears and haemoglobin analysis. Serum ferritin, soluble transferrin receptor and C-reactive protein assays were performed in selected subjects. All parameters of qualified subjects were tested for normality followed by determination of reference intervals, measures of central tendency and dispersion along with point estimates for each subgroup. Complete data was available in 2440 subjects of whom 56% (907 women and 469 men) were included in reference interval calculation. Compared to other populations there were significant differences for haemoglobin, red blood cell count, platelet count and haematocrit in Malaysians. There were differences between men and women, and between younger and older men; unlike in other populations, haemoglobin was similar in younger and older women. However ethnicity and smoking had little impact. 70% of anemia in premenopausal women, 24% in postmenopausal women and 20% of males is attributable to iron deficiency. There was excellent correlation between Sysmex XE-5000 and Unicel DxH 800. Our data confirms the importance of population specific haematological parameters and supports the need for local guidelines rather than adoption of generalised reference intervals and cut-offs.

  3. Haematological reference intervals in a multiethnic population.

    Directory of Open Access Journals (Sweden)

    Angeli Ambayya

    Full Text Available INTRODUCTION: Similar to other populations, full blood count reference (FBC intervals in Malaysia are generally derived from non-Malaysian subjects. However, numerous studies have shown significant differences between and within populations supporting the need for population specific intervals. METHODS: Two thousand seven hundred twenty five apparently healthy adults comprising all ages, both genders and three principal races were recruited through voluntary participation. FBC was performed on two analysers, Sysmex XE-5000 and Unicel DxH 800, in addition to blood smears and haemoglobin analysis. Serum ferritin, soluble transferrin receptor and C-reactive protein assays were performed in selected subjects. All parameters of qualified subjects were tested for normality followed by determination of reference intervals, measures of central tendency and dispersion along with point estimates for each subgroup. RESULTS: Complete data was available in 2440 subjects of whom 56% (907 women and 469 men were included in reference interval calculation. Compared to other populations there were significant differences for haemoglobin, red blood cell count, platelet count and haematocrit in Malaysians. There were differences between men and women, and between younger and older men; unlike in other populations, haemoglobin was similar in younger and older women. However ethnicity and smoking had little impact. 70% of anemia in premenopausal women, 24% in postmenopausal women and 20% of males is attributable to iron deficiency. There was excellent correlation between Sysmex XE-5000 and Unicel DxH 800. CONCLUSION: Our data confirms the importance of population specific haematological parameters and supports the need for local guidelines rather than adoption of generalised reference intervals and cut-offs.

  4. Working Memory Capacity, Confidence and Scientific Thinking

    Science.gov (United States)

    Al-Ahmadi, Fatheya; Oraif, Fatima

    2009-01-01

    Working memory capacity is now well established as a rate determining factor in much learning and assessment, especially in the sciences. Most of the research has focussed on performance in tests and examinations in subject areas. This paper outlines some exploratory work in which other outcomes are related to working memory capacity. Confidence…

  5. Optimal Interval for Repeated Gastric Cancer Screening in Normal-Risk Healthy Korean Adults: A Retrospective Cohort Study.

    Science.gov (United States)

    Bae, Jong-Myon; Shin, Sang Yop; Kim, Eun Hee

    2015-10-01

    This retrospective cohort study was conducted to estimate the optimal interval for gastric cancer screening in Korean adults with initial negative screening results. This study consisted of voluntary Korean screenees aged 40 to 69 years who underwent subsequent screening gastroscopies after testing negative in the baseline screening performed between January 2007 and December 2011. A new case was defined as the presence of gastric cancer cells in biopsy specimens obtained upon gastroscopy. The follow-up periods were calculated during the months between the date of baseline screening gastroscopy and positive findings upon subsequent screenings, stratified by sex and age group. The mean sojourn time (MST) for determining the screening interval was estimated using the prevalence/incidence ratio. Of the 293,520 voluntary screenees for the gastric cancer screening program, 91,850 (31.29%) underwent subsequent screening gastroscopies between January 2007 and December 2011. The MSTs in men and women were 21.67 months (95% confidence intervals [CI], 17.64 to 26.88 months) and 15.14 months (95% CI, 9.44 to 25.85 months), respectively. These findings suggest that the optimal interval for subsequent gastric screening in both men and women is 24 months, supporting the 2-year interval recommended by the nationwide gastric cancer screening program.

  6. Evaluation of Healing Intervals of Incisional Skin Wounds of Goats ...

    African Journals Online (AJOL)

    The aim of this study was to compare the healing intervals among simple interrupted (SI), ford interlocking (FI) and subcuticular (SC) suture patterns in goats. We hypothesized that these common suture patterns used for closure of incisional skin wounds may have effect on the healing interval. To test this hypothesis, two ...

