Paternal education status significantly influences infants’ measles vaccination uptake, independent of maternal education status

Directory of Open Access Journals (Sweden)

Rammohan Anu

2012-07-01

Full Text Available Abstract Background Despite increased funding of measles vaccination programs by national governments and international aid agencies, structural factors encumber attainment of childhood measles immunisation to levels which may guarantee herd immunity. One of such factors is parental education status. Research on the links between parental education and vaccination has typically focused on the influence of maternal education status. This study aims to demonstrate the independent influence of paternal education status on measles immunisation. Methods Comparable nationally representative survey data were obtained from six countries with the highest numbers of children missing the measles vaccine in 2008. Logistic regression analysis was applied to examine the influence of paternal education on uptake of the first dose of measles vaccination, independent of maternal education, whilst controlling for confounding factors such as respondent’s age, urban/rural residence, province/state of residence, religion, wealth and occupation. Results The results of the analysis show that even if a mother is illiterate, having a father with an education of Secondary (high school schooling and above is statistically significant and positively correlated with the likelihood of a child being vaccinated for measles, in the six countries analysed. Paternal education of secondary or higher level was significantly and independently correlated with measles immunisation uptake after controlling for all potential confounders. Conclusions The influence of paternal education status on measles immunisation uptake was investigated and found to be statistically significant in six nations with the biggest gaps in measles immunisation coverage in 2008. This study underscores the imperative of utilising both maternal and paternal education as screening variables to identify children at risk of missing measles vaccination prospectively.

Paternal education status significantly influences infants’ measles vaccination uptake, independent of maternal education status

Science.gov (United States)

2012-01-01

Background Despite increased funding of measles vaccination programs by national governments and international aid agencies, structural factors encumber attainment of childhood measles immunisation to levels which may guarantee herd immunity. One of such factors is parental education status. Research on the links between parental education and vaccination has typically focused on the influence of maternal education status. This study aims to demonstrate the independent influence of paternal education status on measles immunisation. Methods Comparable nationally representative survey data were obtained from six countries with the highest numbers of children missing the measles vaccine in 2008. Logistic regression analysis was applied to examine the influence of paternal education on uptake of the first dose of measles vaccination, independent of maternal education, whilst controlling for confounding factors such as respondent’s age, urban/rural residence, province/state of residence, religion, wealth and occupation. Results The results of the analysis show that even if a mother is illiterate, having a father with an education of Secondary (high school) schooling and above is statistically significant and positively correlated with the likelihood of a child being vaccinated for measles, in the six countries analysed. Paternal education of secondary or higher level was significantly and independently correlated with measles immunisation uptake after controlling for all potential confounders. Conclusions The influence of paternal education status on measles immunisation uptake was investigated and found to be statistically significant in six nations with the biggest gaps in measles immunisation coverage in 2008. This study underscores the imperative of utilising both maternal and paternal education as screening variables to identify children at risk of missing measles vaccination prospectively. PMID:22568861

Statistical Significance for Hierarchical Clustering

Science.gov (United States)

Kimes, Patrick K.; Liu, Yufeng; Hayes, D. Neil; Marron, J. S.

2017-01-01

Summary Cluster analysis has proved to be an invaluable tool for the exploratory and unsupervised analysis of high dimensional datasets. Among methods for clustering, hierarchical approaches have enjoyed substantial popularity in genomics and other fields for their ability to simultaneously uncover multiple layers of clustering structure. A critical and challenging question in cluster analysis is whether the identified clusters represent important underlying structure or are artifacts of natural sampling variation. Few approaches have been proposed for addressing this problem in the context of hierarchical clustering, for which the problem is further complicated by the natural tree structure of the partition, and the multiplicity of tests required to parse the layers of nested clusters. In this paper, we propose a Monte Carlo based approach for testing statistical significance in hierarchical clustering which addresses these issues. The approach is implemented as a sequential testing procedure guaranteeing control of the family-wise error rate. Theoretical justification is provided for our approach, and its power to detect true clustering structure is illustrated through several simulation studies and applications to two cancer gene expression datasets. PMID:28099990

Statistical significance of trends in monthly heavy precipitation over the US

KAUST Repository

Mahajan, Salil

2011-05-11

Trends in monthly heavy precipitation, defined by a return period of one year, are assessed for statistical significance in observations and Global Climate Model (GCM) simulations over the contiguous United States using Monte Carlo non-parametric and parametric bootstrapping techniques. The results from the two Monte Carlo approaches are found to be similar to each other, and also to the traditional non-parametric Kendall\\'s τ test, implying the robustness of the approach. Two different observational data-sets are employed to test for trends in monthly heavy precipitation and are found to exhibit consistent results. Both data-sets demonstrate upward trends, one of which is found to be statistically significant at the 95% confidence level. Upward trends similar to observations are observed in some climate model simulations of the twentieth century, but their statistical significance is marginal. For projections of the twenty-first century, a statistically significant upwards trend is observed in most of the climate models analyzed. The change in the simulated precipitation variance appears to be more important in the twenty-first century projections than changes in the mean precipitation. Stochastic fluctuations of the climate-system are found to be dominate monthly heavy precipitation as some GCM simulations show a downwards trend even in the twenty-first century projections when the greenhouse gas forcings are strong. © 2011 Springer-Verlag.

Sibling Competition & Growth Tradeoffs. Biological vs. Statistical Significance.

Science.gov (United States)

Kramer, Karen L; Veile, Amanda; Otárola-Castillo, Erik

2016-01-01

Early childhood growth has many downstream effects on future health and reproduction and is an important measure of offspring quality. While a tradeoff between family size and child growth outcomes is theoretically predicted in high-fertility societies, empirical evidence is mixed. This is often attributed to phenotypic variation in parental condition. However, inconsistent study results may also arise because family size confounds the potentially differential effects that older and younger siblings can have on young children's growth. Additionally, inconsistent results might reflect that the biological significance associated with different growth trajectories is poorly understood. This paper addresses these concerns by tracking children's monthly gains in height and weight from weaning to age five in a high fertility Maya community. We predict that: 1) as an aggregate measure family size will not have a major impact on child growth during the post weaning period; 2) competition from young siblings will negatively impact child growth during the post weaning period; 3) however because of their economic value, older siblings will have a negligible effect on young children's growth. Accounting for parental condition, we use linear mixed models to evaluate the effects that family size, younger and older siblings have on children's growth. Congruent with our expectations, it is younger siblings who have the most detrimental effect on children's growth. While we find statistical evidence of a quantity/quality tradeoff effect, the biological significance of these results is negligible in early childhood. Our findings help to resolve why quantity/quality studies have had inconsistent results by showing that sibling competition varies with sibling age composition, not just family size, and that biological significance is distinct from statistical significance.

Sibling Competition & Growth Tradeoffs. Biological vs. Statistical Significance.

Directory of Open Access Journals (Sweden)

Karen L Kramer

Full Text Available Early childhood growth has many downstream effects on future health and reproduction and is an important measure of offspring quality. While a tradeoff between family size and child growth outcomes is theoretically predicted in high-fertility societies, empirical evidence is mixed. This is often attributed to phenotypic variation in parental condition. However, inconsistent study results may also arise because family size confounds the potentially differential effects that older and younger siblings can have on young children's growth. Additionally, inconsistent results might reflect that the biological significance associated with different growth trajectories is poorly understood. This paper addresses these concerns by tracking children's monthly gains in height and weight from weaning to age five in a high fertility Maya community. We predict that: 1 as an aggregate measure family size will not have a major impact on child growth during the post weaning period; 2 competition from young siblings will negatively impact child growth during the post weaning period; 3 however because of their economic value, older siblings will have a negligible effect on young children's growth. Accounting for parental condition, we use linear mixed models to evaluate the effects that family size, younger and older siblings have on children's growth. Congruent with our expectations, it is younger siblings who have the most detrimental effect on children's growth. While we find statistical evidence of a quantity/quality tradeoff effect, the biological significance of these results is negligible in early childhood. Our findings help to resolve why quantity/quality studies have had inconsistent results by showing that sibling competition varies with sibling age composition, not just family size, and that biological significance is distinct from statistical significance.

Increasing the statistical significance of entanglement detection in experiments

Energy Technology Data Exchange (ETDEWEB)

Jungnitsch, Bastian; Niekamp, Soenke; Kleinmann, Matthias; Guehne, Otfried [Institut fuer Quantenoptik und Quanteninformation, Innsbruck (Austria); Lu, He; Gao, Wei-Bo; Chen, Zeng-Bing [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei (China); Chen, Yu-Ao; Pan, Jian-Wei [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei (China); Physikalisches Institut, Universitaet Heidelberg (Germany)

2010-07-01

Entanglement is often verified by a violation of an inequality like a Bell inequality or an entanglement witness. Considerable effort has been devoted to the optimization of such inequalities in order to obtain a high violation. We demonstrate theoretically and experimentally that such an optimization does not necessarily lead to a better entanglement test, if the statistical error is taken into account. Theoretically, we show for different error models that reducing the violation of an inequality can improve the significance. We show this to be the case for an error model in which the variance of an observable is interpreted as its error and for the standard error model in photonic experiments. Specifically, we demonstrate that the Mermin inequality yields a Bell test which is statistically more significant than the Ardehali inequality in the case of a photonic four-qubit state that is close to a GHZ state. Experimentally, we observe this phenomenon in a four-photon experiment, testing the above inequalities for different levels of noise.

Reporting effect sizes as a supplement to statistical significance ...

African Journals Online (AJOL)

The purpose of the article is to review the statistical significance reporting practices in reading instruction studies and to provide guidelines for when to calculate and report effect sizes in educational research. A review of six readily accessible (online) and accredited journals publishing research on reading instruction ...

Your Chi-Square Test Is Statistically Significant: Now What?

Science.gov (United States)

Sharpe, Donald

2015-01-01

Applied researchers have employed chi-square tests for more than one hundred years. This paper addresses the question of how one should follow a statistically significant chi-square test result in order to determine the source of that result. Four approaches were evaluated: calculating residuals, comparing cells, ransacking, and partitioning. Data…

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.

Influence of Signal and Noise on Statistical Fluctuation of Single-Mode Laser System

International Nuclear Information System (INIS)

Xu Dahai; Cheng Qinghua; Cao Li; Wu Dajin

2006-01-01

On the basis of calculating the steady-state mean normalized intensity fluctuation of a signal-mode laser system driven by both colored pump noise with signal modulation and the quantum noise with cross-correlation between its real and imaginary parts, we analyze the influence of modulation signal, noise, and its correlation form on the statistical fluctuation of the laser system. We have found that when the amplitude of modulation signal weakens and its frequency quickens, the statistical fluctuation will reduce rapidly. The statistical fluctuation of the laser system can be restrained by reducing the intensity of pump noise and quantum noise. Moreover, with prolonging of colored cross-correlation time, the statistical fluctuation of laser system experiences a repeated changing process, that is, from decreasing to augmenting, then to decreasing, and finally to augmenting again. With the decreasing of the value of cross-correlation coefficient, the statistical fluctuation will decrease too. When the cross-correlation form between the real part and imaginary part of quantum noise is zero correlation, the statistical fluctuation of laser system has a minimum. Compared with the influence of intensity of pump noise, the influence of intensity of quantum noise on the statistical fluctuation is smaller.

Testing statistical significance scores of sequence comparison methods with structure similarity

Directory of Open Access Journals (Sweden)

Leunissen Jack AM

2006-10-01

Full Text Available Abstract Background In the past years the Smith-Waterman sequence comparison algorithm has gained popularity due to improved implementations and rapidly increasing computing power. However, the quality and sensitivity of a database search is not only determined by the algorithm but also by the statistical significance testing for an alignment. The e-value is the most commonly used statistical validation method for sequence database searching. The CluSTr database and the Protein World database have been created using an alternative statistical significance test: a Z-score based on Monte-Carlo statistics. Several papers have described the superiority of the Z-score as compared to the e-value, using simulated data. We were interested if this could be validated when applied to existing, evolutionary related protein sequences. Results All experiments are performed on the ASTRAL SCOP database. The Smith-Waterman sequence comparison algorithm with both e-value and Z-score statistics is evaluated, using ROC, CVE and AP measures. The BLAST and FASTA algorithms are used as reference. We find that two out of three Smith-Waterman implementations with e-value are better at predicting structural similarities between proteins than the Smith-Waterman implementation with Z-score. SSEARCH especially has very high scores. Conclusion The compute intensive Z-score does not have a clear advantage over the e-value. The Smith-Waterman implementations give generally better results than their heuristic counterparts. We recommend using the SSEARCH algorithm combined with e-values for pairwise sequence comparisons.

Statistical significance versus clinical relevance.

Science.gov (United States)

van Rijn, Marieke H C; Bech, Anneke; Bouyer, Jean; van den Brand, Jan A J G

2017-04-01

In March this year, the American Statistical Association (ASA) posted a statement on the correct use of P-values, in response to a growing concern that the P-value is commonly misused and misinterpreted. We aim to translate these warnings given by the ASA into a language more easily understood by clinicians and researchers without a deep background in statistics. Moreover, we intend to illustrate the limitations of P-values, even when used and interpreted correctly, and bring more attention to the clinical relevance of study findings using two recently reported studies as examples. We argue that P-values are often misinterpreted. A common mistake is saying that P < 0.05 means that the null hypothesis is false, and P ≥0.05 means that the null hypothesis is true. The correct interpretation of a P-value of 0.05 is that if the null hypothesis were indeed true, a similar or more extreme result would occur 5% of the times upon repeating the study in a similar sample. In other words, the P-value informs about the likelihood of the data given the null hypothesis and not the other way around. A possible alternative related to the P-value is the confidence interval (CI). It provides more information on the magnitude of an effect and the imprecision with which that effect was estimated. However, there is no magic bullet to replace P-values and stop erroneous interpretation of scientific results. Scientists and readers alike should make themselves familiar with the correct, nuanced interpretation of statistical tests, P-values and CIs. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Statistical significance of epidemiological data. Seminar: Evaluation of epidemiological studies

International Nuclear Information System (INIS)

Weber, K.H.

1993-01-01

In stochastic damages, the numbers of events, e.g. the persons who are affected by or have died of cancer, and thus the relative frequencies (incidence or mortality) are binomially distributed random variables. Their statistical fluctuations can be characterized by confidence intervals. For epidemiologic questions, especially for the analysis of stochastic damages in the low dose range, the following issues are interesting: - Is a sample (a group of persons) with a definite observed damage frequency part of the whole population? - Is an observed frequency difference between two groups of persons random or statistically significant? - Is an observed increase or decrease of the frequencies with increasing dose random or statistically significant and how large is the regression coefficient (= risk coefficient) in this case? These problems can be solved by sttistical tests. So-called distribution-free tests and tests which are not bound to the supposition of normal distribution are of particular interest, such as: - χ 2 -independence test (test in contingency tables); - Fisher-Yates-test; - trend test according to Cochran; - rank correlation test given by Spearman. These tests are explained in terms of selected epidemiologic data, e.g. of leukaemia clusters, of the cancer mortality of the Japanese A-bomb survivors especially in the low dose range as well as on the sample of the cancer mortality in the high background area in Yangjiang (China). (orig.) [de

Statistical Significance and Effect Size: Two Sides of a Coin.

Science.gov (United States)

Fan, Xitao

This paper suggests that statistical significance testing and effect size are two sides of the same coin; they complement each other, but do not substitute for one another. Good research practice requires that both should be taken into consideration to make sound quantitative decisions. A Monte Carlo simulation experiment was conducted, and a…

Publication of statistically significant research findings in prosthodontics & implant dentistry in the context of other dental specialties.

Science.gov (United States)

Papageorgiou, Spyridon N; Kloukos, Dimitrios; Petridis, Haralampos; Pandis, Nikolaos

2015-10-01

To assess the hypothesis that there is excessive reporting of statistically significant studies published in prosthodontic and implantology journals, which could indicate selective publication. The last 30 issues of 9 journals in prosthodontics and implant dentistry were hand-searched for articles with statistical analyses. The percentages of significant and non-significant results were tabulated by parameter of interest. Univariable/multivariable logistic regression analyses were applied to identify possible predictors of reporting statistically significance findings. The results of this study were compared with similar studies in dentistry with random-effects meta-analyses. From the 2323 included studies 71% of them reported statistically significant results, with the significant results ranging from 47% to 86%. Multivariable modeling identified that geographical area and involvement of statistician were predictors of statistically significant results. Compared to interventional studies, the odds that in vitro and observational studies would report statistically significant results was increased by 1.20 times (OR: 2.20, 95% CI: 1.66-2.92) and 0.35 times (OR: 1.35, 95% CI: 1.05-1.73), respectively. The probability of statistically significant results from randomized controlled trials was significantly lower compared to various study designs (difference: 30%, 95% CI: 11-49%). Likewise the probability of statistically significant results in prosthodontics and implant dentistry was lower compared to other dental specialties, but this result did not reach statistical significant (P>0.05). The majority of studies identified in the fields of prosthodontics and implant dentistry presented statistically significant results. The same trend existed in publications of other specialties in dentistry. Copyright © 2015 Elsevier Ltd. All rights reserved.

Significant Statistics: Viewed with a Contextual Lens

Science.gov (United States)

Tait-McCutcheon, Sandi

2010-01-01

This paper examines the pedagogical and organisational changes three lead teachers made to their statistics teaching and learning programs. The lead teachers posed the research question: What would the effect of contextually integrating statistical investigations and literacies into other curriculum areas be on student achievement? By finding the…

"What If" Analyses: Ways to Interpret Statistical Significance Test Results Using EXCEL or "R"

Science.gov (United States)

Ozturk, Elif

2012-01-01

The present paper aims to review two motivations to conduct "what if" analyses using Excel and "R" to understand the statistical significance tests through the sample size context. "What if" analyses can be used to teach students what statistical significance tests really do and in applied research either prospectively to estimate what sample size…

Statistical vs. Economic Significance in Economics and Econometrics: Further comments on McCloskey & Ziliak

DEFF Research Database (Denmark)

Engsted, Tom

I comment on the controversy between McCloskey & Ziliak and Hoover & Siegler on statistical versus economic significance, in the March 2008 issue of the Journal of Economic Methodology. I argue that while McCloskey & Ziliak are right in emphasizing 'real error', i.e. non-sampling error that cannot...... be eliminated through specification testing, they fail to acknowledge those areas in economics, e.g. rational expectations macroeconomics and asset pricing, where researchers clearly distinguish between statistical and economic significance and where statistical testing plays a relatively minor role in model...

Identification and Analysis of Significant Factors Influencing Visitor Satisfaction at Heritage Sites – The Case of Serbian Medieval Fortresses

Directory of Open Access Journals (Sweden)

Ivana Blešić

2013-01-01

Full Text Available With increased appreciation of general public, heritage sites gained more attention regarding contemporary tourism and management studies. Accordingly, the assessment of visitors’ satisfaction on these sites is important tool for both financial and organization management. The aim of this research is to identify the main (statistically significant factors that influence visitors’ satisfaction. Data was obtained by survey conducted during the visit of three medieval fortresses in Serbia, with aim to capture tourist’s expectations and perceptions on ten given attributes. The results of factor and descriptive statistical analysis indicate three factors: “regional settings”, “marketing”, “aesthetic appeal” significant for visitors’ satisfaction of the investigated heritage sites.

Influence of manufacturing parameters on the strength of PLA parts using Layered Manufacturing technique: A statistical approach

Science.gov (United States)

Jaya Christiyan, K. G.; Chandrasekhar, U.; Mathivanan, N. Rajesh; Venkateswarlu, K.

2018-02-01

A 3D printing was successfully used to fabricate samples of Polylactic Acid (PLA). Processing parameters such as Lay-up speed, Lay-up thickness, and printing nozzle were varied. All samples were tested for flexural strength using three point load test. A statistical mathematical model was developed to correlate the processing parameters with flexural strength. The result clearly demonstrated that the lay-up thickness and nozzle diameter influenced flexural strength significantly, whereas lay-up speed hardly influenced the flexural strength.

Distinguishing between statistical significance and practical/clinical meaningfulness using statistical inference.

Science.gov (United States)

Wilkinson, Michael

2014-03-01

Decisions about support for predictions of theories in light of data are made using statistical inference. The dominant approach in sport and exercise science is the Neyman-Pearson (N-P) significance-testing approach. When applied correctly it provides a reliable procedure for making dichotomous decisions for accepting or rejecting zero-effect null hypotheses with known and controlled long-run error rates. Type I and type II error rates must be specified in advance and the latter controlled by conducting an a priori sample size calculation. The N-P approach does not provide the probability of hypotheses or indicate the strength of support for hypotheses in light of data, yet many scientists believe it does. Outcomes of analyses allow conclusions only about the existence of non-zero effects, and provide no information about the likely size of true effects or their practical/clinical value. Bayesian inference can show how much support data provide for different hypotheses, and how personal convictions should be altered in light of data, but the approach is complicated by formulating probability distributions about prior subjective estimates of population effects. A pragmatic solution is magnitude-based inference, which allows scientists to estimate the true magnitude of population effects and how likely they are to exceed an effect magnitude of practical/clinical importance, thereby integrating elements of subjective Bayesian-style thinking. While this approach is gaining acceptance, progress might be hastened if scientists appreciate the shortcomings of traditional N-P null hypothesis significance testing.

Codon Deviation Coefficient: a novel measure for estimating codon usage bias and its statistical significance

Directory of Open Access Journals (Sweden)

Zhang Zhang

2012-03-01

Full Text Available Abstract Background Genetic mutation, selective pressure for translational efficiency and accuracy, level of gene expression, and protein function through natural selection are all believed to lead to codon usage bias (CUB. Therefore, informative measurement of CUB is of fundamental importance to making inferences regarding gene function and genome evolution. However, extant measures of CUB have not fully accounted for the quantitative effect of background nucleotide composition and have not statistically evaluated the significance of CUB in sequence analysis. Results Here we propose a novel measure--Codon Deviation Coefficient (CDC--that provides an informative measurement of CUB and its statistical significance without requiring any prior knowledge. Unlike previous measures, CDC estimates CUB by accounting for background nucleotide compositions tailored to codon positions and adopts the bootstrapping to assess the statistical significance of CUB for any given sequence. We evaluate CDC by examining its effectiveness on simulated sequences and empirical data and show that CDC outperforms extant measures by achieving a more informative estimation of CUB and its statistical significance. Conclusions As validated by both simulated and empirical data, CDC provides a highly informative quantification of CUB and its statistical significance, useful for determining comparative magnitudes and patterns of biased codon usage for genes or genomes with diverse sequence compositions.

Statistics Refresher for Molecular Imaging Technologists, Part 2: Accuracy of Interpretation, Significance, and Variance.

Science.gov (United States)

Farrell, Mary Beth

2018-06-01

This article is the second part of a continuing education series reviewing basic statistics that nuclear medicine and molecular imaging technologists should understand. In this article, the statistics for evaluating interpretation accuracy, significance, and variance are discussed. Throughout the article, actual statistics are pulled from the published literature. We begin by explaining 2 methods for quantifying interpretive accuracy: interreader and intrareader reliability. Agreement among readers can be expressed simply as a percentage. However, the Cohen κ-statistic is a more robust measure of agreement that accounts for chance. The higher the κ-statistic is, the higher is the agreement between readers. When 3 or more readers are being compared, the Fleiss κ-statistic is used. Significance testing determines whether the difference between 2 conditions or interventions is meaningful. Statistical significance is usually expressed using a number called a probability ( P ) value. Calculation of P value is beyond the scope of this review. However, knowing how to interpret P values is important for understanding the scientific literature. Generally, a P value of less than 0.05 is considered significant and indicates that the results of the experiment are due to more than just chance. Variance, standard deviation (SD), confidence interval, and standard error (SE) explain the dispersion of data around a mean of a sample drawn from a population. SD is commonly reported in the literature. A small SD indicates that there is not much variation in the sample data. Many biologic measurements fall into what is referred to as a normal distribution taking the shape of a bell curve. In a normal distribution, 68% of the data will fall within 1 SD, 95% will fall within 2 SDs, and 99.7% will fall within 3 SDs. Confidence interval defines the range of possible values within which the population parameter is likely to lie and gives an idea of the precision of the statistic being

Systematic reviews of anesthesiologic interventions reported as statistically significant

DEFF Research Database (Denmark)

Imberger, Georgina; Gluud, Christian; Boylan, John

2015-01-01

statistically significant meta-analyses of anesthesiologic interventions, we used TSA to estimate power and imprecision in the context of sparse data and repeated updates. METHODS: We conducted a search to identify all systematic reviews with meta-analyses that investigated an intervention that may......: From 11,870 titles, we found 682 systematic reviews that investigated anesthesiologic interventions. In the 50 sampled meta-analyses, the median number of trials included was 8 (interquartile range [IQR], 5-14), the median number of participants was 964 (IQR, 523-1736), and the median number...