  7. Determination of confidence limits for experiments with low numbers of counts. [Poisson-distributed photon counts from astrophysical sources

    Science.gov (United States)

    Kraft, Ralph P.; Burrows, David N.; Nousek, John A.

    1991-01-01

    Two different methods, classical and Bayesian, for determining confidence intervals involving Poisson-distributed data are compared. Particular consideration is given to cases where the number of counts observed is small and is comparable to the mean number of background counts. Reasons for preferring the Bayesian over the classical method are given. Tables of confidence limits calculated by the Bayesian method are provided for quick reference.

  8. Sources of sport confidence, imagery type and performance among competitive athletes: the mediating role of sports confidence.

    Science.gov (United States)

    Levy, A R; Perry, J; Nicholls, A R; Larkin, D; Davies, J

    2015-01-01

    This study explored the mediating role of sport confidence upon (1) sources of sport confidence-performance relationship and (2) imagery-performance relationship. Participants were 157 competitive athletes who completed state measures of confidence level/sources, imagery type and performance within one hour after competition. Among the current sample, confirmatory factor analysis revealed appropriate support for the nine-factor SSCQ and the five-factor SIQ. Mediational analysis revealed that sport confidence had a mediating influence upon the achievement source of confidence-performance relationship. In addition, both cognitive and motivational imagery types were found to be important sources of confidence, as sport confidence mediated imagery type- performance relationship. Findings indicated that athletes who construed confidence from their own achievements and report multiple images on a more frequent basis are likely to benefit from enhanced levels of state sport confidence and subsequent performance.

  9. Prolongation of Corrected QT Interval Is a Strong Predictor of Arterial Stiffness in Maintenance Hemodialysis Patients: A Prospective Observational Study

    Directory of Open Access Journals (Sweden)

    Zeynep Bal

    2017-03-01

    Full Text Available Background: Rate of mortality due to cardiovascular diseases is high in Maintenance Hemodialysis (MHD patients. Additionally, prolonged QT interval is reportedly associated with high-risk ventricular arrhythmia and sudden death. Vascular calcification may be related to QT dispersion interval in MHD patients because the extensive nature of the calcification process may involve the conducting system and myocardium. Objectives: This study aimed to evaluate the relationship between QT interval and Pulse Wave Velocity (PWV as a sign of arterial stiffness associated with atherosclerosis in MHD patients. Patients and Methods: This prospective, observational study was conducted on 149 eligible MHD patients for 12 months. Patients using drugs known to affect QT interval were excluded. The patients were divided into four groups as follows: normal corrected QT (QTc interval at the beginning and end of the study (n = 44, 29.5%, normal QTc interval at the beginning but prolonged QTc interval at the end of the study (n = 30, 20.1%, prolonged QTc interval at the beginning but normal QTc interval at the end of the study (n = 24, 16.1%, and prolonged QTc interval at the beginning and end of the study (n = 51, 34.2%. Demographic parameters, laboratory parameters, and PWV were assessed at the beginning and the 12th month of the study. Then, the data were analyzed using ANOVA or Pearson 2 test and P < 0.05 was considered to be statistically significant. Results: The study groups were similar with respect to age and comorbidities, including diabetes mellitus, hypertension, and dyslipidemia. In addition, there were no significant differences among the groups regarding the initial PWV (P = 0.412; however, the ending PWV showed significant differences (P = 0.029. The results of multivariate analysis showed that PWV was independently associated with change in the maximum QTc (confidence interval: 0.039 – 1.787, P = 0.031, β = 0.178. Conclusions: The results suggested

  10. Vaccination Confidence and Parental Refusal/Delay of Early Childhood Vaccines.

    Directory of Open Access Journals (Sweden)

    Melissa B Gilkey

    Full Text Available To support efforts to address parental hesitancy towards early childhood vaccination, we sought to validate the Vaccination Confidence Scale using data from a large, population-based sample of U.S. parents.We used weighted data from 9,354 parents who completed the 2011 National Immunization Survey. Parents reported on the immunization history of a 19- to 35-month-old child in their households. Healthcare providers then verified children's vaccination status for vaccines including measles, mumps, and rubella (MMR, varicella, and seasonal flu. We used separate multivariable logistic regression models to assess associations between parents' mean scores on the 8-item Vaccination Confidence Scale and vaccine refusal, vaccine delay, and vaccination status.A substantial minority of parents reported a history of vaccine refusal (15% or delay (27%. Vaccination confidence was negatively associated with refusal of any vaccine (odds ratio [OR] = 0.58, 95% confidence interval [CI], 0.54-0.63 as well as refusal of MMR, varicella, and flu vaccines specifically. Negative associations between vaccination confidence and measures of vaccine delay were more moderate, including delay of any vaccine (OR = 0.81, 95% CI, 0.76-0.86. Vaccination confidence was positively associated with having received vaccines, including MMR (OR = 1.53, 95% CI, 1.40-1.68, varicella (OR = 1.54, 95% CI, 1.42-1.66, and flu vaccines (OR = 1.32, 95% CI, 1.23-1.42.Vaccination confidence was consistently associated with early childhood vaccination behavior across multiple vaccine types. Our findings support expanding the application of the Vaccination Confidence Scale to measure vaccination beliefs among parents of young children.