Using the Bootstrap Method for a Statistical Significance Test of Differences between Summary Histograms

Science.gov (United States)

Xu, Kuan-Man

2006-01-01

A new method is proposed to compare statistical differences between summary histograms, which are the histograms summed over a large ensemble of individual histograms. It consists of choosing a distance statistic for measuring the difference between summary histograms and using a bootstrap procedure to calculate the statistical significance level. Bootstrapping is an approach to statistical inference that makes few assumptions about the underlying probability distribution that describes the data. Three distance statistics are compared in this study. They are the Euclidean distance, the Jeffries-Matusita distance and the Kuiper distance. The data used in testing the bootstrap method are satellite measurements of cloud systems called cloud objects. Each cloud object is defined as a contiguous region/patch composed of individual footprints or fields of view. A histogram of measured values over footprints is generated for each parameter of each cloud object and then summary histograms are accumulated over all individual histograms in a given cloud-object size category. The results of statistical hypothesis tests using all three distances as test statistics are generally similar, indicating the validity of the proposed method. The Euclidean distance is determined to be most suitable after comparing the statistical tests of several parameters with distinct probability distributions among three cloud-object size categories. Impacts on the statistical significance levels resulting from differences in the total lengths of satellite footprint data between two size categories are also discussed.

P-Value, a true test of statistical significance? a cautionary note ...

African Journals Online (AJOL)

While it's not the intention of the founders of significance testing and hypothesis testing to have the two ideas intertwined as if they are complementary, the inconvenient marriage of the two practices into one coherent, convenient, incontrovertible and misinterpreted practice has dotted our standard statistics textbooks and ...

The influence of narrative v. statistical information on perceiving vaccination risks.

Science.gov (United States)

Betsch, Cornelia; Ulshöfer, Corina; Renkewitz, Frank; Betsch, Tilmann

2011-01-01

Health-related information found on the Internet is increasing and impacts patient decision making, e.g. regarding vaccination decisions. In addition to statistical information (e.g. incidence rates of vaccine adverse events), narrative information is also widely available such as postings on online bulletin boards. Previous research has shown that narrative information can impact treatment decisions, even when statistical information is presented concurrently. As the determinants of this effect are largely unknown, we will vary features of the narratives to identify mechanisms through which narratives impact risk judgments. An online bulletin board setting provided participants with statistical information and authentic narratives about the occurrence and nonoccurrence of adverse events. Experiment 1 followed a single factorial design with 1, 2, or 4 narratives out of 10 reporting adverse events. Experiment 2 implemented a 2 (statistical risk 20% vs. 40%) × 2 (2/10 vs. 4/10 narratives reporting adverse events) × 2 (high vs. low richness) × 2 (high vs. low emotionality) between-subjects design. Dependent variables were perceived risk of side-effects and vaccination intentions. Experiment 1 shows an inverse relation between the number of narratives reporting adverse-events and vaccination intentions, which was mediated by the perceived risk of vaccinating. Experiment 2 showed a stronger influence of the number of narratives than of the statistical risk information. High (vs. low) emotional narratives had a greater impact on the perceived risk, while richness had no effect. The number of narratives influences risk judgments can potentially override statistical information about risk.

Codon Deviation Coefficient: A novel measure for estimating codon usage bias and its statistical significance

KAUST Repository

Zhang, Zhang

2012-03-22

Background: Genetic mutation, selective pressure for translational efficiency and accuracy, level of gene expression, and protein function through natural selection are all believed to lead to codon usage bias (CUB). Therefore, informative measurement of CUB is of fundamental importance to making inferences regarding gene function and genome evolution. However, extant measures of CUB have not fully accounted for the quantitative effect of background nucleotide composition and have not statistically evaluated the significance of CUB in sequence analysis.Results: Here we propose a novel measure--Codon Deviation Coefficient (CDC)--that provides an informative measurement of CUB and its statistical significance without requiring any prior knowledge. Unlike previous measures, CDC estimates CUB by accounting for background nucleotide compositions tailored to codon positions and adopts the bootstrapping to assess the statistical significance of CUB for any given sequence. We evaluate CDC by examining its effectiveness on simulated sequences and empirical data and show that CDC outperforms extant measures by achieving a more informative estimation of CUB and its statistical significance.Conclusions: As validated by both simulated and empirical data, CDC provides a highly informative quantification of CUB and its statistical significance, useful for determining comparative magnitudes and patterns of biased codon usage for genes or genomes with diverse sequence compositions. 2012 Zhang et al; licensee BioMed Central Ltd.

Interpreting Statistical Significance Test Results: A Proposed New "What If" Method.

Science.gov (United States)

Kieffer, Kevin M.; Thompson, Bruce

As the 1994 publication manual of the American Psychological Association emphasized, "p" values are affected by sample size. As a result, it can be helpful to interpret the results of statistical significant tests in a sample size context by conducting so-called "what if" analyses. However, these methods can be inaccurate…

Measuring individual significant change on the Beck Depression Inventory-II through IRT-based statistics.

NARCIS (Netherlands)

Brouwer, D.; Meijer, R.R.; Zevalkink, D.J.

2013-01-01

Several researchers have emphasized that item response theory (IRT)-based methods should be preferred over classical approaches in measuring change for individual patients. In the present study we discuss and evaluate the use of IRT-based statistics to measure statistical significant individual

Strategies for Testing Statistical and Practical Significance in Detecting DIF with Logistic Regression Models

Science.gov (United States)

Fidalgo, Angel M.; Alavi, Seyed Mohammad; Amirian, Seyed Mohammad Reza

2014-01-01

This study examines three controversial aspects in differential item functioning (DIF) detection by logistic regression (LR) models: first, the relative effectiveness of different analytical strategies for detecting DIF; second, the suitability of the Wald statistic for determining the statistical significance of the parameters of interest; and…

Statistical determination of significant curved I-girder bridge seismic response parameters

Science.gov (United States)

Seo, Junwon

2013-06-01

Curved steel bridges are commonly used at interchanges in transportation networks and more of these structures continue to be designed and built in the United States. Though the use of these bridges continues to increase in locations that experience high seismicity, the effects of curvature and other parameters on their seismic behaviors have been neglected in current risk assessment tools. These tools can evaluate the seismic vulnerability of a transportation network using fragility curves. One critical component of fragility curve development for curved steel bridges is the completion of sensitivity analyses that help identify influential parameters related to their seismic response. In this study, an accessible inventory of existing curved steel girder bridges located primarily in the Mid-Atlantic United States (MAUS) was used to establish statistical characteristics used as inputs for a seismic sensitivity study. Critical seismic response quantities were captured using 3D nonlinear finite element models. Influential parameters from these quantities were identified using statistical tools that incorporate experimental Plackett-Burman Design (PBD), which included Pareto optimal plots and prediction profiler techniques. The findings revealed that the potential variation in the influential parameters included number of spans, radius of curvature, maximum span length, girder spacing, and cross-frame spacing. These parameters showed varying levels of influence on the critical bridge response.

Thresholds for statistical and clinical significance in systematic reviews with meta-analytic methods

DEFF Research Database (Denmark)

Jakobsen, Janus Christian; Wetterslev, Jorn; Winkel, Per

2014-01-01

BACKGROUND: Thresholds for statistical significance when assessing meta-analysis results are being insufficiently demonstrated by traditional 95% confidence intervals and P-values. Assessment of intervention effects in systematic reviews with meta-analysis deserves greater rigour. METHODS......: Methodologies for assessing statistical and clinical significance of intervention effects in systematic reviews were considered. Balancing simplicity and comprehensiveness, an operational procedure was developed, based mainly on The Cochrane Collaboration methodology and the Grading of Recommendations...... Assessment, Development, and Evaluation (GRADE) guidelines. RESULTS: We propose an eight-step procedure for better validation of meta-analytic results in systematic reviews (1) Obtain the 95% confidence intervals and the P-values from both fixed-effect and random-effects meta-analyses and report the most...

Statistical estimate of factors influence on sorption of Mo(Ⅵ) ions by tin hydroxide in dynamic conditions

International Nuclear Information System (INIS)

Parshutkin, V.V.; Granovskiy, Yu.V.; Prozorovskaya, Z.N.

1986-01-01

Present work is devoted to statistical estimate of factors influence on sorption of Mo(Ⅵ) ions by tin hydroxide in dynamic conditions. The influence of different factors on the process of sorption of Co(Ⅵ) ions by cryo-granular tin hydroxide in dynamic conditions is studied and optimal conditions of their extraction from aqueous solutions are considered. It is defined that factors significant affect the sorption process in dynamic conditions are: concentration of Mo(Ⅵ) ions in solution; the mass of sorbent; the rate of transmission of solution through the layer of sorbent; concentration of SO 4 2- ions in solution.

Statistical Signs of Social Influence on Suicides

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Melo, Hygor Piaget M.; Moreira, André A.; Batista, Élcio; Makse, Hernán A.; Andrade, José S.

2014-09-01

By treating the suicide as a social fact, Durkheim envisaged that suicide rates should be determined by the connections between people and society. Under the same framework, he considered that crime is bound up with the fundamental conditions of all social life. The social effect on the occurrence of homicides has been previously substantiated, and confirmed here, in terms of a superlinear scaling relation: by doubling the population of a Brazilian city results in an average increment of 135% in the number of homicides, rather than the expected isometric increase of 100%, as found, for example, for the mortality due to car crashes. Here we present statistical signs of the social influence on the suicide occurrence in cities. Differently from homicides (superlinear) and fatal events in car crashes (isometric), we find sublinear scaling behavior between the number of suicides and city population, with allometric power-law exponents, β = 0.84 +/- 0.02 and 0.87 +/- 0.01, for all cities in Brazil and US counties, respectively. Also for suicides in US, but using the Metropolitan Statistical Areas (MSAs), we obtain β = 0.88 +/- 0.01.

Side effects of being blue: influence of sad mood on visual statistical learning.

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Julie Bertels

Full Text Available It is well established that mood influences many cognitive processes, such as learning and executive functions. Although statistical learning is assumed to be part of our daily life, as mood does, the influence of mood on statistical learning has never been investigated before. In the present study, a sad vs. neutral mood was induced to the participants through the listening of stories while they were exposed to a stream of visual shapes made up of the repeated presentation of four triplets, namely sequences of three shapes presented in a fixed order. Given that the inter-stimulus interval was held constant within and between triplets, the only cues available for triplet segmentation were the transitional probabilities between shapes. Direct and indirect measures of learning taken either immediately or 20 minutes after the exposure/mood induction phase revealed that participants learned the statistical regularities between shapes. Interestingly, although participants from the sad and neutral groups performed similarly in these tasks, subjective measures (confidence judgments taken after each trial revealed that participants who experienced the sad mood induction showed increased conscious access to their statistical knowledge. These effects were not modulated by the time delay between the exposure/mood induction and the test phases. These results are discussed within the scope of the robustness principle and the influence of negative affects on processing style.

Statistical ultrasonics: the influence of Robert F. Wagner

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Insana, Michael F.

2009-02-01

An important ongoing question for higher education is how to successfully mentor the next generation of scientists and engineers. It has been my privilege to have been mentored by one of the best, Dr Robert F. Wagner and his colleagues at the CDRH/FDA during the mid 1980s. Bob introduced many of us in medical ultrasonics to statistical imaging techniques. These ideas continue to broadly influence studies on adaptive aperture management (beamforming, speckle suppression, compounding), tissue characterization (texture features, Rayleigh/Rician statistics, scatterer size and number density estimators), and fundamental questions about how limitations of the human eye-brain system for extracting information from textured images can motivate image processing. He adapted the classical techniques of signal detection theory to coherent imaging systems that, for the first time in ultrasonics, related common engineering metrics for image quality to task-based clinical performance. This talk summarizes my wonderfully-exciting three years with Bob as I watched him explore topics in statistical image analysis that formed a rational basis for many of the signal processing techniques used in commercial systems today. It is a story of an exciting time in medical ultrasonics, and of how a sparkling personality guided and motivated the development of junior scientists who flocked around him in admiration and amazement.

Statistical analysis of the factors that influenced the mechanical properties improvement of cassava starch films

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Monteiro, Mayra; Oliveira, Victor; Santos, Francisco; Barros Neto, Eduardo; Silva, Karyn; Silva, Rayane; Henrique, João; Chibério, Abimaelle

2017-08-01

In order to obtain cassava starch films with improved mechanical properties in relation to the synthetic polymer in the packaging production, a complete factorial design 23 was carried out in order to investigate which factor significantly influences the tensile strength of the biofilm. The factors to be investigated were cassava starch, glycerol and modified clay contents. Modified bentonite clay was used as a filling material of the biofilm. Glycerol was the plasticizer used to thermoplastify cassava starch. The factorial analysis suggested a regression model capable of predicting the optimal mechanical property of the cassava starch film from the maximization of the tensile strength. The reliability of the regression model was tested by the correlation established with the experimental data through the following statistical analyse: Pareto graph. The modified clay was the factor of greater statistical significance on the observed response variable, being the factor that contributed most to the improvement of the mechanical property of the starch film. The factorial experiments showed that the interaction of glycerol with both modified clay and cassava starch was significant for the reduction of biofilm ductility. Modified clay and cassava starch contributed to the maximization of biofilm ductility, while glycerol contributed to the minimization.

Intensive inpatient treatment for bulimia nervosa: Statistical and clinical significance of symptom changes.

Science.gov (United States)

Diedrich, Alice; Schlegl, Sandra; Greetfeld, Martin; Fumi, Markus; Voderholzer, Ulrich

2018-03-01

This study examines the statistical and clinical significance of symptom changes during an intensive inpatient treatment program with a strong psychotherapeutic focus for individuals with severe bulimia nervosa. 295 consecutively admitted bulimic patients were administered the Structured Interview for Anorexic and Bulimic Syndromes-Self-Rating (SIAB-S), the Eating Disorder Inventory-2 (EDI-2), the Brief Symptom Inventory (BSI), and the Beck Depression Inventory-II (BDI-II) at treatment intake and discharge. Results indicated statistically significant symptom reductions with large effect sizes regarding severity of binge eating and compensatory behavior (SIAB-S), overall eating disorder symptom severity (EDI-2), overall psychopathology (BSI), and depressive symptom severity (BDI-II) even when controlling for antidepressant medication. The majority of patients showed either reliable (EDI-2: 33.7%, BSI: 34.8%, BDI-II: 18.1%) or even clinically significant symptom changes (EDI-2: 43.2%, BSI: 33.9%, BDI-II: 56.9%). Patients with clinically significant improvement were less distressed at intake and less likely to suffer from a comorbid borderline personality disorder when compared with those who did not improve to a clinically significant extent. Findings indicate that intensive psychotherapeutic inpatient treatment may be effective in about 75% of severely affected bulimic patients. For the remaining non-responding patients, inpatient treatment might be improved through an even stronger focus on the reduction of comorbid borderline personality traits.

Influence of the statistical distribution of bioassay measurement errors on the intake estimation

International Nuclear Information System (INIS)

Lee, T. Y; Kim, J. K

2006-01-01

The purpose of this study is to provide the guidance necessary for making a selection of error distributions by analyzing influence of statistical distribution for a type of bioassay measurement error on the intake estimation. For this purpose, intakes were estimated using maximum likelihood method for cases that error distributions are normal and lognormal, and comparisons between two distributions for the estimated intakes were made. According to the results of this study, in case that measurement results for lung retention are somewhat greater than the limit of detection it appeared that distribution types have negligible influence on the results. Whereas in case of measurement results for the daily excretion rate, the results obtained from assumption of a lognormal distribution were 10% higher than those obtained from assumption of a normal distribution. In view of these facts, in case where uncertainty component is governed by counting statistics it is considered that distribution type have no influence on intake estimation. Whereas in case where the others are predominant, it is concluded that it is clearly desirable to estimate the intake assuming a lognormal distribution

Cloud-based solution to identify statistically significant MS peaks differentiating sample categories.

Science.gov (United States)

Ji, Jun; Ling, Jeffrey; Jiang, Helen; Wen, Qiaojun; Whitin, John C; Tian, Lu; Cohen, Harvey J; Ling, Xuefeng B

2013-03-23

Mass spectrometry (MS) has evolved to become the primary high throughput tool for proteomics based biomarker discovery. Until now, multiple challenges in protein MS data analysis remain: large-scale and complex data set management; MS peak identification, indexing; and high dimensional peak differential analysis with the concurrent statistical tests based false discovery rate (FDR). "Turnkey" solutions are needed for biomarker investigations to rapidly process MS data sets to identify statistically significant peaks for subsequent validation. Here we present an efficient and effective solution, which provides experimental biologists easy access to "cloud" computing capabilities to analyze MS data. The web portal can be accessed at http://transmed.stanford.edu/ssa/. Presented web application supplies large scale MS data online uploading and analysis with a simple user interface. This bioinformatic tool will facilitate the discovery of the potential protein biomarkers using MS.

Power, effects, confidence, and significance: an investigation of statistical practices in nursing research.

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Gaskin, Cadeyrn J; Happell, Brenda

2014-05-01

improvement. Most importantly, researchers should abandon the misleading practice of interpreting the results from inferential tests based solely on whether they are statistically significant (or not) and, instead, focus on reporting and interpreting effect sizes, confidence intervals, and significance levels. Nursing researchers also need to conduct and report a priori power analyses, and to address the issue of Type I experiment-wise error inflation in their studies. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Estimation of glandular content rate and statistical analysis of the influence of age group and compressed breast thickness on the estimated value

International Nuclear Information System (INIS)

Ohmori, Naoki; Ashida, Kenji; Fujita, Osamu

2003-01-01

Because the glandular content rate is an important factor in evaluating breast cancer detection and average glandular dose, it is important in mammography research to estimate and analyze this rate. The purpose of this study was to obtain a formula for statistical estimation of the glandular content rate, to clarify statistically the influence of age group and compressed breast thickness (CBT) on estimating the glandular content rate, and to show statistically the general relation between glandular content rate and the factors of age and CBT. The subjects were 740 Japanese women aged 20-91 years (mean±SD: 48.3±12.8 years) who had undergone mammography. In our study, the glandular content rate was statistically estimated from age group, mAs-value, and CBT when subjects underwent mammography, from a phantom simulation, and from MR images of the breast. In addition, multivariate analysis was carried to examine statistically the influence of age group and CBT on glandular content rate. The mean glandular content rate as estimated by age group was as follows: 35.6% for those in their 20s, 33.4% in the 30s, 27.5% in the 40s, 23.8% in the 50s, and 21.8% in those 60 and over. The rate for the subjects as a whole was 27.1%. This study indicated that overestimation occurred if the estimated value of the glandular content rate was not corrected in the 3D-measurement by MRI. In addition, this study showed that the statistical influence on glandular content rate was significantly larger for CBT than age. (author)

Examining reproducibility in psychology : A hybrid method for combining a statistically significant original study and a replication

NARCIS (Netherlands)

Van Aert, R.C.M.; Van Assen, M.A.L.M.

2018-01-01

The unrealistically high rate of positive results within psychology has increased the attention to replication research. However, researchers who conduct a replication and want to statistically combine the results of their replication with a statistically significant original study encounter

A tutorial on hunting statistical significance by chasing N

Directory of Open Access Journals (Sweden)

Denes Szucs

2016-09-01

Full Text Available There is increasing concern about the replicability of studies in psychology and cognitive neuroscience. Hidden data dredging (also called p-hacking is a major contributor to this crisis because it substantially increases Type I error resulting in a much larger proportion of false positive findings than the usually expected 5%. In order to build better intuition to avoid, detect and criticise some typical problems, here I systematically illustrate the large impact of some easy to implement and so, perhaps frequent data dredging techniques on boosting false positive findings. I illustrate several forms of two special cases of data dredging. First, researchers may violate the data collection stopping rules of null hypothesis significance testing by repeatedly checking for statistical significance with various numbers of participants. Second, researchers may group participants post-hoc along potential but unplanned independent grouping variables. The first approach 'hacks' the number of participants in studies, the second approach ‘hacks’ the number of variables in the analysis. I demonstrate the high amount of false positive findings generated by these techniques with data from true null distributions. I also illustrate that it is extremely easy to introduce strong bias into data by very mild selection and re-testing. Similar, usually undocumented data dredging steps can easily lead to having 20-50%, or more false positives.

Statistical Analysis and Evaluation of the Depth of the Ruts on Lithuanian State Significance Roads

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Erinijus Getautis

2011-04-01

Full Text Available The aim of this work is to gather information about the national flexible pavement roads ruts depth, to determine its statistical dispersijon index and to determine their validity for needed requirements. Analysis of scientific works of ruts apearance in the asphalt and their influence for driving is presented in this work. Dynamical models of ruts in asphalt are presented in the work as well. Experimental outcome data of rut depth dispersijon in the national highway of Lithuania Vilnius – Kaunas is prepared. Conclusions are formulated and presented. Article in Lithuanian

Manipulation of Ovarian Function Significantly Influenced Sarcopenia in Postreproductive-Age Mice

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Rhett L. Peterson

2016-01-01

Full Text Available Previously, transplantation of ovaries from young cycling mice into old postreproductive-age mice increased life span. We anticipated that the same factors that increased life span could also influence health span. Female CBA/J mice received new (60 d ovaries at 12 and 17 months of age and were evaluated at 16 and 25 months of age, respectively. There were no significant differences in body weight among any age or treatment group. The percentage of fat mass was significantly increased at 13 and 16 months of age but was reduced by ovarian transplantation in 16-month-old mice. The percentages of lean body mass and total body water were significantly reduced in 13-month-old control mice but were restored in 16- and 25-month-old recipient mice by ovarian transplantation to the levels found in six-month-old control mice. In summary, we have shown that skeletal muscle mass, which is negatively influenced by aging, can be positively influenced or restored by reestablishment of active ovarian function in aged female mice. These findings provide strong incentive for further investigation of the positive influence of young ovaries on restoration of health in postreproductive females.

A critical discussion of null hypothesis significance testing and statistical power analysis within psychological research

DEFF Research Database (Denmark)

Jones, Allan; Sommerlund, Bo

2007-01-01

The uses of null hypothesis significance testing (NHST) and statistical power analysis within psychological research are critically discussed. The article looks at the problems of relying solely on NHST when dealing with small and large sample sizes. The use of power-analysis in estimating...... the potential error introduced by small and large samples is advocated. Power analysis is not recommended as a replacement to NHST but as an additional source of information about the phenomena under investigation. Moreover, the importance of conceptual analysis in relation to statistical analysis of hypothesis...

Statistical significance estimation of a signal within the GooFit framework on GPUs

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Cristella Leonardo

2017-01-01

Full Text Available In order to test the computing capabilities of GPUs with respect to traditional CPU cores a high-statistics toy Monte Carlo technique has been implemented both in ROOT/RooFit and GooFit frameworks with the purpose to estimate the statistical significance of the structure observed by CMS close to the kinematical boundary of the J/ψϕ invariant mass in the three-body decay B+ → J/ψϕK+. GooFit is a data analysis open tool under development that interfaces ROOT/RooFit to CUDA platform on nVidia GPU. The optimized GooFit application running on GPUs hosted by servers in the Bari Tier2 provides striking speed-up performances with respect to the RooFit application parallelised on multiple CPUs by means of PROOF-Lite tool. The considerable resulting speed-up, evident when comparing concurrent GooFit processes allowed by CUDA Multi Process Service and a RooFit/PROOF-Lite process with multiple CPU workers, is presented and discussed in detail. By means of GooFit it has also been possible to explore the behaviour of a likelihood ratio test statistic in different situations in which the Wilks Theorem may or may not apply because its regularity conditions are not satisfied.

Measuring the moderating influence of gender on the acceptance of e-book amongst mathematics and statistics students at universities in Libya

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Asma Mohmead Smeda

2017-06-01

Full Text Available The success of using any types of technology in education depends on a large extent of the acceptance of information technology (IT by students. Therefore, understanding the factors influencing the acceptance of electronic book (e-book is essential for decision-makers and those interested in the e-book industry. Based on an extended technology acceptance model (TAM, this paper examines the impact of some factors on the students’ behavioural intention (BI toward adoption of the e-book in mathematics and statistics. This paper also investigates the effect of gender differences on the relationship between the factors affecting the acceptance of e-book. A self-administered survey was used to collect data from 392 mathematics and statistics undergraduate students. The research model has shown that the factors related to the social factor and users’ characteristics are the critical factors that affect the acceptance of the e-book. The results also indicated that perceived usefulness (PU, perceived ease of use (PEOU and students’ attitude (AU have strongly affected students’ BI. Self-efficacy (SE has a significant impact on PEOU while social influence (SI has a significant influence on students’ AU. Moreover, the results confirmed that most of the TAM constructs were significant in both models (males and females, where there are no differences between males and females; however, only PEOU has been affected by the gender moderator. The results showed that the impact of the factor of SI on females was more than males. On the other hand, female students were more confident in the use of the e-book than males. In general, the female students’ model was more powerful in explaining the variance than males’ model.

Statistical significance of theoretical predictions: A new dimension in nuclear structure theories (I)

International Nuclear Information System (INIS)

DUDEK, J; SZPAK, B; FORNAL, B; PORQUET, M-G

2011-01-01

In this and the follow-up article we briefly discuss what we believe represents one of the most serious problems in contemporary nuclear structure: the question of statistical significance of parametrizations of nuclear microscopic Hamiltonians and the implied predictive power of the underlying theories. In the present Part I, we introduce the main lines of reasoning of the so-called Inverse Problem Theory, an important sub-field in the contemporary Applied Mathematics, here illustrated on the example of the Nuclear Mean-Field Approach.

Significance of upper airway influence among patients of vocal cord dysfunction for its diagnosis: Role of impulse oscillometry

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Hira H

2009-01-01

Full Text Available Background: To identify the patients of bronchial asthma (suspected or proven, not responding to optimal therapy, for the presence of vocal cord dysfunction (VCD and to compare the diagnostic ability of flow volume (FV loop and impulse oscillometry (IOS. Materials and Methods: Fifty one patients of suspected/proven bronchial asthma not responding to optimal therapy were included for the study. Each patient was subjected to both FV loop and IOS studies. Direct visualization of the vocal cords with flexible fiberoptic bronchoscope for the presence of inspiratory vocal cord adduction during quiet respiration, with speech, and while performing provocative maneuvers was carried out. All patients were subjected to simple pulmonary function tests and recording of FV loop. IOS was performed on each patient to look for the site of obstruction and upper airway influence. The observations of both FV loop and IO studies were compared. Results: Among 51 patients participated, 12 (23.53% had bronchoscopical evidence of VCD and were labeled as VCD-positive group and rest 39 were designated VCD negative. No statistically significant difference in pulmonary function test (prereversibility results between the VCD-positive and VCD-negative patients was found. Reversible airway obstruction was observed in 75% of the patients of VCD-positive group and 67.65% of the patients in the VCD-negative group. Only one patient in the VCD-positive and none in VCD-negative group had inspiratory limb flattening of FV loop. Upper airway influence was evident by IOS in 58.3% of patients in the VCD-positive group and in 15.4% of patients in the VCD-negative group. This difference was statistically significant (P < 0.005. Conclusion: VCD was a common finding in patients with symptoms suggestive of asthma and frequently coexists with asthma. IOS was found to be a useful screening test for VCD and was more sensitive than FV loop.

Statistical Significance of the Contribution of Variables to the PCA Solution: An Alternative Permutation Strategy

Science.gov (United States)

Linting, Marielle; van Os, Bart Jan; Meulman, Jacqueline J.

2011-01-01

In this paper, the statistical significance of the contribution of variables to the principal components in principal components analysis (PCA) is assessed nonparametrically by the use of permutation tests. We compare a new strategy to a strategy used in previous research consisting of permuting the columns (variables) of a data matrix…

A Note on Comparing the Power of Test Statistics at Low Significance Levels.

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Morris, Nathan; Elston, Robert

2011-01-01

It is an obvious fact that the power of a test statistic is dependent upon the significance (alpha) level at which the test is performed. It is perhaps a less obvious fact that the relative performance of two statistics in terms of power is also a function of the alpha level. Through numerous personal discussions, we have noted that even some competent statisticians have the mistaken intuition that relative power comparisons at traditional levels such as α = 0.05 will be roughly similar to relative power comparisons at very low levels, such as the level α = 5 × 10 -8 , which is commonly used in genome-wide association studies. In this brief note, we demonstrate that this notion is in fact quite wrong, especially with respect to comparing tests with differing degrees of freedom. In fact, at very low alpha levels the cost of additional degrees of freedom is often comparatively low. Thus we recommend that statisticians exercise caution when interpreting the results of power comparison studies which use alpha levels that will not be used in practice.

ClusterSignificance: A bioconductor package facilitating statistical analysis of class cluster separations in dimensionality reduced data

DEFF Research Database (Denmark)

Serviss, Jason T.; Gådin, Jesper R.; Eriksson, Per

2017-01-01

, e.g. genes in a specific pathway, alone can separate samples into these established classes. Despite this, the evaluation of class separations is often subjective and performed via visualization. Here we present the ClusterSignificance package; a set of tools designed to assess the statistical...... significance of class separations downstream of dimensionality reduction algorithms. In addition, we demonstrate the design and utility of the ClusterSignificance package and utilize it to determine the importance of long non-coding RNA expression in the identity of multiple hematological malignancies....

What influences the choice of assessment methods in health technology assessments? Statistical analysis of international health technology assessments from 1989 to 2002.

Science.gov (United States)

Draborg, Eva; Andersen, Christian Kronborg

2006-01-01

Health technology assessment (HTA) has been used as input in decision making worldwide for more than 25 years. However, no uniform definition of HTA or agreement on assessment methods exists, leaving open the question of what influences the choice of assessment methods in HTAs. The objective of this study is to analyze statistically a possible relationship between methods of assessment used in practical HTAs, type of assessed technology, type of assessors, and year of publication. A sample of 433 HTAs published by eleven leading institutions or agencies in nine countries was reviewed and analyzed by multiple logistic regression. The study shows that outsourcing of HTA reports to external partners is associated with a higher likelihood of using assessment methods, such as meta-analysis, surveys, economic evaluations, and randomized controlled trials; and with a lower likelihood of using assessment methods, such as literature reviews and "other methods". The year of publication was statistically related to the inclusion of economic evaluations and shows a decreasing likelihood during the year span. The type of assessed technology was related to economic evaluations with a decreasing likelihood, to surveys, and to "other methods" with a decreasing likelihood when pharmaceuticals were the assessed type of technology. During the period from 1989 to 2002, no major developments in assessment methods used in practical HTAs were shown statistically in a sample of 433 HTAs worldwide. Outsourcing to external assessors has a statistically significant influence on choice of assessment methods.

Second Language Experience Facilitates Statistical Learning of Novel Linguistic Materials.

Science.gov (United States)

Potter, Christine E; Wang, Tianlin; Saffran, Jenny R

2017-04-01

Recent research has begun to explore individual differences in statistical learning, and how those differences may be related to other cognitive abilities, particularly their effects on language learning. In this research, we explored a different type of relationship between language learning and statistical learning: the possibility that learning a new language may also influence statistical learning by changing the regularities to which learners are sensitive. We tested two groups of participants, Mandarin Learners and Naïve Controls, at two time points, 6 months apart. At each time point, participants performed two different statistical learning tasks: an artificial tonal language statistical learning task and a visual statistical learning task. Only the Mandarin-learning group showed significant improvement on the linguistic task, whereas both groups improved equally on the visual task. These results support the view that there are multiple influences on statistical learning. Domain-relevant experiences may affect the regularities that learners can discover when presented with novel stimuli. Copyright © 2016 Cognitive Science Society, Inc.

Statistical significance versus clinical importance: trials on exercise therapy for chronic low back pain as example.

NARCIS (Netherlands)

van Tulder, M.W.; Malmivaara, A.; Hayden, J.; Koes, B.

2007-01-01

STUDY DESIGN. Critical appraisal of the literature. OBJECIVES. The objective of this study was to assess if results of back pain trials are statistically significant and clinically important. SUMMARY OF BACKGROUND DATA. There seems to be a discrepancy between conclusions reported by authors and

Attitudes toward statistics in medical postgraduates: measuring, evaluating and monitoring.

Science.gov (United States)

Zhang, Yuhai; Shang, Lei; Wang, Rui; Zhao, Qinbo; Li, Chanjuan; Xu, Yongyong; Su, Haixia

2012-11-23

In medical training, statistics is considered a very difficult course to learn and teach. Current studies have found that students' attitudes toward statistics can influence their learning process. Measuring, evaluating and monitoring the changes of students' attitudes toward statistics are important. Few studies have focused on the attitudes of postgraduates, especially medical postgraduates. Our purpose was to understand current attitudes regarding statistics held by medical postgraduates and explore their effects on students' achievement. We also wanted to explore the influencing factors and the sources of these attitudes and monitor their changes after a systematic statistics course. A total of 539 medical postgraduates enrolled in a systematic statistics course completed the pre-form of the Survey of Attitudes Toward Statistics -28 scale, and 83 postgraduates were selected randomly from among them to complete the post-form scale after the course. Most medical postgraduates held positive attitudes toward statistics, but they thought statistics was a very difficult subject. The attitudes mainly came from experiences in a former statistical or mathematical class. Age, level of statistical education, research experience, specialty and mathematics basis may influence postgraduate attitudes toward statistics. There were significant positive correlations between course achievement and attitudes toward statistics. In general, student attitudes showed negative changes after completing a statistics course. The importance of student attitudes toward statistics must be recognized in medical postgraduate training. To make sure all students have a positive learning environment, statistics teachers should measure their students' attitudes and monitor their change of status during a course. Some necessary assistance should be offered for those students who develop negative attitudes.

Factors influencing medical informatics examination grade--can biorhythm, astrological sign, seasonal aspect, or bad statistics predict outcome?

Science.gov (United States)

Petrovecki, Mladen; Rahelić, Dario; Bilić-Zulle, Lidija; Jelec, Vjekoslav

2003-02-01

To investigate whether and to what extent various parameters, such as individual characteristics, computer habits, situational factors, and pseudoscientific variables, influence Medical Informatics examination grade, and how inadequate statistical analysis can lead to wrong conclusions. The study included a total of 382 second-year undergraduate students at the Rijeka University School of Medicine in the period from 1996/97 to 2000/01 academic year. After passing the Medical Informatics exam, students filled out an anonymous questionnaire about their attitude toward learning medical informatics. They were asked to grade the course organization and curriculum content, and provide their date of birth; sex; study year; high school grades; Medical Informatics examination grade, type, and term; and describe their computer habits. From these data, we determined their zodiac signs and biorhythm. Data were compared by the use of t-test, one-way ANOVA with Tukey's honest significance difference test, and randomized complete block design ANOVA. Out of 21 variables analyzed, only 10 correlated with the average grade. Students taking Medical Informatics examination in the 1998/99 academic year earned lower average grade than any other generation. Significantly higher Medical Informatics exam grade was earned by students who finished a grammar high school; owned and regularly used a computer, Internet, and e-mail (pzodiac sign, zodiac sign quality, or biorhythm cycles, except when intentionally inadequate statistics was used for data analysis. Medical Informatics examination grades correlated with general learning capacity and computer habits of students, but showed no relation to other investigated parameters, such as examination term or pseudoscientific parameters. Inadequate statistical analysis can always confirm false conclusions.

Breakthroughs in statistics

CERN Document Server

Johnson, Norman

This is author-approved bcc: This is the third volume of a collection of seminal papers in the statistical sciences written during the past 110 years. These papers have each had an outstanding influence on the development of statistical theory and practice over the last century. Each paper is preceded by an introduction written by an authority in the field providing background information and assessing its influence. Volume III concerntrates on articles from the 1980's while including some earlier articles not included in Volume I and II. Samuel Kotz is Professor of Statistics in the College of Business and Management at the University of Maryland. Norman L. Johnson is Professor Emeritus of Statistics at the University of North Carolina. Also available: Breakthroughs in Statistics Volume I: Foundations and Basic Theory Samuel Kotz and Norman L. Johnson, Editors 1993. 631 pp. Softcover. ISBN 0-387-94037-5 Breakthroughs in Statistics Volume II: Methodology and Distribution Samuel Kotz and Norman L. Johnson, Edi...

A laboratory evaluation of the influence of weighing gauges performance on extreme events statistics

Science.gov (United States)

Colli, Matteo; Lanza, Luca

2014-05-01

The effects of inaccurate ground based rainfall measurements on the information derived from rain records is yet not much documented in the literature. La Barbera et al. (2002) investigated the propagation of the systematic mechanic errors of tipping bucket type rain gauges (TBR) into the most common statistics of rainfall extremes, e.g. in the assessment of the return period T (or the related non-exceedance probability) of short-duration/high intensity events. Colli et al. (2012) and Lanza et al. (2012) extended the analysis to a 22-years long precipitation data set obtained from a virtual weighing type gauge (WG). The artificial WG time series was obtained basing on real precipitation data measured at the meteo-station of the University of Genova and modelling the weighing gauge output as a linear dynamic system. This approximation was previously validated with dedicated laboratory experiments and is based on the evidence that the accuracy of WG measurements under real world/time varying rainfall conditions is mainly affected by the dynamic response of the gauge (as revealed during the last WMO Field Intercomparison of Rainfall Intensity Gauges). The investigation is now completed by analyzing actual measurements performed by two common weighing gauges, the OTT Pluvio2 load-cell gauge and the GEONOR T-200 vibrating-wire gauge, since both these instruments demonstrated very good performance under previous constant flow rate calibration efforts. A laboratory dynamic rainfall generation system has been arranged and validated in order to simulate a number of precipitation events with variable reference intensities. Such artificial events were generated basing on real world rainfall intensity (RI) records obtained from the meteo-station of the University of Genova so that the statistical structure of the time series is preserved. The influence of the WG RI measurements accuracy on the associated extreme events statistics is analyzed by comparing the original intensity

Attitudes toward statistics in medical postgraduates: measuring, evaluating and monitoring

Science.gov (United States)

2012-01-01

Background In medical training, statistics is considered a very difficult course to learn and teach. Current studies have found that students’ attitudes toward statistics can influence their learning process. Measuring, evaluating and monitoring the changes of students’ attitudes toward statistics are important. Few studies have focused on the attitudes of postgraduates, especially medical postgraduates. Our purpose was to understand current attitudes regarding statistics held by medical postgraduates and explore their effects on students’ achievement. We also wanted to explore the influencing factors and the sources of these attitudes and monitor their changes after a systematic statistics course. Methods A total of 539 medical postgraduates enrolled in a systematic statistics course completed the pre-form of the Survey of Attitudes Toward Statistics −28 scale, and 83 postgraduates were selected randomly from among them to complete the post-form scale after the course. Results Most medical postgraduates held positive attitudes toward statistics, but they thought statistics was a very difficult subject. The attitudes mainly came from experiences in a former statistical or mathematical class. Age, level of statistical education, research experience, specialty and mathematics basis may influence postgraduate attitudes toward statistics. There were significant positive correlations between course achievement and attitudes toward statistics. In general, student attitudes showed negative changes after completing a statistics course. Conclusions The importance of student attitudes toward statistics must be recognized in medical postgraduate training. To make sure all students have a positive learning environment, statistics teachers should measure their students’ attitudes and monitor their change of status during a course. Some necessary assistance should be offered for those students who develop negative attitudes. PMID:23173770

Indirectional statistics and the significance of an asymmetry discovered by Birch

International Nuclear Information System (INIS)

Kendall, D.G.; Young, G.A.

1984-01-01

Birch (1982, Nature, 298, 451) reported an apparent 'statistical asymmetry of the Universe'. The authors here develop 'indirectional analysis' as a technique for investigating statistical effects of this kind and conclude that the reported effect (whatever may be its origin) is strongly supported by the observations. The estimated pole of the asymmetry is at RA 13h 30m, Dec. -37deg. The angular error in its estimation is unlikely to exceed 20-30deg. (author)

Testing statistical self-similarity in the topology of river networks

Science.gov (United States)

Troutman, Brent M.; Mantilla, Ricardo; Gupta, Vijay K.

2010-01-01

Recent work has demonstrated that the topological properties of real river networks deviate significantly from predictions of Shreve's random model. At the same time the property of mean self-similarity postulated by Tokunaga's model is well supported by data. Recently, a new class of network model called random self-similar networks (RSN) that combines self-similarity and randomness has been introduced to replicate important topological features observed in real river networks. We investigate if the hypothesis of statistical self-similarity in the RSN model is supported by data on a set of 30 basins located across the continental United States that encompass a wide range of hydroclimatic variability. We demonstrate that the generators of the RSN model obey a geometric distribution, and self-similarity holds in a statistical sense in 26 of these 30 basins. The parameters describing the distribution of interior and exterior generators are tested to be statistically different and the difference is shown to produce the well-known Hack's law. The inter-basin variability of RSN parameters is found to be statistically significant. We also test generator dependence on two climatic indices, mean annual precipitation and radiative index of dryness. Some indication of climatic influence on the generators is detected, but this influence is not statistically significant with the sample size available. Finally, two key applications of the RSN model to hydrology and geomorphology are briefly discussed.

[Big data in official statistics].

Science.gov (United States)

Zwick, Markus

2015-08-01

The concept of "big data" stands to change the face of official statistics over the coming years, having an impact on almost all aspects of data production. The tasks of future statisticians will not necessarily be to produce new data, but rather to identify and make use of existing data to adequately describe social and economic phenomena. Until big data can be used correctly in official statistics, a lot of questions need to be answered and problems solved: the quality of data, data protection, privacy, and the sustainable availability are some of the more pressing issues to be addressed. The essential skills of official statisticians will undoubtedly change, and this implies a number of challenges to be faced by statistical education systems, in universities, and inside the statistical offices. The national statistical offices of the European Union have concluded a concrete strategy for exploring the possibilities of big data for official statistics, by means of the Big Data Roadmap and Action Plan 1.0. This is an important first step and will have a significant influence on implementing the concept of big data inside the statistical offices of Germany.

Evaluation of significantly modified water bodies in Vojvodina by using multivariate statistical techniques

Directory of Open Access Journals (Sweden)

Vujović Svetlana R.

2013-01-01

Full Text Available This paper illustrates the utility of multivariate statistical techniques for analysis and interpretation of water quality data sets and identification of pollution sources/factors with a view to get better information about the water quality and design of monitoring network for effective management of water resources. Multivariate statistical techniques, such as factor analysis (FA/principal component analysis (PCA and cluster analysis (CA, were applied for the evaluation of variations and for the interpretation of a water quality data set of the natural water bodies obtained during 2010 year of monitoring of 13 parameters at 33 different sites. FA/PCA attempts to explain the correlations between the observations in terms of the underlying factors, which are not directly observable. Factor analysis is applied to physico-chemical parameters of natural water bodies with the aim classification and data summation as well as segmentation of heterogeneous data sets into smaller homogeneous subsets. Factor loadings were categorized as strong and moderate corresponding to the absolute loading values of >0.75, 0.75-0.50, respectively. Four principal factors were obtained with Eigenvalues >1 summing more than 78 % of the total variance in the water data sets, which is adequate to give good prior information regarding data structure. Each factor that is significantly related to specific variables represents a different dimension of water quality. The first factor F1 accounting for 28 % of the total variance and represents the hydrochemical dimension of water quality. The second factor F2 accounting for 18% of the total variance and may be taken factor of water eutrophication. The third factor F3 accounting 17 % of the total variance and represents the influence of point sources of pollution on water quality. The fourth factor F4 accounting 13 % of the total variance and may be taken as an ecological dimension of water quality. Cluster analysis (CA is an

Rapid Classification and Identification of Multiple Microorganisms with Accurate Statistical Significance via High-Resolution Tandem Mass Spectrometry.

Science.gov (United States)

Alves, Gelio; Wang, Guanghui; Ogurtsov, Aleksey Y; Drake, Steven K; Gucek, Marjan; Sacks, David B; Yu, Yi-Kuo

2018-06-05

Rapid and accurate identification and classification of microorganisms is of paramount importance to public health and safety. With the advance of mass spectrometry (MS) technology, the speed of identification can be greatly improved. However, the increasing number of microbes sequenced is complicating correct microbial identification even in a simple sample due to the large number of candidates present. To properly untwine candidate microbes in samples containing one or more microbes, one needs to go beyond apparent morphology or simple "fingerprinting"; to correctly prioritize the candidate microbes, one needs to have accurate statistical significance in microbial identification. We meet these challenges by using peptide-centric representations of microbes to better separate them and by augmenting our earlier analysis method that yields accurate statistical significance. Here, we present an updated analysis workflow that uses tandem MS (MS/MS) spectra for microbial identification or classification. We have demonstrated, using 226 MS/MS publicly available data files (each containing from 2500 to nearly 100,000 MS/MS spectra) and 4000 additional MS/MS data files, that the updated workflow can correctly identify multiple microbes at the genus and often the species level for samples containing more than one microbe. We have also shown that the proposed workflow computes accurate statistical significances, i.e., E values for identified peptides and unified E values for identified microbes. Our updated analysis workflow MiCId, a freely available software for Microorganism Classification and Identification, is available for download at https://www.ncbi.nlm.nih.gov/CBBresearch/Yu/downloads.html . Graphical Abstract ᅟ.

Methods of statistical calculation of fast reactor core with account of influence of fuel assembly form change in process of campaign and other factors

International Nuclear Information System (INIS)

Sorokin, G.A.; Zhukov, A.V.; Bogoslovskaya, G.P.; Sorokin, A.P.

2000-01-01

The method of calculation of a temperature field in fast reactor core using criterion equal thermo-technical reliability of subassemblies in various zones throttling taking into account change thermohydraulic characteristics of subassemblies during campaign under influence change form of core, redistribution heat generation, casual any deviation of various parameters is stated. The distribution of the statistical characteristics of a temperature field in subassemblies is calculated on subchannel method with account of an interchannel exchange and feature of influence of deformation on a temperature field in subassemblies using Monte-Carlo method. The results of the calculations show that deformation can have significant influence on a temperature mode of core. It is necessary to make thermohydraulic analysis of core during campaign at a stage of preliminary study of the projects fast reactors. (author)

Assessing Statistically Significant Heavy-Metal Concentrations in Abandoned Mine Areas via Hot Spot Analysis of Portable XRF Data.