  11. Evaluation of undergraduate nursing students' clinical confidence following a mental health recovery camp.

    Science.gov (United States)

    Cowley, Thomas; Sumskis, Sue; Moxham, Lorna; Taylor, Ellie; Brighton, Renee; Patterson, Chris; Halcomb, Elizabeth

    2016-02-01

    In the present study, we evaluate the impact of participation in a mental health recovery camp on the clinical confidence of undergraduate nursing students in dealing with individuals with mental illness. Twenty undergraduate nursing students who participated in the recovery camp completed the Mental Health Nursing Clinical Confidence Scale both before and directly after attending the camp. Data were analysed using descriptive and inferential statistics. Participation in the recovery camp was associated with a statistically-significant increase in students' level of overall confidence between the pretest and post-test data (P students over the age of 25 years and who do not have a family history of mental illness are more likely to self-report a higher level of confidence in both the pre- and post-results. The clinical confidence of undergraduate nursing students improved through participation in an immersive clinical experience within the recovery camp. © 2016 Australian College of Mental Health Nurses Inc.

  12. Assessing Residents' Confidence in the Context of Pharmacotherapy Competence.

    Science.gov (United States)

    Rakofsky, Jeffrey J; Garlow, Steven J; Haroon, Ebrahim; Hermida, Adriana P; Young, John Q; Dunlop, Boadie W

    2017-06-01

    We aimed to determine whether residents' confidence initiating medications increased with the number of times they prescribed individual medications and to quantify the relationship between prescription frequency and gains in confidence. From July 2011 to June 2014, PGY-3 residents completed a survey of confidence levels at their psychopharmacology clinic orientation and then again 12 months later. The Emory Healthcare electronic medical record was used to identify all medications prescribed by each resident during their 12-month rotation and the frequency of these prescriptions. Confidence in initiating treatment with all medicines/medication classes increased over the 12-month period. For three of the medication classes for which residents indicated they were least confident at orientation, the number of prescriptions written during the year was significantly associated with an increase in confidence. Measuring resident confidence is a relevant and achievable outcome and provides data for educators regarding the amount of experience needed to increase confidence.

  13. Mathematical Foundations for a Theory of Confidence Structures

    Science.gov (United States)

    Balch, Michael Scott

    2012-01-01

    This paper introduces a new mathematical object: the confidence structure. A confidence structure represents inferential uncertainty in an unknown parameter by defining a belief function whose output is commensurate with Neyman-Pearson confidence. Confidence structures on a group of input variables can be propagated through a function to obtain a valid confidence structure on the output of that function. The theory of confidence structures is created by enhancing the extant theory of confidence distributions with the mathematical generality of Dempster-Shafer evidence theory. Mathematical proofs grounded in random set theory demonstrate the operative properties of confidence structures. The result is a new theory which achieves the holistic goals of Bayesian inference while maintaining the empirical rigor of frequentist inference. PMID:25190904

  14. Alternative confidence measure for local matching stereo algorithms

    CSIR Research Space (South Africa)

    Ndhlovu, T

    2009-11-01

    Full Text Available The authors present a confidence measure applied to individual disparity estimates in local matching stereo correspondence algorithms. It aims at identifying textureless areas, where most local matching algorithms fail. The confidence measure works...

  15. Pre-operative urodynamics in women with stress urinary incontinence increases physician confidence, but does not improve outcomes.

    Science.gov (United States)

    Zimmern, Philippe; Litman, Heather; Nager, Charles; Sirls, Larry; Kraus, Stephen R; Kenton, Kimberly; Wilson, Tracey; Sutkin, Gary; Siddiqui, Nazema; Vasavada, Sandip; Norton, Peggy

    2014-03-01

    To determine if pre-operative urodynamic testing (UDS) affects physicians' diagnostic confidence and if physician confidence affects treatment outcomes at 1 year. The Value of Urodynamic Evaluation (ValUE) trial randomized 630 women with predominant stress urinary incontinence (SUI) to office evaluation (OE) or OE plus UDS prior to surgery. After OE, physicians completed a checklist of five clinical diagnoses: SUI, overactive bladder (OAB) wet and dry, voiding dysfunction (VD), and intrinsic sphincter deficiency (ISD), and reported their confidence in each. Responses ranged from 1 to 5 with; 1 = "not very confident (confident (95 + %)." After UDS, investigators again rated their confidence in these five clinical diagnoses. Logistic regression analysis correlated physician confidence in diagnosis with treatment success. Of 315 women who received OE plus UDS, 294 had complete data. Confidence improved after UDS in patients with baseline SUI (4.52-4.63, P confidence after UDS was not associated with higher odds of treatment success although mean changes in confidence were slightly higher for those who achieved treatment success. Physician diagnoses shifted more from not confident to confident for ISD and OAB-wet after UDS (McNemar's P-value women undergoing UDS for predominant SUI, UDS increased physicians' confidence in their clinical diagnoses; however, this did not correlate with treatment success. © 2013 Wiley Periodicals, Inc.

  16. Pediatric reference intervals for lymphocyte vitamin C (ascorbic acid).

    Science.gov (United States)

    Levin, Alex; DeSouza, Charmaine; Zaarour, Christian; Walsh, Warren; Chan, Man Khun; Verjee, Zulfikarali; McIntyre, Susan; Adeli, Khosrow

    2010-12-01

    To establish pediatric reference intervals for lymphocyte vitamin C. This was a prospective study of 194 well children aged 0-7 years old of mixed ethnicity who had blood drawn for the purpose of this study. Blood was collected during elective surgery under general anesthesia and lymphocytes isolated and stored as frozen ascorbic acid lymphocyte lysates for later HPLC analysis by previously described methodology. Reference intervals were established according to the Clinical and Laboratory Standards Institute (CLSI) and the International Federation of Clinical Chemistry (IFCC) guidelines (C28-A3). Horn-Pesce robust method was used to estimate the 95% confidence interval and 95% reference interval. Reference intervals were independent of age or gender and shown to be 12.9-52.8 μg/10(8) cells (lymphocytes). We have defined pediatric reference ranges for lymphocyte vitamin C in healthy, fasted children at a relevant age group (0-7 years). The new reference interval can now be used to more reliably explore possible implications of variation of vitamin C levels on bleeding and other clinical signs. Copyright © 2010 Elsevier Inc. All rights reserved.

  17. Improving Quality Using Architecture Fault Analysis with Confidence Arguments

    Science.gov (United States)

    2015-03-01

    Improving Quality Using Architecture Fault Analysis with Confidence Arguments Peter H. Feiler Charles B. Weinstock John B. Goodenough...Design 8 2.3 Architecture Fault Modeling and Analysis with EMV2 8 2.4 Confidence Map Concepts and Notation 11 Overview of the Stepper-Motor System...Comparison of the SMS Designs 43 Establishing Confidence in the SMS 45 6.1 Confidence Maps for SMS 45 CMU/SEI-2015-TR-006 | SOFTWARE ENGINEERING

  18. 21 CFR 26.37 - Confidence building activities.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Confidence building activities. 26.37 Section 26... COMMUNITY Specific Sector Provisions for Medical Devices § 26.37 Confidence building activities. (a) At the beginning of the transitional period, the Joint Sectoral Group will establish a joint confidence building...

  19. 7 CFR 97.18 - Applications handled in confidence.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Applications handled in confidence. 97.18 Section 97.18 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING... confidence. (a) Pending applications shall be handled in confidence. Except as provided below, no information...

  20. Opinion formation with time-varying bounded confidence.

    Science.gov (United States)

    Zhang, YunHong; Liu, QiPeng; Zhang, SiYing

    2017-01-01

    When individuals in social groups communicate with one another and are under the influence of neighbors' opinions, they typically revise their own opinions to adapt to such peer opinions. The individual threshold of bounded confidence will thus be affected by both a change in individual confidence and by neighbor influence. Individuals thus update their own opinions with new bounded confidence, while their updated opinions also influence their neighbors' opinions. Based on this reasoned factual assumption, we propose an opinion dynamics model with time-varying bounded confidence. A directed network is formed by the rule of the individual bounded confidence threshold. The threshold of individual bounded confidence involves both confidence variation and the in/out degree of the individual node. When the confidence variation is greater, an individual's confidence in persisting in his own opinion in interactions is weaker, and the individual is more likely to adopt neighbors' opinions. In networks, the in/out degree is determined by individual neighbors. Our main research involves the process of opinion evolution and the basic laws of opinion cluster formation. Group opinions converge exponentially to consensus with stable neighbors. An individual opinion evolution is determined by the average neighbor opinion effect strength. We also explore the conditions involved in forming a stable neighbor relationship and the influence of the confidence variation in the convergence of the threshold of bounded confidence. The results show that the influence on opinion evolution is greater with increased confidence variation.

  1. 49 CFR 1103.23 - Confidences of a client.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Confidences of a client. 1103.23 Section 1103.23... Responsibilities Toward A Client § 1103.23 Confidences of a client. (a) The practitioner's duty to preserve his client's confidence outlasts the practitioner's employment by the client, and this duty extends to the...