Science.gov (United States)

Kim, Sung-Min; Choi, Yosoon

2017-06-18

To develop appropriate measures to prevent soil contamination in abandoned mining areas, an understanding of the spatial variation of the potentially toxic trace elements (PTEs) in the soil is necessary. For the purpose of effective soil sampling, this study uses hot spot analysis, which calculates a z -score based on the Getis-Ord Gi* statistic to identify a statistically significant hot spot sample. To constitute a statistically significant hot spot, a feature with a high value should also be surrounded by other features with high values. Using relatively cost- and time-effective portable X-ray fluorescence (PXRF) analysis, sufficient input data are acquired from the Busan abandoned mine and used for hot spot analysis. To calibrate the PXRF data, which have a relatively low accuracy, the PXRF analysis data are transformed using the inductively coupled plasma atomic emission spectrometry (ICP-AES) data. The transformed PXRF data of the Busan abandoned mine are classified into four groups according to their normalized content and z -scores: high content with a high z -score (HH), high content with a low z -score (HL), low content with a high z -score (LH), and low content with a low z -score (LL). The HL and LH cases may be due to measurement errors. Additional or complementary surveys are required for the areas surrounding these suspect samples or for significant hot spot areas. The soil sampling is conducted according to a four-phase procedure in which the hot spot analysis and proposed group classification method are employed to support the development of a sampling plan for the following phase. Overall, 30, 50, 80, and 100 samples are investigated and analyzed in phases 1-4, respectively. The method implemented in this case study may be utilized in the field for the assessment of statistically significant soil contamination and the identification of areas for which an additional survey is required.

Assessing Statistically Significant Heavy-Metal Concentrations in Abandoned Mine Areas via Hot Spot Analysis of Portable XRF Data

Directory of Open Access Journals (Sweden)

Sung-Min Kim

2017-06-01

Full Text Available To develop appropriate measures to prevent soil contamination in abandoned mining areas, an understanding of the spatial variation of the potentially toxic trace elements (PTEs in the soil is necessary. For the purpose of effective soil sampling, this study uses hot spot analysis, which calculates a z-score based on the Getis-Ord Gi* statistic to identify a statistically significant hot spot sample. To constitute a statistically significant hot spot, a feature with a high value should also be surrounded by other features with high values. Using relatively cost- and time-effective portable X-ray fluorescence (PXRF analysis, sufficient input data are acquired from the Busan abandoned mine and used for hot spot analysis. To calibrate the PXRF data, which have a relatively low accuracy, the PXRF analysis data are transformed using the inductively coupled plasma atomic emission spectrometry (ICP-AES data. The transformed PXRF data of the Busan abandoned mine are classified into four groups according to their normalized content and z-scores: high content with a high z-score (HH, high content with a low z-score (HL, low content with a high z-score (LH, and low content with a low z-score (LL. The HL and LH cases may be due to measurement errors. Additional or complementary surveys are required for the areas surrounding these suspect samples or for significant hot spot areas. The soil sampling is conducted according to a four-phase procedure in which the hot spot analysis and proposed group classification method are employed to support the development of a sampling plan for the following phase. Overall, 30, 50, 80, and 100 samples are investigated and analyzed in phases 1–4, respectively. The method implemented in this case study may be utilized in the field for the assessment of statistically significant soil contamination and the identification of areas for which an additional survey is required.

INFLUENCE OF STOCHASTIC NOISE STATISTICS ON KALMAN FILTER PERFORMANCE BASED ON VIDEO TARGET TRACKING

Institute of Scientific and Technical Information of China (English)

Chen Ken; Napolitano; Zhang Yun; Li Dong

2010-01-01

The system stochastic noises involved in Kalman filtering are preconditioned on being ideally white and Gaussian distributed. In this research,efforts are exerted on exploring the influence of the noise statistics on Kalman filtering from the perspective of video target tracking quality. The correlation of tracking precision to both the process and measurement noise covariance is investigated; the signal-to-noise power density ratio is defined; the contribution of predicted states and measured outputs to Kalman filter behavior is discussed; the tracking precision relative sensitivity is derived and applied in this study case. The findings are expected to pave the way for future study on how the actual noise statistics deviating from the assumed ones impacts on the Kalman filter optimality and degradation in the application of video tracking.

Statistical analysis of the influence of wheat black point kernels on selected indicators of wheat flour quality

Directory of Open Access Journals (Sweden)

Petrov Verica D.

2011-01-01

Full Text Available The influence of wheat black point kernels on selected indicators of wheat flour quality - farinograph and extensograph indicators, amylolytic activity, wet gluten and flour ash content, were examined in this study. The examinations were conducted on samples of wheat harvested in the years 2007 and 2008 from the area of Central Banat in four treatments-control (without black point flour and with 2, 4 and 10% of black point flour which was added as a replacement for a part of the control sample. Statistically significant differences between treatments were observed on the dough stability, falling number and extensibility. The samples with 10% of black point flour had the lowest dough stability and the highest amylolytic activity and extensibility. There was a trend of the increasing 15 min drop and water absorption with the increased share of black point flour. Extensograph area, resistance and ratio resistance to extensibility decreased with the addition of black point flour, but not properly. Mahalanobis distance indicates that the addition of 10% black point flour had the greatest influence on the observed quality indicators, thus proving that black point contributes to the technological quality of wheat, i.e .flour.

Assessment of the factors with significant influence on safety culture

International Nuclear Information System (INIS)

Farcasiu, M.; Nitoi, M.

2013-01-01

In this paper, a qualitative and a quantitative evaluation of the factors with significant impact on safety culture were performed. These techniques were established and applied in accordance with IAEA standards. In order to show the applicability and opportunity of the methodology a specific case study was prepared: safety culture evaluation for INR Pitesti. The qualitative evaluation was performed using specific developed questionnaires. Through analysis of the completed questionnaires was established the development stage of safety culture at INR. The quantitative evaluation was performed using a guide to rate the influence factors. For each factor was identified the influence (negative or positive) and ranking score was estimated using scoring criteria. The results have emphasized safety culture stages. The paper demonstrates the fact that using both quantitative and qualitative assessment techniques, a practical value of the safety culture concept is given. (authors)

Statistically significant faunal differences among Middle Ordovician age, Chickamauga Group bryozoan bioherms, central Alabama

Energy Technology Data Exchange (ETDEWEB)

Crow, C.J.

1985-01-01

Middle Ordovician age Chickamauga Group carbonates crop out along the Birmingham and Murphrees Valley anticlines in central Alabama. The macrofossil contents on exposed surfaces of seven bioherms have been counted to determine their various paleontologic characteristics. Twelve groups of organisms are present in these bioherms. Dominant organisms include bryozoans, algae, brachiopods, sponges, pelmatozoans, stromatoporoids and corals. Minor accessory fauna include predators, scavengers and grazers such as gastropods, ostracods, trilobites, cephalopods and pelecypods. Vertical and horizontal niche zonation has been detected for some of the bioherm dwelling fauna. No one bioherm of those studied exhibits all 12 groups of organisms; rather, individual bioherms display various subsets of the total diversity. Statistical treatment (G-test) of the diversity data indicates a lack of statistical homogeneity of the bioherms, both within and between localities. Between-locality population heterogeneity can be ascribed to differences in biologic responses to such gross environmental factors as water depth and clarity, and energy levels. At any one locality, gross aspects of the paleoenvironments are assumed to have been more uniform. Significant differences among bioherms at any one locality may have resulted from patchy distribution of species populations, differential preservation and other factors.

Detecting Statistically Significant Communities of Triangle Motifs in Undirected Networks

Science.gov (United States)

2016-04-26

Systems, Statistics & Management Science, University of Alabama, USA. 1 DISTRIBUTION A: Distribution approved for public release. Contents 1 Summary 5...13 5 Application to Real Networks 18 5.1 2012 FBS Football Schedule Network... football schedule network. . . . . . . . . . . . . . . . . . . . . . 21 14 Stem plot of degree-ordered vertices versus the degree for college football

Statistical significant changes in ground thermal conditions of alpine Austria during the last decade

Science.gov (United States)

Kellerer-Pirklbauer, Andreas

2016-04-01

Longer data series (e.g. >10 a) of ground temperatures in alpine regions are helpful to improve the understanding regarding the effects of present climate change on distribution and thermal characteristics of seasonal frost- and permafrost-affected areas. Beginning in 2004 - and more intensively since 2006 - a permafrost and seasonal frost monitoring network was established in Central and Eastern Austria by the University of Graz. This network consists of c.60 ground temperature (surface and near-surface) monitoring sites which are located at 1922-3002 m a.s.l., at latitude 46°55'-47°22'N and at longitude 12°44'-14°41'E. These data allow conclusions about general ground thermal conditions, potential permafrost occurrence, trend during the observation period, and regional pattern of changes. Calculations and analyses of several different temperature-related parameters were accomplished. At an annual scale a region-wide statistical significant warming during the observation period was revealed by e.g. an increase in mean annual temperature values (mean, maximum) or the significant lowering of the surface frost number (F+). At a seasonal scale no significant trend of any temperature-related parameter was in most cases revealed for spring (MAM) and autumn (SON). Winter (DJF) shows only a weak warming. In contrast, the summer (JJA) season reveals in general a significant warming as confirmed by several different temperature-related parameters such as e.g. mean seasonal temperature, number of thawing degree days, number of freezing degree days, or days without night frost. On a monthly basis August shows the statistically most robust and strongest warming of all months, although regional differences occur. Despite the fact that the general ground temperature warming during the last decade is confirmed by the field data in the study region, complications in trend analyses arise by temperature anomalies (e.g. warm winter 2006/07) or substantial variations in the winter

Conducting tests for statistically significant differences using forest inventory data

Science.gov (United States)

James A. Westfall; Scott A. Pugh; John W. Coulston

2013-01-01

Many forest inventory and monitoring programs are based on a sample of ground plots from which estimates of forest resources are derived. In addition to evaluating metrics such as number of trees or amount of cubic wood volume, it is often desirable to make comparisons between resource attributes. To properly conduct statistical tests for differences, it is imperative...

The distribution of P-values in medical research articles suggested selective reporting associated with statistical significance.

Science.gov (United States)

Perneger, Thomas V; Combescure, Christophe

2017-07-01

Published P-values provide a window into the global enterprise of medical research. The aim of this study was to use the distribution of published P-values to estimate the relative frequencies of null and alternative hypotheses and to seek irregularities suggestive of publication bias. This cross-sectional study included P-values published in 120 medical research articles in 2016 (30 each from the BMJ, JAMA, Lancet, and New England Journal of Medicine). The observed distribution of P-values was compared with expected distributions under the null hypothesis (i.e., uniform between 0 and 1) and the alternative hypothesis (strictly decreasing from 0 to 1). P-values were categorized according to conventional levels of statistical significance and in one-percent intervals. Among 4,158 recorded P-values, 26.1% were highly significant (P values values equal to 1, and (3) about twice as many P-values less than 0.05 compared with those more than 0.05. The latter finding was seen in both randomized trials and observational studies, and in most types of analyses, excepting heterogeneity tests and interaction tests. Under plausible assumptions, we estimate that about half of the tested hypotheses were null and the other half were alternative. This analysis suggests that statistical tests published in medical journals are not a random sample of null and alternative hypotheses but that selective reporting is prevalent. In particular, significant results are about twice as likely to be reported as nonsignificant results. Copyright © 2017 Elsevier Inc. All rights reserved.

Generalized $L-, M-$, and $R$-Statistics

OpenAIRE

Serfling, Robert J.

1984-01-01

A class of statistics generalizing $U$-statistics and $L$-statistics, and containing other varieties of statistic as well, such as trimmed $U$-statistics, is studied. Using the differentiable statistical function approach, differential approximations are obtained and the influence curves of these generalized $L$-statistics are derived. These results are employed to establish asymptotic normality for such statistics. Parallel generalizations of $M$- and $R$-statistics are noted. Strong converg...

THE SIGNIFICANCE OF INTERCULTURAL COMPETENCE IN CROSS-CULTURAL COMMUNICATION

Directory of Open Access Journals (Sweden)

Jadranka Zlomislić

2016-12-01

Full Text Available The aim of this study is to explore the influence of education and additional factors influencing students’ awareness of intercultural differences. For the purposes of this research assessment was carried out with regard to their role in promoting cultural awareness and facing cross-cultural challenges posed by unfamiliar cross-cultural contexts. Cultural education is presumed to be a key factor for achieving a significant increase of cultural sensitivity and cultural awareness in order to ensure successful cross-cultural communication and increase mobility of students/working professionals. For this study, it was assumed that the cultural awareness of students increases due to the courses they take and their overall study experience. A special questionnaire was developed for the purposes of this research, and the obtained results were statistically analyzed with the help of descriptive statistics, the non-parametric chi-square test, and the Mann-Whitney test. The research has shown that intercultural competence has a statistically significant positive effect on the readiness of students to participate in study and work programs abroad. Thus, it is mandatory that foreign language competence as well as intercultural competence be a priority of the curriculum if we are to increase the number of highly educated experts who will be capable to compete successfully as students or professionals in all fields and all cultural areas. If we recognize that globalization has made the world a global village, we all need the intercultural competence to successfully live in it.

Factors Influencing of Social Conflict

Directory of Open Access Journals (Sweden)

Suwandi Sumartias

2013-07-01

Full Text Available Social conflicts that occur in several areas in Indonesia lately, one of them is caused by the weakness of law certainty. This is feared to threaten the integration of the Republic of Indonesia. This study aims to determine the factors that affect social conflict in Manis Lor village in Kuningan district. The method used the explanatory quantitative methods, the statistical test Path Analysis. The study population was a formal and informal community leaders (village chief, clergy, and youth, and the people who involved in a conflict in Manis Lor village Kuningan regency. The result shows a There is no significant influence between social identity factors with social conflict anarchist. b There is significant influence between socio-economic factors with social conflict anarchists. c There is no significant influence between the credibility factor anarchist leaders with social conflict. d There is no significant influence between the motive factor with anarchist social conflict. e There is significant influence between personality factors/beliefs with anarchist social conflict. f There is significant influence of behavioral factors anarchist communication with social conflict.

Influence of image reconstruction methods on statistical parametric mapping of brain PET images

International Nuclear Information System (INIS)

Yin Dayi; Chen Yingmao; Yao Shulin; Shao Mingzhe; Yin Ling; Tian Jiahe; Cui Hongyan

2007-01-01

Objective: Statistic parametric mapping (SPM) was widely recognized as an useful tool in brain function study. The aim of this study was to investigate if imaging reconstruction algorithm of PET images could influence SPM of brain. Methods: PET imaging of whole brain was performed in six normal volunteers. Each volunteer had two scans with true and false acupuncturing. The PET scans were reconstructed using ordered subsets expectation maximization (OSEM) and filtered back projection (FBP) with 3 varied parameters respectively. The images were realigned, normalized and smoothed using SPM program. The difference between true and false acupuncture scans was tested using a matched pair t test at every voxel. Results: (1) SPM corrected multiple comparison (P corrected uncorrected <0.001): SPM derived from the images with different reconstruction method were different. The largest difference, in number and position of the activated voxels, was noticed between FBP and OSEM re- construction algorithm. Conclusions: The method of PET image reconstruction could influence the results of SPM uncorrected multiple comparison. Attention should be paid when the conclusion was drawn using SPM uncorrected multiple comparison. (authors)

Effects of quantum coherence on work statistics

Science.gov (United States)

Xu, Bao-Ming; Zou, Jian; Guo, Li-Sha; Kong, Xiang-Mu

2018-05-01

In the conventional two-point measurement scheme of quantum thermodynamics, quantum coherence is destroyed by the first measurement. But as we know the coherence really plays an important role in the quantum thermodynamics process, and how to describe the work statistics for a quantum coherent process is still an open question. In this paper, we use the full counting statistics method to investigate the effects of quantum coherence on work statistics. First, we give a general discussion and show that for a quantum coherent process, work statistics is very different from that of the two-point measurement scheme, specifically the average work is increased or decreased and the work fluctuation can be decreased by quantum coherence, which strongly depends on the relative phase, the energy level structure, and the external protocol. Then, we concretely consider a quenched one-dimensional transverse Ising model and show that quantum coherence has a more significant influence on work statistics in the ferromagnetism regime compared with that in the paramagnetism regime, so that due to the presence of quantum coherence the work statistics can exhibit the critical phenomenon even at high temperature.

Sigsearch: a new term for post hoc unplanned search for statistically significant relationships with the intent to create publishable findings.

Science.gov (United States)

Hashim, Muhammad Jawad

2010-09-01

Post-hoc secondary data analysis with no prespecified hypotheses has been discouraged by textbook authors and journal editors alike. Unfortunately no single term describes this phenomenon succinctly. I would like to coin the term "sigsearch" to define this practice and bring it within the teaching lexicon of statistics courses. Sigsearch would include any unplanned, post-hoc search for statistical significance using multiple comparisons of subgroups. It would also include data analysis with outcomes other than the prespecified primary outcome measure of a study as well as secondary data analyses of earlier research.

The statistical mind in modern society. The Netherlands 1850-1940. Volume II: statistics and scientific work

NARCIS (Netherlands)

Stamhuis, I.H.; Klep, P.M.M.; Maarseveen, J.G.S.J. van

2008-01-01

In the period 1850-1940 statistics developed as a new combination of theory and practice. A wide range of phenomena were looked at in a novel way and this statistical mindset had a pervasive influence in contemporary society. This development of statistics is closely interlinked with the process of

Influence of peer review on the reporting of primary outcome(s) and statistical analyses of randomised trials.

Science.gov (United States)

Hopewell, Sally; Witt, Claudia M; Linde, Klaus; Icke, Katja; Adedire, Olubusola; Kirtley, Shona; Altman, Douglas G

2018-01-11

Selective reporting of outcomes in clinical trials is a serious problem. We aimed to investigate the influence of the peer review process within biomedical journals on reporting of primary outcome(s) and statistical analyses within reports of randomised trials. Each month, PubMed (May 2014 to April 2015) was searched to identify primary reports of randomised trials published in six high-impact general and 12 high-impact specialty journals. The corresponding author of each trial was invited to complete an online survey asking authors about changes made to their manuscript as part of the peer review process. Our main outcomes were to assess: (1) the nature and extent of changes as part of the peer review process, in relation to reporting of the primary outcome(s) and/or primary statistical analysis; (2) how often authors followed these requests; and (3) whether this was related to specific journal or trial characteristics. Of 893 corresponding authors who were invited to take part in the online survey 258 (29%) responded. The majority of trials were multicentre (n = 191; 74%); median sample size 325 (IQR 138 to 1010). The primary outcome was clearly defined in 92% (n = 238), of which the direction of treatment effect was statistically significant in 49%. The majority responded (1-10 Likert scale) they were satisfied with the overall handling (mean 8.6, SD 1.5) and quality of peer review (mean 8.5, SD 1.5) of their manuscript. Only 3% (n = 8) said that the editor or peer reviewers had asked them to change or clarify the trial's primary outcome. However, 27% (n = 69) reported they were asked to change or clarify the statistical analysis of the primary outcome; most had fulfilled the request, the main motivation being to improve the statistical methods (n = 38; 55%) or avoid rejection (n = 30; 44%). Overall, there was little association between authors being asked to make this change and the type of journal, intervention, significance of the

Significant influence of the primary liver disease on the outcomes of hepatic retransplantation.

LENUS (Irish Health Repository)

Qasim, A

2012-02-01

BACKGROUND: There are many indications for hepatic retransplantation. AIM: To identify factors influencing retransplantation needs and outcomes. PATIENTS AND METHODS: Retransplantation records from January 1993 to March 2005 were analysed. Patient and disease characteristics and survival outcomes for retransplantation were compared between various groups. RESULTS: Totally, 286 primary and 42 hepatic retransplantations were performed. Retransplantation indications included primary sclerosing cholangitis (PSC), primary biliary cirrhosis, chronic hepatitis C (HCV), chronic active hepatitis (CAH), and alcohol-related disease. Mean follow-up post-retransplantation was 31 +\\/- 9 months. Actuarial patient survival at 3 months, 1 year, 3 years, 5 years, and at the end of study was 71.4, 69, 59.5, 54.7, and 50%, respectively. Early and late retransplantation had 1-year survival of 73 and 68.5%, respectively. Retransplantation need was significantly higher for PSC, HCV, and CAH. CONCLUSIONS: Hepatic retransplantation remains a successful salvage option for transplant complications; however, its need is significantly influenced by the primary liver disease.

Race, Sex, and Their Influences on Introductory Statistics Education

Science.gov (United States)

van Es, Cindy; Weaver, Michelle M.

2018-01-01

The Survey of Attitudes Toward Statistics or SATS was administered for three consecutive years to students in an Introductory Statistics course at Cornell University. Questions requesting demographic information and expected final course grade were added. Responses were analyzed to investigate possible differences between sexes and racial/ethnic…

Intelligent system for statistically significant expertise knowledge on the basis of the model of self-organizing nonequilibrium dissipative system

Directory of Open Access Journals (Sweden)

E. A. Tatokchin

2017-01-01

Full Text Available Development of the modern educational technologies caused by broad introduction of comput-er testing and development of distant forms of education does necessary revision of methods of an examination of pupils. In work it was shown, need transition to mathematical criteria, exami-nations of knowledge which are deprived of subjectivity. In article the review of the problems arising at realization of this task and are offered approaches for its decision. The greatest atten-tion is paid to discussion of a problem of objective transformation of rated estimates of the ex-pert on to the scale estimates of the student. In general, the discussion this question is was con-cluded that the solution to this problem lies in the creation of specialized intellectual systems. The basis for constructing intelligent system laid the mathematical model of self-organizing nonequilibrium dissipative system, which is a group of students. This article assumes that the dissipative system is provided by the constant influx of new test items of the expert and non-equilibrium – individual psychological characteristics of students in the group. As a result, the system must self-organize themselves into stable patterns. This patern will allow for, relying on large amounts of data, get a statistically significant assessment of student. To justify the pro-posed approach in the work presents the data of the statistical analysis of the results of testing a large sample of students (> 90. Conclusions from this statistical analysis allowed to develop intelligent system statistically significant examination of student performance. It is based on data clustering algorithm (k-mean for the three key parameters. It is shown that this approach allows you to create of the dynamics and objective expertise evaluation.

The Importance of Integrating Clinical Relevance and Statistical Significance in the Assessment of Quality of Care--Illustrated Using the Swedish Stroke Register.

Directory of Open Access Journals (Sweden)

Anita Lindmark

Full Text Available When profiling hospital performance, quality inicators are commonly evaluated through hospital-specific adjusted means with confidence intervals. When identifying deviations from a norm, large hospitals can have statistically significant results even for clinically irrelevant deviations while important deviations in small hospitals can remain undiscovered. We have used data from the Swedish Stroke Register (Riksstroke to illustrate the properties of a benchmarking method that integrates considerations of both clinical relevance and level of statistical significance.The performance measure used was case-mix adjusted risk of death or dependency in activities of daily living within 3 months after stroke. A hospital was labeled as having outlying performance if its case-mix adjusted risk exceeded a benchmark value with a specified statistical confidence level. The benchmark was expressed relative to the population risk and should reflect the clinically relevant deviation that is to be detected. A simulation study based on Riksstroke patient data from 2008-2009 was performed to investigate the effect of the choice of the statistical confidence level and benchmark value on the diagnostic properties of the method.Simulations were based on 18,309 patients in 76 hospitals. The widely used setting, comparing 95% confidence intervals to the national average, resulted in low sensitivity (0.252 and high specificity (0.991. There were large variations in sensitivity and specificity for different requirements of statistical confidence. Lowering statistical confidence improved sensitivity with a relatively smaller loss of specificity. Variations due to different benchmark values were smaller, especially for sensitivity. This allows the choice of a clinically relevant benchmark to be driven by clinical factors without major concerns about sufficiently reliable evidence.The study emphasizes the importance of combining clinical relevance and level of statistical

The Importance of Integrating Clinical Relevance and Statistical Significance in the Assessment of Quality of Care--Illustrated Using the Swedish Stroke Register.

Science.gov (United States)

Lindmark, Anita; van Rompaye, Bart; Goetghebeur, Els; Glader, Eva-Lotta; Eriksson, Marie

2016-01-01

When profiling hospital performance, quality inicators are commonly evaluated through hospital-specific adjusted means with confidence intervals. When identifying deviations from a norm, large hospitals can have statistically significant results even for clinically irrelevant deviations while important deviations in small hospitals can remain undiscovered. We have used data from the Swedish Stroke Register (Riksstroke) to illustrate the properties of a benchmarking method that integrates considerations of both clinical relevance and level of statistical significance. The performance measure used was case-mix adjusted risk of death or dependency in activities of daily living within 3 months after stroke. A hospital was labeled as having outlying performance if its case-mix adjusted risk exceeded a benchmark value with a specified statistical confidence level. The benchmark was expressed relative to the population risk and should reflect the clinically relevant deviation that is to be detected. A simulation study based on Riksstroke patient data from 2008-2009 was performed to investigate the effect of the choice of the statistical confidence level and benchmark value on the diagnostic properties of the method. Simulations were based on 18,309 patients in 76 hospitals. The widely used setting, comparing 95% confidence intervals to the national average, resulted in low sensitivity (0.252) and high specificity (0.991). There were large variations in sensitivity and specificity for different requirements of statistical confidence. Lowering statistical confidence improved sensitivity with a relatively smaller loss of specificity. Variations due to different benchmark values were smaller, especially for sensitivity. This allows the choice of a clinically relevant benchmark to be driven by clinical factors without major concerns about sufficiently reliable evidence. The study emphasizes the importance of combining clinical relevance and level of statistical confidence when

Estimates of statistical significance for comparison of individual positions in multiple sequence alignments

Directory of Open Access Journals (Sweden)

Sadreyev Ruslan I

2004-08-01

Full Text Available Abstract Background Profile-based analysis of multiple sequence alignments (MSA allows for accurate comparison of protein families. Here, we address the problems of detecting statistically confident dissimilarities between (1 MSA position and a set of predicted residue frequencies, and (2 between two MSA positions. These problems are important for (i evaluation and optimization of methods predicting residue occurrence at protein positions; (ii detection of potentially misaligned regions in automatically produced alignments and their further refinement; and (iii detection of sites that determine functional or structural specificity in two related families. Results For problems (1 and (2, we propose analytical estimates of P-value and apply them to the detection of significant positional dissimilarities in various experimental situations. (a We compare structure-based predictions of residue propensities at a protein position to the actual residue frequencies in the MSA of homologs. (b We evaluate our method by the ability to detect erroneous position matches produced by an automatic sequence aligner. (c We compare MSA positions that correspond to residues aligned by automatic structure aligners. (d We compare MSA positions that are aligned by high-quality manual superposition of structures. Detected dissimilarities reveal shortcomings of the automatic methods for residue frequency prediction and alignment construction. For the high-quality structural alignments, the dissimilarities suggest sites of potential functional or structural importance. Conclusion The proposed computational method is of significant potential value for the analysis of protein families.

Statistical analysis of dragline monitoring data

Energy Technology Data Exchange (ETDEWEB)

Mirabediny, H.; Baafi, E.Y. [University of Tehran, Tehran (Iran)

1998-07-01

Dragline monitoring systems are normally the best tool used to collect data on the machine performance and operational parameters of a dragline operation. This paper discusses results of a time study using data from a dragline monitoring system captured over a four month period. Statistical summaries of the time study in terms of average values, standard deviation and frequency distributions showed that the mode of operation and the geological conditions have a significant influence on the dragline performance parameters. 6 refs., 14 figs., 3 tabs.

Test the Overall Significance of p-values by Using Joint Tail Probability of Ordered p-values as Test Statistic

NARCIS (Netherlands)

Fang, Yongxiang; Wit, Ernst

2008-01-01

Fisher’s combined probability test is the most commonly used method to test the overall significance of a set independent p-values. However, it is very obviously that Fisher’s statistic is more sensitive to smaller p-values than to larger p-value and a small p-value may overrule the other p-values

Significant-Loophole-Free Test of Bell's Theorem with Entangled Photons.

Science.gov (United States)

Giustina, Marissa; Versteegh, Marijn A M; Wengerowsky, Sören; Handsteiner, Johannes; Hochrainer, Armin; Phelan, Kevin; Steinlechner, Fabian; Kofler, Johannes; Larsson, Jan-Åke; Abellán, Carlos; Amaya, Waldimar; Pruneri, Valerio; Mitchell, Morgan W; Beyer, Jörn; Gerrits, Thomas; Lita, Adriana E; Shalm, Lynden K; Nam, Sae Woo; Scheidl, Thomas; Ursin, Rupert; Wittmann, Bernhard; Zeilinger, Anton

2015-12-18

Local realism is the worldview in which physical properties of objects exist independently of measurement and where physical influences cannot travel faster than the speed of light. Bell's theorem states that this worldview is incompatible with the predictions of quantum mechanics, as is expressed in Bell's inequalities. Previous experiments convincingly supported the quantum predictions. Yet, every experiment requires assumptions that provide loopholes for a local realist explanation. Here, we report a Bell test that closes the most significant of these loopholes simultaneously. Using a well-optimized source of entangled photons, rapid setting generation, and highly efficient superconducting detectors, we observe a violation of a Bell inequality with high statistical significance. The purely statistical probability of our results to occur under local realism does not exceed 3.74×10^{-31}, corresponding to an 11.5 standard deviation effect.

To what extent does variability of historical rainfall series influence extreme event statistics of sewer system surcharge and overflows?

DEFF Research Database (Denmark)

Schaarup-Jensen, Kjeld; Rasmussen, Michael R.; Thorndahl, Søren

2008-01-01

In urban drainage modeling long term extreme statistics has become an important basis for decision-making e.g. in connection with renovation projects. Therefore it is of great importance to minimize the uncertainties concerning long term prediction of maximum water levels and combined sewer...... overflow (CSO) in drainage systems. These uncertainties originate from large uncertainties regarding rainfall inputs, parameters, and assessment of return periods. This paper investigates how the choice of rainfall time series influences the extreme events statistics of max water levels in manholes and CSO...... gauges are located at a distance of max 20 kilometers from the catchment. All gauges are included in the Danish national rain gauge system which was launched in 1976. The paper describes to what extent the extreme events statistics based on these 9 series diverge from each other and how this diversity...

To what extent does variability of historical rainfall series influence extreme event statistics of sewer system surcharge and overflows?

DEFF Research Database (Denmark)

Schaarup-Jensen, Kjeld; Rasmussen, Michael R.; Thorndahl, Søren

2009-01-01

In urban drainage modelling long term extreme statistics has become an important basis for decision-making e.g. in connection with renovation projects. Therefore it is of great importance to minimize the uncertainties concerning long term prediction of maximum water levels and combined sewer...... overflow (CSO) in drainage systems. These uncertainties originate from large uncertainties regarding rainfall inputs, parameters, and assessment of return periods. This paper investigates how the choice of rainfall time series influences the extreme events statistics of max water levels in manholes and CSO...... gauges are located at a distance of max 20 kilometers from the catchment. All gauges are included in the Danish national rain gauge system which was launched in 1976. The paper describes to what extent the extreme events statistics based on these 9 series diverge from each other and how this diversity...

Managing Macroeconomic Risks by Using Statistical Simulation

Directory of Open Access Journals (Sweden)

Merkaš Zvonko

2017-06-01

Full Text Available The paper analyzes the possibilities of using statistical simulation in the macroeconomic risks measurement. At the level of the whole world, macroeconomic risks are, due to the excessive imbalance, significantly increased. Using analytical statistical methods and Monte Carlo simulation, the authors interpret the collected data sets, compare and analyze them in order to mitigate potential risks. The empirical part of the study is a qualitative case study that uses statistical methods and Monte Carlo simulation for managing macroeconomic risks, which is the central theme of this work. Application of statistical simulation is necessary because the system, for which it is necessary to specify the model, is too complex for an analytical approach. The objective of the paper is to point out the previous need for consideration of significant macroeconomic risks, particularly in terms of the number of the unemployed in the society, the movement of gross domestic product and the country’s credit rating, and the use of data previously processed by statistical methods, through statistical simulation, to analyze the existing model of managing the macroeconomic risks and suggest elements for a management model development that will allow, with the lowest possible probability and consequences, the emergence of the recent macroeconomic risks. The stochastic characteristics of the system, defined by random variables as input values defined by probability distributions, require the performance of a large number of iterations on which to record the output of the model and calculate the mathematical expectations. The paper expounds the basic procedures and techniques of discrete statistical simulation applied to systems that can be characterized by a number of events which represent a set of circumstances that have caused a change in the system’s state and the possibility of its application in the field of assessment of macroeconomic risks. The method has no

Why Wait? The Influence of Academic Self-Regulation, Intrinsic Motivation, and Statistics Anxiety on Procrastination in Online Statistics

Science.gov (United States)

Dunn, Karee

2014-01-01

Online graduate education programs are expanding rapidly. Many of these programs require a statistics course, resulting in an increasing need for online statistics courses. The study reported here grew from experiences teaching online, graduate statistics courses. In seeking answers on how to improve this class, I discovered that research has yet…

Technical issues relating to the statistical parametric mapping of brain SPECT studies

International Nuclear Information System (INIS)

Hatton, R.L.; Cordato, N.; Hutton, B.F.; Lau, Y.H.; Evans, S.G.

2000-01-01

Full text: Statistical Parametric Mapping (SPM) is a software tool designed for the statistical analysis of functional neuro images, specifically Positron Emission Tomography and functional Magnetic Resonance Imaging, and more recently SPECT. This review examines some problems associated with the analysis of SPECT. A comparison of a patient group with normal studies revealed factors that could influence results, some that commonly occur, others that require further exploration. To optimise the differences between two groups of subjects, both spatial variability and differences in global activity must be minimised. The choice and effectiveness of co registration method and approach to normalisation of activity concentration can affect the optimisation. A small number of subject scans were identified as possessing truncated data resulting in edge effects that could adversely influence the analysis. Other problems included unusual areas of significance possibly related to reconstruction methods and the geometry associated with nonparallel collimators. Areas of extra cerebral significance are a point of concern - and may result from scatter effects, or mis registration. Difficulties in patient positioning, due to postural limitations, can lead to resolution differences. SPM has been used to assess areas of statistical significance arising from these technical factors, as opposed to areas of true clinical significance when comparing subject groups. This contributes to a better understanding of the effects of technical factors so that these may be eliminated, minimised, or incorporated in the study design. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

Statistically significant dependence of the Xaa-Pro peptide bond conformation on secondary structure and amino acid sequence

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Leitner Dietmar

2005-04-01

Full Text Available Abstract Background A reliable prediction of the Xaa-Pro peptide bond conformation would be a useful tool for many protein structure calculation methods. We have analyzed the Protein Data Bank and show that the combined use of sequential and structural information has a predictive value for the assessment of the cis versus trans peptide bond conformation of Xaa-Pro within proteins. For the analysis of the data sets different statistical methods such as the calculation of the Chou-Fasman parameters and occurrence matrices were used. Furthermore we analyzed the relationship between the relative solvent accessibility and the relative occurrence of prolines in the cis and in the trans conformation. Results One of the main results of the statistical investigations is the ranking of the secondary structure and sequence information with respect to the prediction of the Xaa-Pro peptide bond conformation. We observed a significant impact of secondary structure information on the occurrence of the Xaa-Pro peptide bond conformation, while the sequence information of amino acids neighboring proline is of little predictive value for the conformation of this bond. Conclusion In this work, we present an extensive analysis of the occurrence of the cis and trans proline conformation in proteins. Based on the data set, we derived patterns and rules for a possible prediction of the proline conformation. Upon adoption of the Chou-Fasman parameters, we are able to derive statistically relevant correlations between the secondary structure of amino acid fragments and the Xaa-Pro peptide bond conformation.

CONFIDENCE LEVELS AND/VS. STATISTICAL HYPOTHESIS TESTING IN STATISTICAL ANALYSIS. CASE STUDY

Directory of Open Access Journals (Sweden)

ILEANA BRUDIU

2009-05-01

Full Text Available Estimated parameters with confidence intervals and testing statistical assumptions used in statistical analysis to obtain conclusions on research from a sample extracted from the population. Paper to the case study presented aims to highlight the importance of volume of sample taken in the study and how this reflects on the results obtained when using confidence intervals and testing for pregnant. If statistical testing hypotheses not only give an answer "yes" or "no" to some questions of statistical estimation using statistical confidence intervals provides more information than a test statistic, show high degree of uncertainty arising from small samples and findings build in the "marginally significant" or "almost significant (p very close to 0.05.

The statistical mind in modern society. The Netherlands 1850-1940. Volume I: official Statistics, social progress and modern enterprise

NARCIS (Netherlands)

Maarseveen, J.G.S.J. van; Klep, P.M.M.; Stamhuis, I.H.

2008-01-01

In the period 1850-1940 statistics developed as a new combination of theory and practice. A wide range of phenomena were looked at in a novel way and this statistical mindset had a pervasive influence in contemporary society. This development of statistics is closely interlinked with the process of

Sb2Te3 and Its Superlattices: Optimization by Statistical Design.

Science.gov (United States)

Behera, Jitendra K; Zhou, Xilin; Ranjan, Alok; Simpson, Robert E

2018-05-02

The objective of this work is to demonstrate the usefulness of fractional factorial design for optimizing the crystal quality of chalcogenide van der Waals (vdW) crystals. We statistically analyze the growth parameters of highly c axis oriented Sb 2 Te 3 crystals and Sb 2 Te 3 -GeTe phase change vdW heterostructured superlattices. The statistical significance of the growth parameters of temperature, pressure, power, buffer materials, and buffer layer thickness was found by fractional factorial design and response surface analysis. Temperature, pressure, power, and their second-order interactions are the major factors that significantly influence the quality of the crystals. Additionally, using tungsten rather than molybdenum as a buffer layer significantly enhances the crystal quality. Fractional factorial design minimizes the number of experiments that are necessary to find the optimal growth conditions, resulting in an order of magnitude improvement in the crystal quality. We highlight that statistical design of experiment methods, which is more commonly used in product design, should be considered more broadly by those designing and optimizing materials.

The Influence of Statistical versus Exemplar Appeals on Indian Adults' Health Intentions: An Investigation of Direct Effects and Intervening Persuasion Processes.

Science.gov (United States)

McKinley, Christopher J; Limbu, Yam; Jayachandran, C N

2017-04-01

In two separate investigations, we examined the persuasive effectiveness of statistical versus exemplar appeals on Indian adults' smoking cessation and mammography screening intentions. To more comprehensively address persuasion processes, we explored whether message response and perceived message effectiveness functioned as antecedents to persuasive effects. Results showed that statistical appeals led to higher levels of health intentions than exemplar appeals. In addition, findings from both studies indicated that statistical appeals stimulated more attention and were perceived as more effective than anecdotal accounts. Among male smokers, statistical appeals also generated greater cognitive processing than exemplar appeals. Subsequent mediation analyses revealed that message response and perceived message effectiveness fully carried the influence of appeal format on health intentions. Given these findings, future public health initiatives conducted among similar populations should design messages that include substantive factual information while ensuring that this content is perceived as credible and valuable.

The Significance of the Influence of the CME Deflection in Interplanetary Space on the CME Arrival at Earth

Science.gov (United States)

Zhuang, Bin; Wang, Yuming; Shen, Chenglong; Liu, Siqing; Wang, Jingjing; Pan, Zonghao; Li, Huimin; Liu, Rui

2017-08-01

As one of the most violent astrophysical phenomena, coronal mass ejections (CMEs) have strong potential space weather effects. However, not all Earth-directed CMEs encounter the Earth and produce geo-effects. One reason is the deflected propagation of CMEs in interplanetary space. Although there have been several case studies clearly showing such deflections, it has not yet been statistically assessed how significantly the deflected propagation would influence the CME’s arrival at Earth. We develop an integrated CME-arrival forecasting (iCAF) system, assembling the modules of CME detection, three-dimensional (3D) parameter derivation, and trajectory reconstruction to predict whether or not a CME arrives at Earth, and we assess the deflection influence on the CME-arrival forecasting. The performance of iCAF is tested by comparing the two-dimensional (2D) parameters with those in the Coordinated Data Analysis Workshop (CDAW) Data Center catalog, comparing the 3D parameters with those of the gradual cylindrical shell model, and estimating the success rate of the CME Earth-arrival predictions. It is found that the 2D parameters provided by iCAF and the CDAW catalog are consistent with each other, and the 3D parameters derived by the ice cream cone model based on single-view observations are acceptable. The success rate of the CME-arrival predictions by iCAF with deflection considered is about 82%, which is 19% higher than that without deflection, indicating the importance of the CME deflection for providing a reliable forecasting. Furthermore, iCAF is a worthwhile project since it is a completely automatic system with deflection taken into account.

Significance and influence of the ambient temperature as a rate ...

Indian Academy of Sciences (India)

Unknown

The results obtained show that the influence of the studied factor is more complex showing an acceleration effect ... ment, the related data in the literature are very sporadic and limited. .... individual function relations expressing the influence of.

The effects of dynamics on statistical emission

International Nuclear Information System (INIS)

Friedman, W.A.

1989-01-01

The dynamical processes which occur during the disassembly of an excited nuclear system influence predictions arising from a statistical treatment of the decay of that system. Changes, during the decay period, in such collective properties as angular momentum, density, and kinetic energy of the emitting source affect both the mass and energy spectra of the emitted fragments. This influence will be examined. The author will explore the influence of nuclear compressibility on the decay process, in order to determine what information can be learned about this property from the products of decay. He will compare the relationship between disparate scenarios of decay: a succession of binary decays, each governed by statistics; and a full microcanonical distribution at a single freeze-out density. The author hopes to learn from the general nature of these two statistical predictions when one or the other might be more realistic, and what signatures resulting from the two models might be used to determine which accounts best for specific experimental results

Influence of Significant Others on High School Students' Expectancies of Success and Task Value in Physical Education

Science.gov (United States)

Williams, Skip M.; Weiss, Windee

2018-01-01

This study examined the perceived influence of significant others' beliefs on students' expectancies of success and task value in physical education (PE). PE students (N = 231) between Grades 9 and 12 participated. Multiple regressions examined the influence of perceived parents', teachers', and classmates' beliefs on students' ability…

Pretreatment factors significantly influence quality of life in cancer patients: A Radiation Therapy Oncology Group (RTOG) analysis

International Nuclear Information System (INIS)

Movsas, Benjamin; Scott, Charles; Watkins-Bruner, Deborah

2006-01-01

Purpose The purpose of this analysis was to assess the impact of pretreatment factors on quality of life (QOL) in cancer patients. Methods and Materials Pretreatment QOL (via Functional Assessment of Cancer Therapy [FACT], version 2) was obtained in 1,428 patients in several prospective Radiation Therapy Oncology Group (RTOG) trials including nonmetastatic head-and-neck (n = 1139), esophageal (n = 174), lung (n = 51), rectal (n = 47), and prostate (n = 17) cancer patients. Clinically meaningful differences between groups were defined as a difference of 1 standard error of measurement (SEM). Results The mean FACT score for all patients was 86 (20.7-112) with SEM of 5.3. Statistically significant differences in QOL were observed based on age, race, Karnofsky Performance Status, marital status, education level, income level, and employment status, but not by gender or primary site. Using the SEM, there were clinically meaningful differences between patients ≤50 years vs. ≥65 years. Hispanics had worse QOL than whites. FACT increased linearly with higher Karnofsky Performance Status and income levels. Married patients (or live-in relationships) had a better QOL than single, divorced, or widowed patients. College graduates had better QOL than those with less education. Conclusion Most pretreatment factors meaningfully influenced baseline QOL. The potentially devastating impact of a cancer diagnosis, particularly in young and minority patients, must be addressed

Determining coding CpG islands by identifying regions significant for pattern statistics on Markov chains.

Science.gov (United States)

Singer, Meromit; Engström, Alexander; Schönhuth, Alexander; Pachter, Lior

2011-09-23

Recent experimental and computational work confirms that CpGs can be unmethylated inside coding exons, thereby showing that codons may be subjected to both genomic and epigenomic constraint. It is therefore of interest to identify coding CpG islands (CCGIs) that are regions inside exons enriched for CpGs. The difficulty in identifying such islands is that coding exons exhibit sequence biases determined by codon usage and constraints that must be taken into account. We present a method for finding CCGIs that showcases a novel approach we have developed for identifying regions of interest that are significant (with respect to a Markov chain) for the counts of any pattern. Our method begins with the exact computation of tail probabilities for the number of CpGs in all regions contained in coding exons, and then applies a greedy algorithm for selecting islands from among the regions. We show that the greedy algorithm provably optimizes a biologically motivated criterion for selecting islands while controlling the false discovery rate. We applied this approach to the human genome (hg18) and annotated CpG islands in coding exons. The statistical criterion we apply to evaluating islands reduces the number of false positives in existing annotations, while our approach to defining islands reveals significant numbers of undiscovered CCGIs in coding exons. Many of these appear to be examples of functional epigenetic specialization in coding exons.

A quantitative analysis of factors influencing the professional longevity of high school science teachers in Florida

Science.gov (United States)

Ridgley, James Alexander, Jr.

This dissertation is an exploratory quantitative analysis of various independent variables to determine their effect on the professional longevity (years of service) of high school science teachers in the state of Florida for the academic years 2011-2012 to 2013-2014. Data are collected from the Florida Department of Education, National Center for Education Statistics, and the National Assessment of Educational Progress databases. The following research hypotheses are examined: H1 - There are statistically significant differences in Level 1 (teacher variables) that influence the professional longevity of a high school science teacher in Florida. H2 - There are statistically significant differences in Level 2 (school variables) that influence the professional longevity of a high school science teacher in Florida. H3 - There are statistically significant differences in Level 3 (district variables) that influence the professional longevity of a high school science teacher in Florida. H4 - When tested in a hierarchical multiple regression, there are statistically significant differences in Level 1, Level 2, or Level 3 that influence the professional longevity of a high school science teacher in Florida. The professional longevity of a Floridian high school science teacher is the dependent variable. The independent variables are: (Level 1) a teacher's sex, age, ethnicity, earned degree, salary, number of schools taught in, migration count, and various years of service in different areas of education; (Level 2) a school's geographic location, residential population density, average class size, charter status, and SES; and (Level 3) a school district's average SES and average spending per pupil. Statistical analyses of exploratory MLRs and a HMR are used to support the research hypotheses. The final results of the HMR analysis show a teacher's age, salary, earned degree (unknown, associate, and doctorate), and ethnicity (Hispanic and Native Hawaiian/Pacific Islander); a

The influence of bilingualism on statistical word learning.

Science.gov (United States)

Poepsel, Timothy J; Weiss, Daniel J

2016-07-01

Statistical learning is a fundamental component of language acquisition, yet to date, relatively few studies have examined whether these abilities differ in bilinguals. In the present study, we examine this issue by comparing English monolinguals with Chinese-English and English-Spanish bilinguals in a cross-situational statistical learning (CSSL) task. In Experiment 1, we assessed the ability of both monolinguals and bilinguals on a basic CSSL task that contained only one-to-one mappings. In Experiment 2, learners were asked to form both one-to-one and two-to-one mappings, and were tested at three points during familiarization. Overall, monolinguals and bilinguals did not differ in their learning of one-to-one mappings. However, bilinguals more quickly acquired two-to-one mappings, while also exhibiting greater proficiency than monolinguals. We conclude that the fundamental SL mechanism may not be affected by language experience, in accord with previous studies. However, when the input contains greater variability, bilinguals may be more prone to detecting the presence of multiple structures. Copyright © 2016 Elsevier B.V. All rights reserved.

Gene cluster statistics with gene families.