  2. Contrasting Academic Behavioural Confidence in Mexican and European Psychology Students

    Science.gov (United States)

    Ochoa, Alma Rosa Aguila; Sander, Paul

    2012-01-01

    Introduction: Research with the Academic Behavioural Confidence scale using European students has shown that students have high levels of confidence in their academic abilities. It is generally accepted that people in more collectivist cultures have more realistic confidence levels in contrast to the overconfidence seen in individualistic European…

  3. A new method of sweat testing: the CF Quantum®sweat test.

    Science.gov (United States)

    Rock, Michael J; Makholm, Linda; Eickhoff, Jens

    2014-09-01

    Conventional methods of sweat testing are time consuming and have many steps that can and do lead to errors. This study compares conventional sweat testing to a new quantitative method, the CF Quantum® (CFQT) sweat test. This study tests the diagnostic accuracy and analytic validity of the CFQT. Previously diagnosed CF patients and patients who required a sweat test for clinical indications were invited to have the CFQT test performed. Both conventional sweat testing and the CFQT were performed bilaterally on the same day. Pairs of data from each test are plotted as a correlation graph and Bland-Altman plot. Sensitivity and specificity were calculated as well as the means and coefficient of variation by test and by extremity. After completing the study, subjects or their parents were asked for their preference of the CFQT and conventional sweat testing. The correlation coefficient between the CFQT and conventional sweat testing was 0.98 (95% confidence interval: 0.97-0.99). The sensitivity and specificity of the CFQT in diagnosing CF was 100% (95% confidence interval: 94-100%) and 96% (95% confidence interval: 89-99%), respectively. In one center in this three center multicenter study, there were higher sweat chloride values in patients with CF and also more tests that were invalid due to discrepant values between the two extremities. The percentage of invalid tests was higher in the CFQT method (16.5%) compared to conventional sweat testing (3.8%) (p sweat chloride determination. This technology requires further refinement to improve the analytic accuracy at higher sweat chloride values and to decrease the number of invalid tests. Copyright © 2014 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  4. INTERVAL OBJECTS AND THEIR GRAMMATICAL STRUCTURE

    Directory of Open Access Journals (Sweden)

    V. M. Ilman

    2009-09-01

    Full Text Available In the article the structures of free interval objects and formal interval grammar are constructed. The grammar structure takes into account the condition of interval compatibility in the chain constructions of language generated.

  5. Performance of a rapid self-test for detection of Trichomonas vaginalis in South Africa and Brazil

    NARCIS (Netherlands)

    Jones, Heidi E.; Lippman, Sheri A.; Caiaffa-Filho, Helio H.; Young, Taryn; van de Wijgert, Janneke H. H. M.

    2013-01-01

    Women participating in studies in Brazil (n = 695) and South Africa (n = 230) performed rapid point-of-care tests for Trichomonas vaginalis on self-collected vaginal swabs. Using PCR as the gold standard, rapid self-testing achieved high specificity (99.1%; 95% confidence interval [CI], 98.2 to

  6. Feature Augmentation for Learning Confidence Measure in Stereo Matching.

    Science.gov (United States)

    Kim, Sunok; Min, Dongbo; Kim, Seungryong; Sohn, Kwanghoon

    2017-09-08

    Confidence estimation is essential for refining stereo matching results through a post-processing step. This problem has recently been studied using a learning-based approach, which demonstrates a substantial improvement on conventional simple non-learning based methods. However, the formulation of learning-based methods that individually estimates the confidence of each pixel disregards spatial coherency that might exist in the confidence map, thus providing a limited performance under challenging conditions. Our key observation is that the confidence features and resulting confidence maps are smoothly varying in the spatial domain, and highly correlated within the local regions of an image. We present a new approach that imposes spatial consistency on the confidence estimation. Specifically, a set of robust confidence features is extracted from each superpixel decomposed using the Gaussian mixture model (GMM), and then these features are concatenated with pixel-level confidence features. The features are then enhanced through adaptive filtering in the feature domain. In addition, the resulting confidence map, estimated using the confidence features with a random regression forest, is further improved through K-nearest neighbor (K-NN) based aggregation scheme on both pixel-and superpixel-level. To validate the proposed confidence estimation scheme, we employ cost modulation or ground control points (GCPs) based optimization in stereo matching. Experimental results demonstrate that the proposed method outperforms state-of-the-art approaches on various benchmarks including challenging outdoor scenes.