Science.gov (United States)

Raghupathy, Narayanan; Durand, Dannie

2009-05-01

Identifying genomic regions that descended from a common ancestor is important for understanding the function and evolution of genomes. In distantly related genomes, clusters of homologous gene pairs are evidence of candidate homologous regions. Demonstrating the statistical significance of such "gene clusters" is an essential component of comparative genomic analyses. However, currently there are no practical statistical tests for gene clusters that model the influence of the number of homologs in each gene family on cluster significance. In this work, we demonstrate empirically that failure to incorporate gene family size in gene cluster statistics results in overestimation of significance, leading to incorrect conclusions. We further present novel analytical methods for estimating gene cluster significance that take gene family size into account. Our methods do not require complete genome data and are suitable for testing individual clusters found in local regions, such as contigs in an unfinished assembly. We consider pairs of regions drawn from the same genome (paralogous clusters), as well as regions drawn from two different genomes (orthologous clusters). Determining cluster significance under general models of gene family size is computationally intractable. By assuming that all gene families are of equal size, we obtain analytical expressions that allow fast approximation of cluster probabilities. We evaluate the accuracy of this approximation by comparing the resulting gene cluster probabilities with cluster probabilities obtained by simulating a realistic, power-law distributed model of gene family size, with parameters inferred from genomic data. Surprisingly, despite the simplicity of the underlying assumption, our method accurately approximates the true cluster probabilities. It slightly overestimates these probabilities, yielding a conservative test. We present additional simulation results indicating the best choice of parameter values for data

Lipopolysaccharide significantly influences the hepatic triglyceride metabolism in growing pigs.

Science.gov (United States)

Liu, Zhiqing; Liu, Weifeng; Huang, Yanping; Guo, Jun; Zhao, Ruqian; Yang, Xiaojing

2015-06-30

In the practical commercial pig farms, inflammation is a perennial problem, yet most of studies on inflammation are focused on immune response. Actually, inflammation can induce body metabolism disorder which will finally influence animals' growth. In this study, we investigated the effect of acute inflammation on the triglyceride (TG) metabolism in the liver of growing pigs and the possible underlying mechanisms. Twelve male growing pigs were randomly divided into two groups, a control group (received saline) and a LPS group (intramuscular injected with 15 μg/kg LPS). Six hours after LPS injection, the pigs were euthanized and sampled. Biochemical indexes, inflammation factors, lipid metabolism related parameters and mitochondrial function were evaluated. The relationship between glucocorticoid receptor (GR) and the key enzymes of de novo lipogenesis were also investigated by chromatin immunoprecipitation assay (ChIP). LPS induced a serious inflammation in the liver of growing pigs proved by liver morphologic changes, the up-regulated plasma cortisol, tumor necrosis factor-α (TNF-α) content and gene expression of inflammation related genes in liver. For de novo lipogenesis, LPS significantly decreased the gene expression of fatty acid synthase (FAS), Acetyl-CoA carboxylase-1 (ACC-1) and Stearoyl-CoA desaturase-1 (SCD-1), and the protein expression of ACC-1 and SCD-1. For lipolysis, only the gene expression of adipose triglyceride lipase (ATGL) was decreased. LPS did nothing to the gene expression of hormone-sensitive lipase (HSL) and the lipolytic enzymes activities. For β-oxidation, LPS significantly increased the protein expression of CPT-1α, but the gene expression of mitochondrial DNA-encoded genes and the activities of mitochondrial complex IV and V demonstrated no obviously changes. Furthermore, ChIP results showed that LPS significantly decreased the level of GR binding to ACC-1 promoter. LPS infection has a profound impact on hepatic TG metabolism

P values in display items are ubiquitous and almost invariably significant: A survey of top science journals.

Science.gov (United States)

Cristea, Ioana Alina; Ioannidis, John P A

2018-01-01

P values represent a widely used, but pervasively misunderstood and fiercely contested method of scientific inference. Display items, such as figures and tables, often containing the main results, are an important source of P values. We conducted a survey comparing the overall use of P values and the occurrence of significant P values in display items of a sample of articles in the three top multidisciplinary journals (Nature, Science, PNAS) in 2017 and, respectively, in 1997. We also examined the reporting of multiplicity corrections and its potential influence on the proportion of statistically significant P values. Our findings demonstrated substantial and growing reliance on P values in display items, with increases of 2.5 to 14.5 times in 2017 compared to 1997. The overwhelming majority of P values (94%, 95% confidence interval [CI] 92% to 96%) were statistically significant. Methods to adjust for multiplicity were almost non-existent in 1997, but reported in many articles relying on P values in 2017 (Nature 68%, Science 48%, PNAS 38%). In their absence, almost all reported P values were statistically significant (98%, 95% CI 96% to 99%). Conversely, when any multiplicity corrections were described, 88% (95% CI 82% to 93%) of reported P values were statistically significant. Use of Bayesian methods was scant (2.5%) and rarely (0.7%) articles relied exclusively on Bayesian statistics. Overall, wider appreciation of the need for multiplicity corrections is a welcome evolution, but the rapid growth of reliance on P values and implausibly high rates of reported statistical significance are worrisome.

Comparison of adaptive statistical iterative and filtered back projection reconstruction techniques in quantifying coronary calcium.

Science.gov (United States)

Takahashi, Masahiro; Kimura, Fumiko; Umezawa, Tatsuya; Watanabe, Yusuke; Ogawa, Harumi

2016-01-01

Adaptive statistical iterative reconstruction (ASIR) has been used to reduce radiation dose in cardiac computed tomography. However, change of image parameters by ASIR as compared to filtered back projection (FBP) may influence quantification of coronary calcium. To investigate the influence of ASIR on calcium quantification in comparison to FBP. In 352 patients, CT images were reconstructed using FBP alone, FBP combined with ASIR 30%, 50%, 70%, and ASIR 100% based on the same raw data. Image noise, plaque density, Agatston scores and calcium volumes were compared among the techniques. Image noise, Agatston score, and calcium volume decreased significantly with ASIR compared to FBP (each P ASIR reduced Agatston score by 10.5% to 31.0%. In calcified plaques both of patients and a phantom, ASIR decreased maximum CT values and calcified plaque size. In comparison to FBP, adaptive statistical iterative reconstruction (ASIR) may significantly decrease Agatston scores and calcium volumes. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Statistical significance approximation in local trend analysis of high-throughput time-series data using the theory of Markov chains.

Science.gov (United States)

Xia, Li C; Ai, Dongmei; Cram, Jacob A; Liang, Xiaoyi; Fuhrman, Jed A; Sun, Fengzhu

2015-09-21

Local trend (i.e. shape) analysis of time series data reveals co-changing patterns in dynamics of biological systems. However, slow permutation procedures to evaluate the statistical significance of local trend scores have limited its applications to high-throughput time series data analysis, e.g., data from the next generation sequencing technology based studies. By extending the theories for the tail probability of the range of sum of Markovian random variables, we propose formulae for approximating the statistical significance of local trend scores. Using simulations and real data, we show that the approximate p-value is close to that obtained using a large number of permutations (starting at time points >20 with no delay and >30 with delay of at most three time steps) in that the non-zero decimals of the p-values obtained by the approximation and the permutations are mostly the same when the approximate p-value is less than 0.05. In addition, the approximate p-value is slightly larger than that based on permutations making hypothesis testing based on the approximate p-value conservative. The approximation enables efficient calculation of p-values for pairwise local trend analysis, making large scale all-versus-all comparisons possible. We also propose a hybrid approach by integrating the approximation and permutations to obtain accurate p-values for significantly associated pairs. We further demonstrate its use with the analysis of the Polymouth Marine Laboratory (PML) microbial community time series from high-throughput sequencing data and found interesting organism co-occurrence dynamic patterns. The software tool is integrated into the eLSA software package that now provides accelerated local trend and similarity analysis pipelines for time series data. The package is freely available from the eLSA website: http://bitbucket.org/charade/elsa.

Test the Overall Significance of p-values by Using Joint Tail Probability of Ordered p-values as Test Statistic

OpenAIRE

Fang, Yongxiang; Wit, Ernst

2008-01-01

Fisher’s combined probability test is the most commonly used method to test the overall significance of a set independent p-values. However, it is very obviously that Fisher’s statistic is more sensitive to smaller p-values than to larger p-value and a small p-value may overrule the other p-values and decide the test result. This is, in some cases, viewed as a flaw. In order to overcome this flaw and improve the power of the test, the joint tail probability of a set p-values is proposed as a ...

Motivational Strategies and Possible Influence on Secondary School ...

African Journals Online (AJOL)

... and administered to the 360 teachers. The data collected were subjected to statistical analyses using ANOVA. The test yielded significant influence of motivational strategies on teachers' work performance. Based on the findings, recommendations were made. KEY WORDS: Motivational Strategies, Teaching Performance.

To what extent does variability of historical rainfall series influence extreme event statistics of sewer system surcharge and overflows?

Science.gov (United States)

Schaarup-Jensen, K; Rasmussen, M R; Thorndahl, S

2009-01-01

In urban drainage modelling long-term extreme statistics has become an important basis for decision-making e.g. in connection with renovation projects. Therefore it is of great importance to minimize the uncertainties with regards to long-term prediction of maximum water levels and combined sewer overflow (CSO) in drainage systems. These uncertainties originate from large uncertainties regarding rainfall inputs, parameters, and assessment of return periods. This paper investigates how the choice of rainfall time series influences the extreme events statistics of max water levels in manholes and CSO volumes. Traditionally, long-term rainfall series, from a local rain gauge, are unavailable. In the present case study, however, long and local rain series are available. 2 rainfall gauges have recorded events for approximately 9 years at 2 locations within the catchment. Beside these 2 gauges another 7 gauges are located at a distance of max 20 kilometers from the catchment. All gauges are included in the Danish national rain gauge system which was launched in 1976. The paper describes to what extent the extreme events statistics based on these 9 series diverge from each other and how this diversity can be handled, e.g. by introducing an "averaging procedure" based on the variability within the set of statistics. All simulations are performed by means of the MOUSE LTS model.

Influence of Immersion Conditions on The Tensile Strength of Recycled Kevlar®/Polyester/Low-Melting-Point Polyester Nonwoven Geotextiles through Applying Statistical Analyses

Directory of Open Access Journals (Sweden)

Jing-Chzi Hsieh

2016-05-01

Full Text Available The recycled Kevlar®/polyester/low-melting-point polyester (recycled Kevlar®/PET/LPET nonwoven geotextiles are immersed in neutral, strong acid, and strong alkali solutions, respectively, at different temperatures for four months. Their tensile strength is then tested according to various immersion periods at various temperatures, in order to determine their durability to chemicals. For the purpose of analyzing the possible factors that influence mechanical properties of geotextiles under diverse environmental conditions, the experimental results and statistical analyses are incorporated in this study. Therefore, influences of the content of recycled Kevlar® fibers, implementation of thermal treatment, and immersion periods on the tensile strength of recycled Kevlar®/PET/LPET nonwoven geotextiles are examined, after which their influential levels are statistically determined by performing multiple regression analyses. According to the results, the tensile strength of nonwoven geotextiles can be enhanced by adding recycled Kevlar® fibers and thermal treatment.

Synchronization from Second Order Network Connectivity Statistics

Science.gov (United States)

Zhao, Liqiong; Beverlin, Bryce; Netoff, Theoden; Nykamp, Duane Q.

2011-01-01

We investigate how network structure can influence the tendency for a neuronal network to synchronize, or its synchronizability, independent of the dynamical model for each neuron. The synchrony analysis takes advantage of the framework of second order networks, which defines four second order connectivity statistics based on the relative frequency of two-connection network motifs. The analysis identifies two of these statistics, convergent connections, and chain connections, as highly influencing the synchrony. Simulations verify that synchrony decreases with the frequency of convergent connections and increases with the frequency of chain connections. These trends persist with simulations of multiple models for the neuron dynamics and for different types of networks. Surprisingly, divergent connections, which determine the fraction of shared inputs, do not strongly influence the synchrony. The critical role of chains, rather than divergent connections, in influencing synchrony can be explained by their increasing the effective coupling strength. The decrease of synchrony with convergent connections is primarily due to the resulting heterogeneity in firing rates. PMID:21779239

Using health statistics: a Nightingale legacy.

Science.gov (United States)

Schloman, B F

2001-01-01

No more forceful example of the value of using health statistics to understand and improve health conditions exists than displayed by Florence Nightingale. The recent book by Dossey (1999), Florence Nightingale: Mystic, Visionary, Healer, relates the dramatic tale of Nightingale s use of statistics to understand the causes of deaths in the Crimean War and of her advocacy to standardize the collection of medical data within the army and in civilian hospitals. For her, the use of health statistics was a major tool to improve health and influence public opinion.

In-group and role identity influences on the initiation and maintenance of students' voluntary attendance at peer study sessions for statistics.

Science.gov (United States)

White, Katherine M; O'Connor, Erin L; Hamilton, Kyra

2011-06-01

Although class attendance is linked to academic performance, questions remain about what determines students' decisions to attend or miss class. In addition to the constructs of a common decision-making model, the theory of planned behaviour, the present study examined the influence of student role identity and university student (in-group) identification for predicting both the initiation and maintenance of students' attendance at voluntary peer-assisted study sessions in a statistics subject. University students enrolled in a statistics subject were invited to complete a questionnaire at two time points across the academic semester. A total of 79 university students completed questionnaires at the first data collection point, with 46 students completing the questionnaire at the second data collection point. Twice during the semester, students' attitudes, subjective norm, perceived behavioural control, student role identity, in-group identification, and intention to attend study sessions were assessed via on-line questionnaires. Objective measures of class attendance records for each half-semester (or 'term') were obtained. Across both terms, students' attitudes predicted their attendance intentions, with intentions predicting class attendance. Earlier in the semester, in addition to perceived behavioural control, both student role identity and in-group identification predicted students' attendance intentions, with only role identity influencing intentions later in the semester. These findings highlight the possible chronology that different identity influences have in determining students' initial and maintained attendance at voluntary sessions designed to facilitate their learning. ©2010 The British Psychological Society.

Statistical analysis of traversal behavior under different types of traffic lights

Science.gov (United States)

Wang, Boran; Wang, Ziyang; Li, Zhiyin

2017-12-01

According to the video observation, it is found that the traffic signal type signal has a significant effect on the illegal crossing behavior of pedestrians at the intersection. Through the method of statistical analysis and variance analysis, the difference between the violation rate and the waiting position of pedestrians at different intersecting lights is compared, and the influence of traffic signal type on pedestrian crossing behavior is evaluated. The results show that the violation rate of the intersection of the static pedestrian lights is significantly higher than that of the countdown signal lights. There are significant differences in the waiting position of the intersection of different signal lights.

Statistical shear lag model - unraveling the size effect in hierarchical composites.

Science.gov (United States)

Wei, Xiaoding; Filleter, Tobin; Espinosa, Horacio D

2015-05-01

Numerous experimental and computational studies have established that the hierarchical structures encountered in natural materials, such as the brick-and-mortar structure observed in sea shells, are essential for achieving defect tolerance. Due to this hierarchy, the mechanical properties of natural materials have a different size dependence compared to that of typical engineered materials. This study aimed to explore size effects on the strength of bio-inspired staggered hierarchical composites and to define the influence of the geometry of constituents in their outstanding defect tolerance capability. A statistical shear lag model is derived by extending the classical shear lag model to account for the statistics of the constituents' strength. A general solution emerges from rigorous mathematical derivations, unifying the various empirical formulations for the fundamental link length used in previous statistical models. The model shows that the staggered arrangement of constituents grants composites a unique size effect on mechanical strength in contrast to homogenous continuous materials. The model is applied to hierarchical yarns consisting of double-walled carbon nanotube bundles to assess its predictive capabilities for novel synthetic materials. Interestingly, the model predicts that yarn gauge length does not significantly influence the yarn strength, in close agreement with experimental observations. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Piloting a Blended Approach to Teaching Statistics in a College of Education: Lessons Learned

Directory of Open Access Journals (Sweden)

Yonghong Jade Xu, Ph.D.

2008-07-01

Full Text Available This study investigated the performance of graduate students enrolled in introductory statistics courses. The course in Fall 2005 was delivered in a traditional face-to-face manner and the same course in Fall 2006 was blended by using an online commercial tutoring system (ALEKS and making attendance of several face-to-face classes optional. There was no significant difference in the t-test comparing performance in the courses, which used the students’ combined score on two mid-terms and the final exam to indicate performance. The ANCOVA analyzing influences on performance in the blended class yielded no significant influence for gender, ethnicity, age, or class type (traditional vs. blended, but a significant influence from students’ incoming GRE-Quantitative score. Seven Likert questions on students’ perception of blended learning were not correlated with student performance. Three focus groups – comprised of low-, medium-, and high-performing students – revealed three themes and several subthemes and differences based on students’ performance level.

After statistics reform : Should we still teach significance testing?

NARCIS (Netherlands)

A. Hak (Tony)

2014-01-01

textabstractIn the longer term null hypothesis significance testing (NHST) will disappear because p- values are not informative and not replicable. Should we continue to teach in the future the procedures of then abolished routines (i.e., NHST)? Three arguments are discussed for not teaching NHST in

Simulating secondary organic aerosol in a regional air quality model using the statistical oxidation model – Part 2: Assessing the influence of vapor wall losses

OpenAIRE

Cappa, Christopher D.; Jathar, Shantanu H.; Kleeman, Michael J.; Docherty, Kenneth S.; Jimenez, Jose L.; Seinfeld, John H.; Wexler, Anthony S.

2016-01-01

The influence of losses of organic vapors to chamber walls during secondary organic aerosol (SOA) formation experiments has recently been established. Here, the influence of such losses on simulated ambient SOA concentrations and properties is assessed in the UCD/CIT regional air quality model using the statistical oxidation model (SOM) for SOA. The SOM was fit to laboratory chamber data both with and without accounting for vapor wall losses following the approa...

Worry, Intolerance of Uncertainty, and Statistics Anxiety

Science.gov (United States)

Williams, Amanda S.

2013-01-01

Statistics anxiety is a problem for most graduate students. This study investigates the relationship between intolerance of uncertainty, worry, and statistics anxiety. Intolerance of uncertainty was significantly related to worry, and worry was significantly related to three types of statistics anxiety. Six types of statistics anxiety were…

Reducing statistics anxiety and enhancing statistics learning achievement: effectiveness of a one-minute strategy.

Science.gov (United States)

Chiou, Chei-Chang; Wang, Yu-Min; Lee, Li-Tze

2014-08-01

Statistical knowledge is widely used in academia; however, statistics teachers struggle with the issue of how to reduce students' statistics anxiety and enhance students' statistics learning. This study assesses the effectiveness of a "one-minute paper strategy" in reducing students' statistics-related anxiety and in improving students' statistics-related achievement. Participants were 77 undergraduates from two classes enrolled in applied statistics courses. An experiment was implemented according to a pretest/posttest comparison group design. The quasi-experimental design showed that the one-minute paper strategy significantly reduced students' statistics anxiety and improved students' statistics learning achievement. The strategy was a better instructional tool than the textbook exercise for reducing students' statistics anxiety and improving students' statistics achievement.

Testing earthquake prediction algorithms: Statistically significant advance prediction of the largest earthquakes in the Circum-Pacific, 1992-1997

Science.gov (United States)

Kossobokov, V.G.; Romashkova, L.L.; Keilis-Borok, V. I.; Healy, J.H.

1999-01-01

Algorithms M8 and MSc (i.e., the Mendocino Scenario) were used in a real-time intermediate-term research prediction of the strongest earthquakes in the Circum-Pacific seismic belt. Predictions are made by M8 first. Then, the areas of alarm are reduced by MSc at the cost that some earthquakes are missed in the second approximation of prediction. In 1992-1997, five earthquakes of magnitude 8 and above occurred in the test area: all of them were predicted by M8 and MSc identified correctly the locations of four of them. The space-time volume of the alarms is 36% and 18%, correspondingly, when estimated with a normalized product measure of empirical distribution of epicenters and uniform time. The statistical significance of the achieved results is beyond 99% both for M8 and MSc. For magnitude 7.5 + , 10 out of 19 earthquakes were predicted by M8 in 40% and five were predicted by M8-MSc in 13% of the total volume considered. This implies a significance level of 81% for M8 and 92% for M8-MSc. The lower significance levels might result from a global change in seismic regime in 1993-1996, when the rate of the largest events has doubled and all of them become exclusively normal or reversed faults. The predictions are fully reproducible; the algorithms M8 and MSc in complete formal definitions were published before we started our experiment [Keilis-Borok, V.I., Kossobokov, V.G., 1990. Premonitory activation of seismic flow: Algorithm M8, Phys. Earth and Planet. Inter. 61, 73-83; Kossobokov, V.G., Keilis-Borok, V.I., Smith, S.W., 1990. Localization of intermediate-term earthquake prediction, J. Geophys. Res., 95, 19763-19772; Healy, J.H., Kossobokov, V.G., Dewey, J.W., 1992. A test to evaluate the earthquake prediction algorithm, M8. U.S. Geol. Surv. OFR 92-401]. M8 is available from the IASPEI Software Library [Healy, J.H., Keilis-Borok, V.I., Lee, W.H.K. (Eds.), 1997. Algorithms for Earthquake Statistics and Prediction, Vol. 6. IASPEI Software Library]. ?? 1999 Elsevier

Safety culture : a significant influence on safety in transportation

Science.gov (United States)

2017-08-01

An organizations safety culture can influence safety outcomes. Research and experience show that when safety culture is strong, accidents are less frequent and less severe. As a result, building and maintaining strong safety cultures should be a t...

A novel complete-case analysis to determine statistical significance between treatments in an intention-to-treat population of randomized clinical trials involving missing data.

Science.gov (United States)

Liu, Wei; Ding, Jinhui

2018-04-01

The application of the principle of the intention-to-treat (ITT) to the analysis of clinical trials is challenged in the presence of missing outcome data. The consequences of stopping an assigned treatment in a withdrawn subject are unknown. It is difficult to make a single assumption about missing mechanisms for all clinical trials because there are complicated reactions in the human body to drugs due to the presence of complex biological networks, leading to data missing randomly or non-randomly. Currently there is no statistical method that can tell whether a difference between two treatments in the ITT population of a randomized clinical trial with missing data is significant at a pre-specified level. Making no assumptions about the missing mechanisms, we propose a generalized complete-case (GCC) analysis based on the data of completers. An evaluation of the impact of missing data on the ITT analysis reveals that a statistically significant GCC result implies a significant treatment effect in the ITT population at a pre-specified significance level unless, relative to the comparator, the test drug is poisonous to the non-completers as documented in their medical records. Applications of the GCC analysis are illustrated using literature data, and its properties and limits are discussed.

Organizational downsizing and age discrimination litigation: the influence of personnel practices and statistical evidence on litigation outcomes.

Science.gov (United States)

Wingate, Peter H; Thornton, George C; McIntyre, Kelly S; Frame, Jennifer H

2003-02-01

The present study examined relationships between reduction-in-force (RIF) personnel practices, presentation of statistical evidence, and litigation outcomes. Policy capturing methods were utilized to analyze the components of 115 federal district court opinions involving age discrimination disparate treatment allegations and organizational downsizing. Univariate analyses revealed meaningful links between RIF personnel practices, use of statistical evidence, and judicial verdict. The defendant organization was awarded summary judgment in 73% of the claims included in the study. Judicial decisions in favor of the defendant organization were found to be significantly related to such variables as formal performance appraisal systems, termination decision review within the organization, methods of employee assessment and selection for termination, and the presence of a concrete layoff policy. The use of statistical evidence in ADEA disparate treatment litigation was investigated and found to be a potentially persuasive type of indirect evidence. Legal, personnel, and evidentiary ramifications are reviewed, and a framework of downsizing mechanics emphasizing legal defensibility is presented.

Influence of pilates training on the quality of life of chronic stroke patients.

Science.gov (United States)

Yun, Seok-Min; Park, Sang-Kyoon; Lim, Hee Sung

2017-10-01

[Purpose] This study was to observe the influence of Pilates training on the quality of life in chronic stoke patients. [Subjects and Methods] Forty chronic stroke patients participated in this study. They were divided into same number of experimental group (EG) and control group (CG). EG participated in a 60-min Pilates training program, twice a week for 12 weeks, while the CG did not participate in any exercise-related activities for the duration and participating in general occupational therapy without any exercise-related activities. Then the MMSE-K was performed before and after Pilates training to observe the influence of Pilates training on the quality of life in chronic stroke patients. [Results] Statistically significant improvement in the physical, social, and psychological domains was found in EG after the training. No statistically significant difference was found in all three quality of life domains for the CG. EG experienced a statistically significant improvement in all quality of life domains compared with that of CG. [Conclusion] Therefore, participation in Pilates training was found to effectively improve the quality of life in stroke patients. Pilates training involves low and intermediate intensity resistance and repetition that match the patient's physical ability and can be a remedial exercise program that can improve physical ability and influence quality of life.