  7. Relating confidence to information uncertainty in qualitative reasoning

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, Gregory M [Los Alamos National Laboratory; Zerkle, David K [Los Alamos National Laboratory; Key, Brian P [Los Alamos National Laboratory; Shevitz, Daniel W [Los Alamos National Laboratory

    2010-12-02

    Qualitative reasoning makes use of qualitative assessments provided by subject matter experts to model factors such as security risk. Confidence in a result is important and useful when comparing competing security risk results. Quantifying the confidence in an evidential reasoning result must be consistent and based on the available information. A novel method is proposed to determine a qualitative measure of confidence in a qualitative reasoning result from the available information uncertainty in the result using membership values in the fuzzy sets of confidence. In this study information uncertainty is quantified through measures of non-specificity and conflict. Fuzzy values for confidence are established from information uncertainty values that lie between the measured minimum and maximum information uncertainty values. Measured values of information uncertainty in each result is used to obtain the confidence. The determined confidence values are used to compare competing scenarios and understand the influences on the desired result.

  8. Temporal control mechanism in equaled interval tapping.

    Science.gov (United States)

    Yamada, M

    1996-05-01

    Subjects who were at intermediate levels of musical performance made equaled interval tapping in several tempos. The temporal fluctuation for the tapping was observed and analysed. The power spectrum of the fluctuation showed a critical phenomenon at around a frequency which corresponds to the period of 20 taps, for all tempos and all subjects, i.e., the slope of the spectrum was flat or had a positive value in the high frequency region above the critical frequency but it increased as the frequency decreased in the low frequency region below the critical frequency. Moreover, auto-regressive models and Akaike's information criterion were introduced to determine the critical tap number. The order of the best auto-regressive model for the temporal fluctuation data was distributed around 20 taps. These results show that the memory capacity of 20 taps governs the control of equaled interval tapping. To interpret the critical phenomenon of 20 taps with the memory capacity of the short term memory, the so called magic number seven, a simple chunking assumption was introduced; subjects might have unconsciously chunked every three taps during the tapping. If the chunking assumption is true, when subjects consciously chunk every seven taps, the memory capacity of taps should shift to about 50 taps. To test if the assumption is true or not, subjects made a three-beat rhythm tapping and a seven-beat rhythm tapping with equaled intervals. As a result, the memory capacity for these accented tappings were also estimated as 20 taps. This suggests that the critical phenomenon cannot be explained by the chunking assumption and the magic number seven, rather this finding suggests that there exists a memory capacity of 20 taps and this is used for equaled interval tapping.

  9. Validating a self-confidence scale for surgical trainees.

    Science.gov (United States)

    Geoffrion, Roxana; Lee, Terry; Singer, Joel

    2013-04-01

    Self-confidence is a feeling of trust in one's abilities, qualities, and judgement. It is one of the cognitive mechanisms underlying behavioural change. Variations in self-confidence influence motivation and predict performance success. We sought to validate a new tool for measuring self-confidence in surgical residents. A self-confidence rating scale was developed and consisted of six questions about the attitudes of gynaecology residents while performing a vaginal hysterectomy. The residents were participants in a randomized controlled trial (2008 to 2011) and performed a vaginal hysterectomy before and after an educational intervention. They rated their own surgical performance on a validated global rating scale (GRS) of surgical skill and their self-confidence on the new rating scale. Supervising surgeons concurrently rated the residents' performance on the GRS. Correlations were sought between self-confidence scale scores and measures of competence. There was no difference in self-confidence scores between intervention and control residents at baseline. The number of vaginal hysterectomies performed before the educational intervention was associated with a significantly higher confidence level (P = 0.024). Other demographic variables such as age and gender did not influence confidence levels. Internal consistency between the individual scale items was good (Cronbach alpha 0.85). Self-confidence scores were significantly higher after the educational intervention (P = 0.04). Self-confidence was positively correlated with both self-assessed and supervising-surgeon-assessed GRS scores in both intervention and control residents. The self-confidence scale is a psychometrically valid tool to measure residents' self-confidence during surgical learning. More research is needed to establish the role of this scale for feedback, to channel self-confidence, and to optimize surgical skill acquisition.

  10. Variational collocation on finite intervals

    Energy Technology Data Exchange (ETDEWEB)

    Amore, Paolo [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Colima, Colima (Mexico); Cervantes, Mayra [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Colima, Colima (Mexico); Fernandez, Francisco M [INIFTA (Conicet, UNLP), Diag. 113 y 64 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)

    2007-10-26

    In this paper, we study a set of functions, defined on an interval of finite width, which are orthogonal and which reduce to the sinc functions when the appropriate limit is taken. We show that these functions can be used within a variational approach to obtain accurate results for a variety of problems. We have applied them to the interpolation of functions on finite domains and to the solution of the Schroedinger equation, and we have compared the performance of the present approach with others.