Experimental investigation of statistical models describing distribution of counts

International Nuclear Information System (INIS)

Salma, I.; Zemplen-Papp, E.

1992-01-01

The binomial, Poisson and modified Poisson models which are used for describing the statistical nature of the distribution of counts are compared theoretically, and conclusions for application are considered. The validity of the Poisson and the modified Poisson statistical distribution for observing k events in a short time interval is investigated experimentally for various measuring times. The experiments to measure the influence of the significant radioactive decay were performed with 89 Y m (T 1/2 =16.06 s), using a multichannel analyser (4096 channels) in the multiscaling mode. According to the results, Poisson statistics describe the counting experiment for short measuring times (up to T=0.5T 1/2 ) and its application is recommended. However, analysis of the data demonstrated, with confidence, that for long measurements (T≥T 1/2 ) Poisson distribution is not valid and the modified Poisson function is preferable. The practical implications in calculating uncertainties and in optimizing the measuring time are discussed. Differences between the standard deviations evaluated on the basis of the Poisson and binomial models are especially significant for experiments with long measuring time (T/T 1/2 ≥2) and/or large detection efficiency (ε>0.30). Optimization of the measuring time for paired observations yields the same solution for either the binomial or the Poisson distribution. (orig.)

[Clinical Significance of HBV Detection in NHL Patients].

Science.gov (United States)

Zhang, Tian-Ling; Zhang, Juan; Lv, Cheng-Xiu; Hu, Tian-Yu; Li, Qing

2018-04-01

To analyze the relation of HBV infection with clinical characteristics and prognosis in NHL patients, so as to explore the significance of HBV detection. Sixty-eight NHL patients from December 2013 to December 2016 were enrolled in NHL group and 136 patients with other malignancies were chosen in control group, the detectable rate of HBV was compared between 2 groups. The correlation of HBV infection with sex, age, stage, cell origin, expression of P53 and BCL-2 in NHL patients was analyzed. The prognosis-related factors in NHL patients were also analyzed. The infection rate of HBV in NHL group was 51.47%(35/68), that in control group was 15.44% (21/136), and the difference was statistically significant(χ 2 =27.768,PHBV infection correlated with cell origins and expression of BCL-2 in NHL patients(PHBV infection (P>0.05), while the prognosis was significantly related with stage, expression of P53 and BCL-2(PHBV infection correlates with BCL-2 expression level of NHL patients, and shows influence on the prognosis of patients.

ZnO crystals obtained by electrodeposition: Statistical analysis of most important process variables

International Nuclear Information System (INIS)

Cembrero, Jesus; Busquets-Mataix, David

2009-01-01

In this paper a comparative study by means of a statistical analysis of the main process variables affecting ZnO crystal electrodeposition is presented. ZnO crystals were deposited on two different substrates, silicon wafer and indium tin oxide. The control variables were substrate types, electrolyte concentration, temperature, exposition time and current density. The morphologies of the different substrates were observed using scanning electron microscopy. The percentage of substrate area covered by ZnO deposit was calculated by computational image analysis. The design of the applied experiments was based on a two-level factorial analysis involving a series of 32 experiments and an analysis of variance. Statistical results reveal that variables exerting a significant influence on the area covered by ZnO deposit are electrolyte concentration, substrate type and time of deposition, together with a combined two-factor interaction between temperature and current density. However, morphology is also influenced by surface roughness of the substrates

Applied statistical thermodynamics

CERN Document Server

Lucas, Klaus

1991-01-01

The book guides the reader from the foundations of statisti- cal thermodynamics including the theory of intermolecular forces to modern computer-aided applications in chemical en- gineering and physical chemistry. The approach is new. The foundations of quantum and statistical mechanics are presen- ted in a simple way and their applications to the prediction of fluid phase behavior of real systems are demonstrated. A particular effort is made to introduce the reader to expli- cit formulations of intermolecular interaction models and to show how these models influence the properties of fluid sy- stems. The established methods of statistical mechanics - computer simulation, perturbation theory, and numerical in- tegration - are discussed in a style appropriate for newcom- ers and are extensively applied. Numerous worked examples illustrate how practical calculations should be carried out.

The influence of 'significant others' on persistent back pain and work participation: A qualitative exploration of illness perceptions

Directory of Open Access Journals (Sweden)

King Nigel

2011-10-01

Full Text Available Abstract Background Individual illness perceptions have been highlighted as important influences on clinical outcomes for back pain. However, the illness perceptions of 'significant others' (spouse/partner/close family member are rarely explored, particularly in relation to persistent back pain and work participation. The aim of this study was to initiate qualitative research in this area in order to further understand these wider influences on outcome. Methods Semi-structured interviews based on the chronic pain version of the Illness Perceptions Questionnaire-Revised were conducted with a convenience sample of UK disability benefit claimants, along with their significant others (n = 5 dyads. Data were analysed using template analysis. Results Significant others shared, and perhaps further reinforced, claimants' unhelpful illness beliefs including fear of pain/re-injury associated with certain types of work and activity, and pessimism about the likelihood of return to work. In some cases, significant others appeared more resigned to the permanence and negative inevitable consequences of the claimant's back pain condition on work participation, and were more sceptical about the availability of suitable work and sympathy from employers. In their pursuit of authenticity, claimants were keen to stress their desire to work whilst emphasising how the severity and physical limitations of their condition prevented them from doing so. In this vein, and seemingly based on their perceptions of what makes a 'good' significant other, significant others acted as a 'witness to pain', supporting claimants' self-limiting behaviour and statements of incapacity, often responding with empathy and assistance. The beliefs and responses of significant others may also have been influenced by their own experience of chronic illness, thus participants lives were often intertwined and defined by illness. Conclusions The findings from this exploratory study reveal how

Safety culture and networks of influence

International Nuclear Information System (INIS)

Pereira, Carlos Henrique V.; Barroso, Antonio C.O.; Vieira Neto, Antonio S.

2011-01-01

This paper analyzes the social networks that influence the formation and maintenance of the safety culture within the Institute of Energy and Nuclear Research (IPEN-CNEN/SP). From the mapping and analysis of social networks, actors with a significant degree of influence were identified. Later using a questionnaire, the beliefs of the population sample were mapped. Thus, the importance of key actors in the network analysis could be confirmed statistically. Therefore, based on the mentioned methods we could demonstrate our hypothesis, that there are some social networks that are important in the formation of safety culture, as well as the fact that the influence of some distinguished actors plays an essential role in this amalgam. (author)

Safety culture and networks of influence

Energy Technology Data Exchange (ETDEWEB)

Pereira, Carlos Henrique V.; Barroso, Antonio C.O.; Vieira Neto, Antonio S., E-mail: carloshvp@usp.br, E-mail: barroso@ipen.br, E-mail: asvneto@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

This paper analyzes the social networks that influence the formation and maintenance of the safety culture within the Institute of Energy and Nuclear Research (IPEN-CNEN/SP). From the mapping and analysis of social networks, actors with a significant degree of influence were identified. Later using a questionnaire, the beliefs of the population sample were mapped. Thus, the importance of key actors in the network analysis could be confirmed statistically. Therefore, based on the mentioned methods we could demonstrate our hypothesis, that there are some social networks that are important in the formation of safety culture, as well as the fact that the influence of some distinguished actors plays an essential role in this amalgam. (author)

[Influence of postoperative pelvic floor function on different surgical procedures of hysterectomy].

Science.gov (United States)

Tan, A L; Hong, L; Zhao, Y Z; Jiang, L

2017-05-25

Objective: To compare the influence of postoperative pelvic floor function after different surgical procedures of hysterectomy. Methods: A total of 260 patients who underwent hysterectomy in Renmin hospital of Wuhan University from January 2012 to January 2014 were enrolled in the study, and divided into 5 groups by different surgical procedures, which were total abdominal hysterectomy (A-TH; 46 cases), total laparoscopic hysterectomy (L-TH; 59 cases), total vaginal hysterectomy (V-TH; 42 cases), abdominal intrafascial hysterectomy (A-CISH; 78 cases), laparoscopic intrafascial hysterectomy (L-CISH; 35 cases). Pelvic examination, pelvic organ prolapse quantitation (POP-Q), test of pelvic muscle strength, pelvic floor distress inventory-short form 20 (PFDI-20) and the female sexual function index (FSFI) questionnaire were measured after 6 months and 12 months. Results: The differences of pelvic organ prolapse incidence after 6 months, A-TH and A-CISH [7% (3/46) versus 3% (2/78)], A-TH and L-CISH [7% (3/46) versus 3% (1/35)] were statistically significance (all P CISH was statistically different in degree ( P CISH [59% (27/46) versus 29% (23/78)], A-TH and L-CISH [59% (27/46) versus 26% (9/35)] were statistically significant (all P CISH [61% (36/59) versus 29%(23/78)] was statistically different ( P CISH [53% (31/59) verus 24% (19/78)], V-TH and A-CISH [60% (25/42) verus 24% (19/78)], V-TH and L-CISH [60% (25/42) verus 23% (8/35)] were statistically significant (all P CISH [57% (24/42) versus 26%(20/78)] was statistically significant ( P 0.05), PFDI-20 total score was not statistically significant ( P >0.05). FSFI total score after 6 months and 12 months in A-TH and A-CISH, L-TH and A-CISH, A-CISH and L-CISH were statistically significant (all P <0.05). Conclusion: The influences of different surgical procedures to pelvic floor function are no statistical difference; as to the surgical resection of hysterectomy, intrafascia hysterectomy compared with extrafascia

An Exploration of Student Attitudes and Satisfaction in a GAISE-Influenced Introductory Statistics Course

Science.gov (United States)

Paul, Warren; Cunnington, R. Clare

2017-01-01

We used the Survey of Attitudes Toward Statistics to (1) evaluate using presemester data the Students' Attitudes Toward Statistics Model (SATS-M), and (2) test the effect on attitudes of an introductory statistics course redesigned according to the Guidelines for Assessment and Instruction in Statistics Education (GAISE) by examining the change in…

The issue of statistical power for overall model fit in evaluating structural equation models

Directory of Open Access Journals (Sweden)

Richard HERMIDA

2015-06-01

Full Text Available Statistical power is an important concept for psychological research. However, examining the power of a structural equation model (SEM is rare in practice. This article provides an accessible review of the concept of statistical power for the Root Mean Square Error of Approximation (RMSEA index of overall model fit in structural equation modeling. By way of example, we examine the current state of power in the literature by reviewing studies in top Industrial-Organizational (I/O Psychology journals using SEMs. Results indicate that in many studies, power is very low, which implies acceptance of invalid models. Additionally, we examined methodological situations which may have an influence on statistical power of SEMs. Results showed that power varies significantly as a function of model type and whether or not the model is the main model for the study. Finally, results indicated that power is significantly related to model fit statistics used in evaluating SEMs. The results from this quantitative review imply that researchers should be more vigilant with respect to power in structural equation modeling. We therefore conclude by offering methodological best practices to increase confidence in the interpretation of structural equation modeling results with respect to statistical power issues.

Does Degree of Work Task Completion Influence Retrieval Performance?

DEFF Research Database (Denmark)

Ingwersen, Peter; Bogers, Toine; Lykke, Marianne

2010-01-01

their perception of task completion. Also, with the exception of full text records and across all document types, both measured at rank 10, no statistically significant correlation is observed with respect to retrieval performance influenced by degrees of perceived work task completion or individual types......In this contribution we investigate the potential influence between assessors’ perceived completion of their work task at hand and their actual assessment of usefulness of the retrieved information. The results indicate that the number of useful documents found by assessors does not influence...

Statistical frequency in perception affects children's lexical production.

Science.gov (United States)

Richtsmeier, Peter T; Gerken, LouAnn; Goffman, Lisa; Hogan, Tiffany

2009-06-01

Children's early word production is influenced by the statistical frequency of speech sounds and combinations. Three experiments asked whether this production effect can be explained by a perceptual learning mechanism that is sensitive to word-token frequency and/or variability. Four-year-olds were exposed to nonwords that were either frequent (presented 10 times) or infrequent (presented once). When the frequent nonwords were spoken by the same talker, children showed no significant effect of perceptual frequency on production. When the frequent nonwords were spoken by different talkers, children produced them with fewer errors and shorter latencies. The results implicate token variability in perceptual learning.

Statistical modelling of citation exchange between statistics journals.

Science.gov (United States)

Varin, Cristiano; Cattelan, Manuela; Firth, David

2016-01-01

Rankings of scholarly journals based on citation data are often met with scepticism by the scientific community. Part of the scepticism is due to disparity between the common perception of journals' prestige and their ranking based on citation counts. A more serious concern is the inappropriate use of journal rankings to evaluate the scientific influence of researchers. The paper focuses on analysis of the table of cross-citations among a selection of statistics journals. Data are collected from the Web of Science database published by Thomson Reuters. Our results suggest that modelling the exchange of citations between journals is useful to highlight the most prestigious journals, but also that journal citation data are characterized by considerable heterogeneity, which needs to be properly summarized. Inferential conclusions require care to avoid potential overinterpretation of insignificant differences between journal ratings. Comparison with published ratings of institutions from the UK's research assessment exercise shows strong correlation at aggregate level between assessed research quality and journal citation 'export scores' within the discipline of statistics.

THE IMPACT OF THE UNEMPLOYMENT RATE ON THE INSURANCE DEVELOPMENT IN ROMANIA. STATISTICAL APPROACHES

Directory of Open Access Journals (Sweden)

CRISTEA MIRELA

2016-12-01

Full Text Available A significant component of a developed economy, insurance holds a prominent role in European countries, its own contribution being noticed in the GDP of every country. The involvements of unemployment on the insurance market size have been reviewed in numerous specialized papers internationally. Based on these results, but also on the fact that in Romania there have not been measured such statistical correlations showing to what extent the unemployment rate influences the main indicators in the insurance field, in this research we analyze the statistical correlation between results which reveal the dimension of the insurance market - the penetration degree and the insurance density - and the unemployment rate. To perform the analysis, we apply statistical methods, for the period 1997-2015. The results are analysed in the context of the relevant international statistics, as well as reported to the Romanian general economic framework.

Influence of age on community health worker's knowledge and ...

African Journals Online (AJOL)

Influence of age on community health worker's knowledge and service provision for maternal, newborn, and child health in Morogoro region, Tanzania. ... However there was a statistically significant difference (p<0.05) in marital status, education levels, use of English language, number of dependants, and income from ...

Factors Influencing Stress, Burnout, and Retention of Secondary Teachers

Science.gov (United States)

Fisher, Molly H.

2011-01-01

This study examines the stress, burnout, satisfaction, and preventive coping skills of nearly 400 secondary teachers to determine variables contributing to these major factors influencing teachers. Analysis of Variance (ANOVA) statistics were conducted that found the burnout levels between new and experienced teachers are significantly different,…

Statistics anxiety, state anxiety during an examination, and academic achievement.

Science.gov (United States)

Macher, Daniel; Paechter, Manuela; Papousek, Ilona; Ruggeri, Kai; Freudenthaler, H Harald; Arendasy, Martin

2013-12-01

A large proportion of students identify statistics courses as the most anxiety-inducing courses in their curriculum. Many students feel impaired by feelings of state anxiety in the examination and therefore probably show lower achievements. The study investigates how statistics anxiety, attitudes (e.g., interest, mathematical self-concept) and trait anxiety, as a general disposition to anxiety, influence experiences of anxiety as well as achievement in an examination. Participants were 284 undergraduate psychology students, 225 females and 59 males. Two weeks prior to the examination, participants completed a demographic questionnaire and measures of the STARS, the STAI, self-concept in mathematics, and interest in statistics. At the beginning of the statistics examination, students assessed their present state anxiety by the KUSTA scale. After 25 min, all examination participants gave another assessment of their anxiety at that moment. Students' examination scores were recorded. Structural equation modelling techniques were used to test relationships between the variables in a multivariate context. Statistics anxiety was the only variable related to state anxiety in the examination. Via state anxiety experienced before and during the examination, statistics anxiety had a negative influence on achievement. However, statistics anxiety also had a direct positive influence on achievement. This result may be explained by students' motivational goals in the specific educational setting. The results provide insight into the relationship between students' attitudes, dispositions, experiences of anxiety in the examination, and academic achievement, and give recommendations to instructors on how to support students prior to and in the examination. © 2012 The British Psychological Society.

Evaluating statistical and clinical significance of intervention effects in single-case experimental designs: an SPSS method to analyze univariate data.

Science.gov (United States)

Maric, Marija; de Haan, Else; Hogendoorn, Sanne M; Wolters, Lidewij H; Huizenga, Hilde M

2015-03-01

Single-case experimental designs are useful methods in clinical research practice to investigate individual client progress. Their proliferation might have been hampered by methodological challenges such as the difficulty applying existing statistical procedures. In this article, we describe a data-analytic method to analyze univariate (i.e., one symptom) single-case data using the common package SPSS. This method can help the clinical researcher to investigate whether an intervention works as compared with a baseline period or another intervention type, and to determine whether symptom improvement is clinically significant. First, we describe the statistical method in a conceptual way and show how it can be implemented in SPSS. Simulation studies were performed to determine the number of observation points required per intervention phase. Second, to illustrate this method and its implications, we present a case study of an adolescent with anxiety disorders treated with cognitive-behavioral therapy techniques in an outpatient psychotherapy clinic, whose symptoms were regularly assessed before each session. We provide a description of the data analyses and results of this case study. Finally, we discuss the advantages and shortcomings of the proposed method. Copyright © 2014. Published by Elsevier Ltd.

Performance studies of GooFit on GPUs vs RooFit on CPUs while estimating the statistical significance of a new physical signal

Science.gov (United States)

Di Florio, Adriano

2017-10-01

In order to test the computing capabilities of GPUs with respect to traditional CPU cores a high-statistics toy Monte Carlo technique has been implemented both in ROOT/RooFit and GooFit frameworks with the purpose to estimate the statistical significance of the structure observed by CMS close to the kinematical boundary of the J/ψϕ invariant mass in the three-body decay B + → J/ψϕK +. GooFit is a data analysis open tool under development that interfaces ROOT/RooFit to CUDA platform on nVidia GPU. The optimized GooFit application running on GPUs hosted by servers in the Bari Tier2 provides striking speed-up performances with respect to the RooFit application parallelised on multiple CPUs by means of PROOF-Lite tool. The considerable resulting speed-up, evident when comparing concurrent GooFit processes allowed by CUDA Multi Process Service and a RooFit/PROOF-Lite process with multiple CPU workers, is presented and discussed in detail. By means of GooFit it has also been possible to explore the behaviour of a likelihood ratio test statistic in different situations in which the Wilks Theorem may or may not apply because its regularity conditions are not satisfied.

Influence of the Budgetary Decentralization on the Economic Growth of Regions of Ukraine: Statistical Estimation

Directory of Open Access Journals (Sweden)

Voznyak Halyna V.

2017-06-01

Full Text Available The aim of the article is to define, determine and analyze the interrelationships between the budgetary decentralization and the economic growth of regions of Ukraine under conditions of reforming the power and financial resources. A statistical estimation of the influence of the budgetary decentralization on the economic growth of regions of Ukraine for 2015-2016 is carried out. The application of the panel data modeling allowed to build econometric models that made it possible to determine the ambiguous nature of the budgetary decentralization and identify key factors of its influence. It is shown that in terms of the income and expenditures the budgetary decentralization is positively associated with the economic growth of regions of Ukraine during the chosen time range of the study. The dynamic growth of the own revenues of local budgets is not a catalyst for the economic development of the regions. A strong negative effect of transfers on the dependent variable is confirmed. Among the variables included in the model and additionally characterizing the budgetary decentralization, the single tax and subsidies for the socio-economic development of individual territories attract attention. As a result of the study, the author justifies the need to minimize the transfer dependence of the regions at a simultaneous increasing of their own revenue base with local taxes and fees serving as a reliable basis for a long-term planning and development.

Serum Copper Level Significantly Influences Platelet Count, Lymphocyte Count and Mean Cell Hemoglobin in Sickle Cell Anemia

Directory of Open Access Journals (Sweden)

Okocha Chide

2015-12-01

Full Text Available Background Changes in serum micro nutrients levels affect a number of critically important metabolic processes; these could potentially influence blood counts and ultimately disease presentation in patients with sickle cell anemia (SCA. Objectives To evaluate the influence of serum micro-nutrients levels; zinc, copper, selenium and magnesium on blood counts in steady state SCA patients. Methods A cross sectional study that involved 28 steady state adult SCA subjects. Seven milliliters (mls of blood was collected; 3 mls was for hemoglobin electrophoresis and full blood count determination while 4 mls was for measurement of serum micro nutrients levels, by the atomic absorption spectrophotometry. Correlation between serum micro-nutrient levels and blood counts was done by the Pearson’s linear regression. Ethical approval was obtained from the institutional review board and each participant gave informed consent. All data was analyzed by SPSS software version 20. Results There was a significant correlation between serum copper levels and mean cell hemoglobin (MCH, platelet and lymphocyte counts (r = 0.418; P = 0.02, r = -0.376; P = 0.04 and r = -0.383; P = 0.04, respectively. There were no significant correlations between serum levels of other micro nutrients (selenium, zinc and magnesium and blood counts. Conclusions Copper influences blood count in SCA patients probably by inducing red cell haemolysis, oxidant tissue damage and stimulating the immune system.

Statistical estimation of fast-reactor fuel-element lifetime

International Nuclear Information System (INIS)

Proshkin, A.A.; Likhachev, Yu.I.; Tuzov, A.N.; Zabud'ko, L.M.

1980-01-01

On the basis of a statistical analysis, the main parameters having a significant influence on the theoretical determination of fuel-element lifetimes in the operation of power fast reactors in steady power conditions are isolated. These include the creep and swelling of the fuel and shell materials, prolonged-plasticity lag, shell-material corrosion, gap contact conductivity, and the strain diagrams of the shell and fuel materials obtained for irradiated materials at the corresponding strain rates. By means of deeper investigation of these properties of the materials, it is possible to increase significantly the reliability of fuel-element lifetime predictions in designing fast reactors and to optimize the structure of fuel elements more correctly. The results of such calculations must obviously be taken into account in the cost-benefit analysis of projected new reactors and in choosing the optimal fuel burnup. 9 refs

Robust statistical methods for significance evaluation and applications in cancer driver detection and biomarker discovery

DEFF Research Database (Denmark)

Madsen, Tobias

2017-01-01

In the present thesis I develop, implement and apply statistical methods for detecting genomic elements implicated in cancer development and progression. This is done in two separate bodies of work. The first uses the somatic mutation burden to distinguish cancer driver mutations from passenger m...

Facts and Findings on the Statistical Discrepancies of the Korean Balance of Payments

Directory of Open Access Journals (Sweden)

Sangyong Joo

2000-03-01

Full Text Available The Korea experienced drastic increases in the statistical discrepancy in balance of payments since 1997. In general, the expansion and complexity of external transactions induced by contributing capital account liberalization has contributed to this fact. The abolition of the export/import approval system seems to have accelerated the mismeasurement and omissions in external transactions. Of course, the influence of currency crisis occurred cannot be ruled out. Among economic factors, Won/dollar exchange rate volatility is found to have significant explanatory power on the magnitude of statistical discrepancy, while exchange rate returns have not. WE interpret this as the demand for relatively safe currency rising in presence of the uncertainty in domestic currency values.

A robust statistical method for association-based eQTL analysis.