  11. Dijets at large rapidity intervals

    CERN Document Server

    Pope, B G

    2001-01-01

    Inclusive diet production at large pseudorapidity intervals ( Delta eta ) between the two jets has been suggested as a regime for observing BFKL dynamics. We have measured the dijet cross section for large Delta eta in pp collisions at square root s = 1800 and 630 GeV using the DOE detector. The partonic cross section increases strongly with the size of Delta eta . The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alpha /sub BFKL/(20 GeV) = 1.65 +or- 0.07.

  12. Updating metacognitive control in response to expected retention intervals.

    Science.gov (United States)

    Fiechter, Joshua L; Benjamin, Aaron S

    2017-04-01

    In five experiments, we investigated whether expected retention intervals affect subjects' encoding strategies. In the first four experiments, our subjects studied paired associates consisting of words from the Graduate Record Exam and a synonym. They were told to expect a test on a word pair after either a short or a longer interval. Subjects were tested on most pairs after the expected retention interval. For some pairs, however, subjects were tested after the other retention interval, allowing for a comparison of performance at a given retention interval conditional upon the expected retention interval. No effect of the expected retention interval was found for 1 min versus 4 min (Exp. 1), 30 s versus 3 min (Exp. 2), and 30 s versus 10 min (Exps. 3 and 4), even when subjects were given complete control over the pacing of study items (Exp. 4). However, when the difference between the expected retention intervals was increased massively (10 min vs. 24 h; Exp. 5), subjects remembered more items that they expected to be tested sooner, an effect consistent with the idea that they traded off efforts to remember items for the later test versus items that were about to be tested. Overall, this set of results accords with much of the test-expectancy literature, revealing that subjects are often reluctant to adjust encoding strategies on an item-by-item basis, and when they do, they usually make quantitative, rather than qualitative, adjustments.

  13. Self-Confidence and Paranoia: An Experimental Study Using an Immersive Virtual Reality Social Situation.

    Science.gov (United States)

    Atherton, Stephanie; Antley, Angus; Evans, Nicole; Cernis, Emma; Lister, Rachel; Dunn, Graham; Slater, Mel; Freeman, Daniel

    2016-01-01

    Paranoia may build directly upon negative thoughts about the self. There have been few direct experimental tests of this hypothesis. The aim of the study was to test the immediate effects of manipulating self-esteem in individuals vulnerable to paranoia. A two condition cross-over experimental test was conducted. The participants were 26 males reporting paranoid ideation in the past month. Each participant experienced a neutral immersive virtual reality (VR) social environment twice. Before VR participants received a low self-confidence manipulation or a high self-confidence manipulation. The order of manipulation type was randomized. Paranoia about the VR avatars was assessed. The low self-confidence manipulation, relative to the high self-confidence manipulation, led to significantly more negative social comparison in virtual reality and higher levels of paranoia. Level of self-confidence affects the occurrence of paranoia in vulnerable individuals. The clinical implication is that interventions designed to improve self-confidence may reduce persecutory ideation.

  14. "Yes, we can!" review on team confidence in sports.

    Science.gov (United States)

    Fransen, Katrien; Mertens, Niels; Feltz, Deborah; Boen, Filip

    2017-08-01

    During the last decade, team confidence has received more and more attention in the sport psychology literature. Research has demonstrated that athletes who are more confident in their team's abilities exert more effort, set more challenging goals, are more resilient when facing adversities, and ultimately perform better. This article reviews the existing literature in order to provide more clarity in terms of the conceptualization and the operationalization of team confidence. We thereby distinguish between collective efficacy (i.e., process-oriented team confidence) and team outcome confidence (i.e., outcome-oriented team confidence). In addition, both the sources as well as the outcomes of team confidence will be discussed. Furthermore, we will go deeper into the dispersion of team confidence and we will evaluate the current guidelines on how to measure both types of team confidence. Building upon this base, the article then highlights interesting avenues for future research in order to further improve both our theoretical knowledge on team confidence and its application to the field. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Oxygen Uptake in Maximal Effort Constant Rate and Interval Running

    Directory of Open Access Journals (Sweden)

    Daniel Pratt

    2013-01-01

    Full Text Available This study investigated differences in average of maximal effort interval running to maximal effort constant rate running at lactate threshold matched for time. The average and distance covered of 10 recreational male runners (: 4158 ± 390 mL·min−1 were compared between a maximal effort constant-rate run at lactate threshold (CRLT, a maximal effort interval run (INT consisting of 2 min at speed with 2 minutes at 50% of repeated 5 times, and a run at the average speed sustained during the interval run (CR submax. Data are presented as mean and 95% confidence intervals. The average for INT, 3451 (3269–3633 mL·min−1, 83% , was not significantly different to CRLT, 3464 (3285–3643 mL·min−1, 84% , but both were significantly higher than CR sub-max, 3464 (3285–3643 mL·min−1, 76% . The distance covered was significantly greater in CLRT, 4431 (4202–3731 metres, compared to INT and CR sub-max, 4070 (3831–4309 metres. The novel finding was that a 20-minute maximal effort constant rate run uses similar amounts of oxygen as a 20-minute maximal effort interval run despite the greater distance covered in the maximal effort constant-rate run.

  16. Test

    DEFF Research Database (Denmark)

    Bendixen, Carsten

    2014-01-01

    Bidrag med en kortfattet, introducerende, perspektiverende og begrebsafklarende fremstilling af begrebet test i det pædagogiske univers.......Bidrag med en kortfattet, introducerende, perspektiverende og begrebsafklarende fremstilling af begrebet test i det pædagogiske univers....

  17. Interval Estimators of the Centre and Width of a Two-Dimensional Microstructure

    Science.gov (United States)

    Wimmer, G.; Karovič, K.

    2009-01-01

    In metrology it is used to estimate the stipulated quantity as a mean and its uncertainty. This procedure is legitimate when the evaluated data are symmetrically distributed and the distribution is (at least approximately) known. But there exist many evaluating treatments in which the evaluated values are non-symmetrically distributed. In this case it is mathematically correct to use an interval estimator for the stipulated (measured) quantity i.e. to evaluate the (1-α)-confidence interval for the (true) stipulated (measured) quantity. This (random) interval covers with probability 1-α the (true) stipulated quantity. In the paper are presented interval estimators for some parameters of two-dimensional structures.

  18. Reference Value Advisor: a new freeware set of macroinstructions to calculate reference intervals with Microsoft Excel.

    Science.gov (United States)

    Geffré, Anne; Concordet, Didier; Braun, Jean-Pierre; Trumel, Catherine

    2011-03-01

    International recommendations for determination of reference intervals have been recently updated, especially for small reference sample groups, and use of the robust method and Box-Cox transformation is now recommended. Unfortunately, these methods are not included in most software programs used for data analysis by clinical laboratories. We have created a set of macroinstructions, named Reference Value Advisor, for use in Microsoft Excel to calculate reference limits applying different methods. For any series of data, Reference Value Advisor calculates reference limits (with 90% confidence intervals [CI]) using a nonparametric method when n≥40 and by parametric and robust methods from native and Box-Cox transformed values; tests normality of distributions using the Anderson-Darling test and outliers using Tukey and Dixon-Reed tests; displays the distribution of values in dot plots and histograms and constructs Q-Q plots for visual inspection of normality; and provides minimal guidelines in the form of comments based on international recommendations. The critical steps in determination of reference intervals are correct selection of as many reference individuals as possible and analysis of specimens in controlled preanalytical and analytical conditions. Computing tools cannot compensate for flaws in selection and size of the reference sample group and handling and analysis of samples. However, if those steps are performed properly, Reference Value Advisor, available as freeware at http://www.biostat.envt.fr/spip/spip.php?article63, permits rapid assessment and comparison of results calculated using different methods, including currently unavailable methods. This allows for selection of the most appropriate method, especially as the program provides the CI of limits. It should be useful in veterinary clinical pathology when only small reference sample groups are available. ©2011 American Society for Veterinary Clinical Pathology.

  19. Some Characterizations of Convex Interval Games

    NARCIS (Netherlands)

    Brânzei, R.; Tijs, S.H.; Alparslan-Gok, S.Z.

    2008-01-01

    This paper focuses on new characterizations of convex interval games using the notions of exactness and superadditivity. We also relate big boss interval games with concave interval games and obtain characterizations of big boss interval games in terms of exactness and subadditivity.

  20. Evidence for a confidence-accuracy relationship in memory for same- and cross-race faces.

    Science.gov (United States)

    Nguyen, Thao B; Pezdek, Kathy; Wixted, John T

    2017-12-01

    Discrimination accuracy is usually higher for same- than for cross-race faces, a phenomenon known as the cross-race effect (CRE). According to prior research, the CRE occurs because memories for same- and cross-race faces rely on qualitatively different processes. However, according to a continuous dual-process model of recognition memory, memories that rely on qualitatively different processes do not differ in recognition accuracy when confidence is equated. Thus, although there are differences in overall same- and cross-race discrimination accuracy, confidence-specific accuracy (i.e., recognition accuracy at a particular level of confidence) may not differ. We analysed datasets from four recognition memory studies on same- and cross-race faces to test this hypothesis. Confidence ratings reliably predicted recognition accuracy when performance was above chance levels (Experiments 1, 2, and 3) but not when performance was at chance levels (Experiment 4). Furthermore, at each level of confidence, confidence-specific accuracy for same- and cross-race faces did not significantly differ when overall performance was above chance levels (Experiments 1, 2, and 3) but significantly differed when overall performance was at chance levels (Experiment 4). Thus, under certain conditions, high-confidence same-race and cross-race identifications may be equally reliable.