Directory of Open Access Journals (Sweden)

Ning Jiang

Full Text Available It has been well established that theoretical kernel for recently surging genome-wide association study (GWAS is statistical inference of linkage disequilibrium (LD between a tested genetic marker and a putative locus affecting a disease trait. However, LD analysis is vulnerable to several confounding factors of which population stratification is the most prominent. Whilst many methods have been proposed to correct for the influence either through predicting the structure parameters or correcting inflation in the test statistic due to the stratification, these may not be feasible or may impose further statistical problems in practical implementation.We propose here a novel statistical method to control spurious LD in GWAS from population structure by incorporating a control marker into testing for significance of genetic association of a polymorphic marker with phenotypic variation of a complex trait. The method avoids the need of structure prediction which may be infeasible or inadequate in practice and accounts properly for a varying effect of population stratification on different regions of the genome under study. Utility and statistical properties of the new method were tested through an intensive computer simulation study and an association-based genome-wide mapping of expression quantitative trait loci in genetically divergent human populations.The analyses show that the new method confers an improved statistical power for detecting genuine genetic association in subpopulations and an effective control of spurious associations stemmed from population structure when compared with other two popularly implemented methods in the literature of GWAS.

Significant Factors Influencing Rural Residents’ Well-Being with Regard to Electricity Consumption: An Empirical Analysis in China

Directory of Open Access Journals (Sweden)

Sen Guo

2016-11-01

Full Text Available The electric universal service policy, which has been implemented for many years in China, aims to meet the basic electricity demands of rural residents. Electricity consumption can facilitate the daily life of rural residents, such as lighting and cooking, which are necessary to their well-being. In practice, the well-being of rural residents due to electricity consumption is influenced by many factors. Therefore, to improve the well-being of rural residents, it is quite necessary to identify and optimize the significant factors that make the electric universal service policy play its prescribed role as well as possible. In this paper, the significant factors influencing rural residents’ well-being obtained from electricity consumption were identified and discussed by employing the Ordered Probit model. The results indicate that: (1 there are six significant factors, of which ‘educational level’, ‘health condition’, ‘each person income of a family per month’, and ‘service time of household appliances’ play positive roles in rural residents’ well-being, while ‘average power interruption times’ and ‘monthly electric charges’ have negative impacts; (2 for significant factors with positive roles, ‘educational level’ and ‘health condition’ show larger marginal effects on rural residents’ well-being; and (3 for significant factors with negative impacts, ‘average power interruption times’ has the greatest marginal effect. Finally, policy implications are proposed for improving rural residents’ well-being, which can also contribute to the effective implementation of the electric universal service policy in China.

Significance evaluation in factor graphs

DEFF Research Database (Denmark)

Madsen, Tobias; Hobolth, Asger; Jensen, Jens Ledet

2017-01-01

in genomics and the multiple-testing issues accompanying them, accurate significance evaluation is of great importance. We here address the problem of evaluating statistical significance of observations from factor graph models. Results Two novel numerical approximations for evaluation of statistical...... significance are presented. First a method using importance sampling. Second a saddlepoint approximation based method. We develop algorithms to efficiently compute the approximations and compare them to naive sampling and the normal approximation. The individual merits of the methods are analysed both from....... Conclusions The applicability of saddlepoint approximation and importance sampling is demonstrated on known models in the factor graph framework. Using the two methods we can substantially improve computational cost without compromising accuracy. This contribution allows analyses of large datasets...

In situ influence of coal ash dump on the quality of neighboring surface and ground waters by applying correlation statistic analysis

Energy Technology Data Exchange (ETDEWEB)

Jasna M. Djinovic; Aleksandar R. Popovic [University of Belgrade, Belgrade (Serbia and Montenegro). Center of Chemistry, Institute of Chemistry, Technology and Metallurgy

2007-01-15

The aim of this study was to establish the real in situ influence of coal ash and slag transport and storage on the quality of neighboring surface and ground waters by applying correlation statistic analysis. It was found that the waste waters from the coal ash dump do not have any influence on the quality of the Danube river water. The Danube and the waste waters, however, influence the quality of the ground waters of the Petka spring. Changes in the concentrations of elements in the Danube or in the waste waters can have immediate or delayed impact on the quality of the spring waters. The immediate impact has calcium, magnesium, zinc, copper, vanadium, cobalt from Danube; magnesium, vanadium from overflow and drainage waters; copper from drainage water. And the delayed impact has calcium, magnesium, vanadium and silicon from the Danube waters, cobalt from drainage waters, chromium and silicon from overflow waters and magnesium and vanadium from both overflow and drainage waters. 20 refs., 2 figs., 4 tabs.

Robust statistical methods with R

CERN Document Server

Jureckova, Jana

2005-01-01

Robust statistical methods were developed to supplement the classical procedures when the data violate classical assumptions. They are ideally suited to applied research across a broad spectrum of study, yet most books on the subject are narrowly focused, overly theoretical, or simply outdated. Robust Statistical Methods with R provides a systematic treatment of robust procedures with an emphasis on practical application.The authors work from underlying mathematical tools to implementation, paying special attention to the computational aspects. They cover the whole range of robust methods, including differentiable statistical functions, distance of measures, influence functions, and asymptotic distributions, in a rigorous yet approachable manner. Highlighting hands-on problem solving, many examples and computational algorithms using the R software supplement the discussion. The book examines the characteristics of robustness, estimators of real parameter, large sample properties, and goodness-of-fit tests. It...

The region of influence of significant defects and the mechanical vibrations of linear elastic solids

International Nuclear Information System (INIS)

Suarez Antola, R.

2004-12-01

The presence of cracks, voids or fields of pores, and their growth under applied forces or environmental actions, can produce a meaningful lowering in the proper frequencies of normal modes of mechanical vibration in machines and structures. A quite general expression for the square of modes proper frequency as a functional of displacement field, density field and elastic moduli fields is used as a starting point. The effect of defects on frequency are modeled as equivalent changes in density and elastic moduli fields, introducing the concept of region of influence of each defect. This region of influence is derived from the relation between the stress field of flawed components in machines or structures, and the elastic energy released from a suitable reference state, due to the presence of significant defects in the above mentioned mechanical components. An approximate analytical expression is obtained, which relates the relative variation in the square of mode s proper frequency with position, size, shape and orientation of defects in mode displacement field. Some simple mathematical models of machine and structural elements with cracks or fields of pores are considered as examples. The connections between the relative lowering in the square of mode s proper frequency and the stress intensity factor of a defect are discussed : the concept of region of influence of a defect is used as a bridge between (low frequency and low amplitude) vibration dynamics and linear elastic fracture mechanics. Some limitations of the present approach are discussed as well as the possibility of applying the region of influence of defects to the damping of normal modes of vibration

Statistical Power in Longitudinal Network Studies

NARCIS (Netherlands)

Stadtfeld, Christoph; Snijders, Tom A. B.; Steglich, Christian; van Duijn, Marijtje

2018-01-01

Longitudinal social network studies may easily suffer from a lack of statistical power. This is the case in particular for studies that simultaneously investigate change of network ties and change of nodal attributes. Such selection and influence studies have become increasingly popular due to the

Prognostic significance of obstructive uropathy in advanced prostate cancer.

Science.gov (United States)

Oefelein, Michael G

2004-06-01

To report the incidence and prognostic implications of obstructive uropathy (OU) in patients with advanced prostate cancer receiving androgen deprivation therapy and to define the impact initial local therapy has on the development of OU in patients with prostate cancer who develop recurrence and begin androgen deprivation therapy. From a population of 260 patients with advanced prostate cancer diagnosed between 1986 and 2003, OU was identified in 51 patients. The OU treatment options included ureteral stent, percutaneous nephrostomy, transurethral resection of the prostate, Foley catheter placement, and urinary diversion. Overall survival and the factors that influenced survival were calculated using standard statistical methods. OU was diagnosed in 15 (16%) of 80 patients who received local therapy with curative intent and in whom local therapy subsequently failed and in 36 (19%) of 180 patients who had never received local therapy (P = 0.7, chi-square test). Of these 51 patients, 39 had bladder neck obstruction and 16 had ureteral obstruction. Overall survival was significantly worse for the men with OU compared with those without OU (41 versus 54 months). OU was associated with tumor stage and androgen-insensitive prostate cancer. OU results in significantly reduced survival in men with prostate cancer. In a select group of patients with prostate cancer with progression after local therapy (primarily radiotherapy), no statistically significant reduction in the development of OU was observed relative to patients matched for stage, grade, and pretreatment prostate-specific antigen level treated with androgen deprivation therapy alone. Aggressive advanced stage and hormone-insensitive disease are variables associated with OU.

Birth tourism: socio-demographic and statistical aspects

Directory of Open Access Journals (Sweden)

Anatoly V. Korotkov

2016-01-01

Full Text Available The purpose of the study is to research birth tourism issue. The article gives the socio-demographic and statistical aspects of research problems of birth inbound tourism in the Russian Federation. Following the literature analysis, the degree of study for birth tourism lags behind its actual size. Currently, the media has accumulated a significant amount of information on birth tourism in Russia, that requires processing, systematization and understanding that can and should become an independent area of study of sociologists and demographers to develop recommendations for the management of socio-demographic processes in birth tourism in our country. It is necessary to identify the problems that will inevitably arise. At present, this process is almost not regulated.These problems are complex, it requires the joint efforts of sociologists and demographers. However, it is impossible to obtain reliable results and to develop management decisions without attention to the statistical aspect of this problem. It is necessary to create methodological support for collecting and information processing and model development of the birth tourism. At the initial stage it is necessary to identify the direction and objectives of the analysis to determine the factors in the development of this process, to develop a hierarchical system of statistical indicators, to receive the information, needed for calculating of specific indicators.The complex research of the birth tourism issues should be based on the methodology of sociology, demography and statistics, including statistical observation, interviews with residents, structure analysis and birth tourism concentration in the country, the analysis of the dynamics, classification of factors and reasons, the grouping of regions for the development of the studied processes and, of course, the development of economic-statistical indicators.The article reveals the problem of the significant influence of the

Analysis of investment factors which are influencing the growth of the Republic of Serbia

Directory of Open Access Journals (Sweden)

Milojević Ivan

2016-01-01

Full Text Available The subject of this research is empirical analysis of the factors which have influence on economic growth, whereas the main aim is to suggest adequate ways to overcome problems. We have analyzed the influence of budget deficit, personal consumption, inflation, real exchange rate, foreign trade balance and foreign direct investments (FDI on economic growth. Furthermore, we measured the influence factors on the presence and movement of the budget deficit. Research paper uses the data obtained from the Statistical Office of the Republic of Serbia, World Bank and the IMF for the time period 2001-2011 and has been applied regression analysis method. Research results indicate that the real exchange rate, personal consumption and foreign trade balance are statistically significant for anticipating economic growth developments. Contrary to our expectations, the empirical analysis showed that FDI have a negative influence on the economic growth. The coefficient 'public debt' is statistically significant and has a positive influence on the increase of budget deficit, whereas the increase of SDI and trade openness triggers a decrease in budget deficit. This research starts from the hypothesis that financing deficit limits economic growth and the inflow of FDI can't provide long-term economic growth. In the coming period Serbia needs to take advantage of the available resources and managing public finances, obeying laws and regulations and continuing with reforms are fundamental for achieving a stable business environment.

Statistical Frequency in Perception Affects Children’s Lexical Production

Science.gov (United States)

Richtsmeier, Peter T.; Gerken, LouAnn; Goffman, Lisa; Hogan, Tiffany

2009-01-01

Children’s early word production is influenced by the statistical frequency of speech sounds and combinations. Three experiments asked whether this production effect can be explained by a perceptual learning mechanism that is sensitive to word-token frequency and/or variability. Four-year-olds were exposed to nonwords that were either frequent (presented 10 times) or infrequent (presented once). When the frequent nonwords were spoken by the same talker, children showed no significant effect of perceptual frequency on production. When the frequent nonwords were spoken by different talkers, children produced them with fewer errors and shorter latencies. The results implicate token variability in perceptual learning. PMID:19338981

Synchronization from second order network connectivity statistics

Directory of Open Access Journals (Sweden)

Liqiong eZhao

2011-07-01

Full Text Available We investigate how network structure can influence the tendency for a neuronal network to synchronize, or its synchronizability, independent of the dynamical model for each neuron. The synchrony analysis takes advantage of the framework of second order networks (SONETs, which defines four second order connectivity statistics based on the relative frequency of two-connection network motifs. The analysis identifies two of these statistics, convergent connections and chain connections, as highly influencing the synchrony. Simulations verify that synchrony decreases with the frequency of convergent connections and increases with the frequency of chain connections. These trends persist with simulations of multiple models for the neuron dynamics and for different types of networks. Surprisingly, divergent connections, which determine the fraction of shared inputs, do not strongly influence the synchrony. The critical role of chains, rather than divergent connections, in influencing synchrony can be explained by a pool and redistribute mechanism. The pooling of many inputs averages out independent fluctuations, amplifying weak correlations in the inputs. With increased chain connections, neurons with many inputs tend to have many outputs. Hence, chains ensure that the amplified correlations in the neurons with many inputs are redistributed throughout the network, enhancing the development of synchrony across the network.

Statistical lamb wave localization based on extreme value theory

Science.gov (United States)

Harley, Joel B.

2018-04-01

Guided wave localization methods based on delay-and-sum imaging, matched field processing, and other techniques have been designed and researched to create images that locate and describe structural damage. The maximum value of these images typically represent an estimated damage location. Yet, it is often unclear if this maximum value, or any other value in the image, is a statistically significant indicator of damage. Furthermore, there are currently few, if any, approaches to assess the statistical significance of guided wave localization images. As a result, we present statistical delay-and-sum and statistical matched field processing localization methods to create statistically significant images of damage. Our framework uses constant rate of false alarm statistics and extreme value theory to detect damage with little prior information. We demonstrate our methods with in situ guided wave data from an aluminum plate to detect two 0.75 cm diameter holes. Our results show an expected improvement in statistical significance as the number of sensors increase. With seventeen sensors, both methods successfully detect damage with statistical significance.

Influence of topography on landscape radiation temperature distribution

International Nuclear Information System (INIS)

Florinsky, I.V.; Kulagina, T.B.; Meshalkina, J.L.

1994-01-01

The evaluation of the influence of topography on landscape radiation temperature distribution is carried out by statistical processing of digital models of elevation, gradient, aspect, horizontal, vertical and mean land surface curvatures and the infrared thermal scene generated by the Thermovision 880 system. Significant linear correlation coefficients between the landscape radiation temperature and elevation, slope, aspect, vertical and mean landsurface curvatures are determined, being —0-57, 0 38, 0-26, 015, 013, respectively. The equation of the topography influence on the distribution of the landscape radiation temperature is defined. (author)

Statistical methods and challenges in connectome genetics

KAUST Repository

Pluta, Dustin; Yu, Zhaoxia; Shen, Tong; Chen, Chuansheng; Xue, Gui; Ombao, Hernando

2018-01-01

The study of genetic influences on brain connectivity, known as connectome genetics, is an exciting new direction of research in imaging genetics. We here review recent results and current statistical methods in this area, and discuss some

[Analysis on influencing factor of the complications of percutaneous dilational tracheotomy].

Science.gov (United States)

Zhai, Xiang; Zhang, Jinling; Hang, Wei; Wang, Ming; Shi, Zhan; Mi, Yue; Hu, Yunlei; Liu, Gang

2015-01-01

To Analyze the influence factors on the complications of percutaneous dilational tracheotomy. Between August 2008 and February 2014, there were 3 450 patients with the indications of tracheotomy accepted percutaneous dilational tracheostomy, mainly using percutaneous dilational and percutaneous guide wire forceps in these cases. Statistical analysis was performed by SPSS 19.0 software on postoperative complications, the possible influence factors including age, gender, etiology, preoperative hypoxia, obesity, preoperative pulmonary infection, state of consciousness, operation method, operation doctor and whether with tracheal intubation. Among 3 450 patients, there were 164 cases with intraoperative or postoperative complications, including postoperative bleeding in 74 cases (2.14%), subcutaneous emphysema in 54 cases (1.57%), wound infection in 16 cases (0.46%), pneumothorax in 6 cases (0.17%), mediastinal emphysema in 5 cases (0.14%), operation failed and change to conventional incision in 4 cases (0.12%), tracheoesophageal fistula in 2 cases (0.06%), death in 3 cases(0.09%).Obesity, etiology, preoperative hypoxia, preoperative pulmonary infection, state of consciousness and operation method were the main influence factors, with significant statistical difference (χ(2) value was 0.010, 0.000, 0.002, 0.000, 0.000, 0.000, all P Gender, age, operation doctor and whether there was the endotracheal intubation were not the main influence factors. There was no significant statistical difference (P > 0.05). Although percutaneous dilational tracheostomy is safe, but the complications can also happen. In order to reduce the complications, it is need to pay attention to the factors of obesity, etiology, preoperative hypoxia, preoperative pulmonary infection, state of consciousness and operation method.

The influence of design characteristics on statistical inference in nonlinear estimation: A simulation study based on survival data and hazard modeling

DEFF Research Database (Denmark)

Andersen, J.S.; Bedaux, J.J.M.; Kooijman, S.A.L.M.

2000-01-01

This paper describes the influence of design characteristics on the statistical inference for an ecotoxicological hazard-based model using simulated survival data. The design characteristics of interest are the number and spacing of observations (counts) in time, the number and spacing of exposure...... concentrations (within c(min) and c(max)), and the initial number of individuals at time 0 in each concentration. A comparison of the coverage probabilities for confidence limits arising from the profile-likelihood approach and the Wald-based approach is carried out. The Wald-based approach is very sensitive...

[Delirium in stroke patients : Critical analysis of statistical procedures for the identification of risk factors].

Science.gov (United States)

Nydahl, P; Margraf, N G; Ewers, A

2017-04-01

Delirium is a relevant complication following an acute stroke. It is a multifactor occurrence with numerous interacting risk factors that alternately influence each other. The risk factors of delirium in stroke patients are often based on limited clinical studies. The statistical procedures and clinical relevance of delirium related risk factors in adult stroke patients should therefore be questioned. This secondary analysis includes clinically relevant studies that give evidence for the clinical relevance and statistical significance of delirium-associated risk factors in stroke patients. The quality of the reporting of regression analyses was assessed using Ottenbacher's quality criteria. The delirium-associated risk factors identified were examined with regard to statistical significance using the Bonferroni method of multiple testing for forming incorrect positive hypotheses. This was followed by a literature-based discussion on clinical relevance. Nine clinical studies were included. None of the studies fulfilled all the prerequisites and assumptions given for the reporting of regression analyses according to Ottenbacher. Of the 108 delirium-associated risk factors, a total of 48 (44.4%) were significant, whereby a total of 28 (58.3%) were false positive after Bonferroni correction. Following a literature-based discussion on clinical relevance, the assumption of statistical significance and clinical relevance could be found for only four risk factors (dementia or cognitive impairment, total anterior infarct, severe infarct and infections). The statistical procedures used in the existing literature are questionable, as are their results. A post-hoc analysis and critical appraisal reduced the number of possible delirium-associated risk factors to just a few clinically relevant factors.

Statistical Properties of Online Auctions

Science.gov (United States)

Namazi, Alireza; Schadschneider, Andreas

We characterize the statistical properties of a large number of online auctions run on eBay. Both stationary and dynamic properties, like distributions of prices, number of bids etc., as well as relations between these quantities are studied. The analysis of the data reveals surprisingly simple distributions and relations, typically of power-law form. Based on these findings we introduce a simple method to identify suspicious auctions that could be influenced by a form of fraud known as shill bidding. Furthermore the influence of bidding strategies is discussed. The results indicate that the observed behavior is related to a mixture of agents using a variety of strategies.

The significance of Good Chair as part of children’s school and home environment in the preventive treatment of body statistics distortions

OpenAIRE

Mirosław Mrozkowiak; Hanna Żukowska

2015-01-01

Mrozkowiak Mirosław, Żukowska Hanna. Znaczenie Dobrego Krzesła, jako elementu szkolnego i domowego środowiska ucznia, w profilaktyce zaburzeń statyki postawy ciała = The significance of Good Chair as part of children’s school and home environment in the preventive treatment of body statistics distortions. Journal of Education, Health and Sport. 2015;5(7):179-215. ISSN 2391-8306. DOI 10.5281/zenodo.19832 http://ojs.ukw.edu.pl/index.php/johs/article/view/2015%3B5%287%29%3A179-215 https:...

Can a significance test be genuinely Bayesian?

OpenAIRE

Pereira, Carlos A. de B.; Stern, Julio Michael; Wechsler, Sergio

2008-01-01

The Full Bayesian Significance Test, FBST, is extensively reviewed. Its test statistic, a genuine Bayesian measure of evidence, is discussed in detail. Its behavior in some problems of statistical inference like testing for independence in contingency tables is discussed.

Factors influencing the career success of professional and business women in South Africa

Directory of Open Access Journals (Sweden)

Marianne Doubell

2014-11-01

Full Text Available This article reports on an empirical study that investigated factors influencing women’s career success. Statistics relating to the field of women in management indicate that, worldwide, women are underrepresented in executive and decision-making positions. Women face unique challenges in their career pursuit that may prevent them from moving up to executive positions. A framework to investigate the factors influencing career success indicates that factors such as demographics, personality, culture, barriers, external and internal support impact on the career success of women. This study surveyed a sample of 301 professional and business women in South Africa. The results of the empirical survey showed that there are statistical significant relationships between groups of women based on their demographics and their perceptions of the factors that influence their career success.

Statistics anxiety among undergraduate students in the faculty of ...

African Journals Online (AJOL)

The purpose of the study was to determine the level of statistics anxiety among undergraduate students, and whether the level of influenced by factor e.g gender and age. A sample of 100 third year students who enrolled for basic statistics in the University of Calabar was used for the study. A series of t-tests revealed that the ...

Influences of credibility of testimony and strength of statistical evidence on children's and adolescents' reasoning.

Science.gov (United States)

Kail, Robert V

2013-11-01

According to dual-process models that include analytic and heuristic modes of processing, analytic processing is often expected to become more common with development. Consistent with this view, on reasoning problems, adolescents are more likely than children to select alternatives that are backed by statistical evidence. It is shown here that this pattern depends on the quality of the statistical evidence and the quality of the testimonial that is the typical alternative to statistical evidence. In Experiment 1, 9- and 13-year-olds (N=64) were presented with scenarios in which solid statistical evidence was contrasted with casual or expert testimonial evidence. When testimony was casual, children relied on it but adolescents did not; when testimony was expert, both children and adolescents relied on it. In Experiment 2, 9- and 13-year-olds (N=83) were presented with scenarios in which casual testimonial evidence was contrasted with weak or strong statistical evidence. When statistical evidence was weak, children and adolescents relied on both testimonial and statistical evidence; when statistical evidence was strong, most children and adolescents relied on it. Results are discussed in terms of their implications for dual-process accounts of cognitive development. Copyright © 2013 Elsevier Inc. All rights reserved.

Spatio-temporal statistical models with applications to atmospheric processes

International Nuclear Information System (INIS)

Wikle, C.K.

1996-01-01

This doctoral dissertation is presented as three self-contained papers. An introductory chapter considers traditional spatio-temporal statistical methods used in the atmospheric sciences from a statistical perspective. Although this section is primarily a review, many of the statistical issues considered have not been considered in the context of these methods and several open questions are posed. The first paper attempts to determine a means of characterizing the semiannual oscillation (SAO) spatial variation in the northern hemisphere extratropical height field. It was discovered that the midlatitude SAO in 500hPa geopotential height could be explained almost entirely as a result of spatial and temporal asymmetries in the annual variation of stationary eddies. It was concluded that the mechanism for the SAO in the northern hemisphere is a result of land-sea contrasts. The second paper examines the seasonal variability of mixed Rossby-gravity waves (MRGW) in lower stratospheric over the equatorial Pacific. Advanced cyclostationary time series techniques were used for analysis. It was found that there are significant twice-yearly peaks in MRGW activity. Analyses also suggested a convergence of horizontal momentum flux associated with these waves. In the third paper, a new spatio-temporal statistical model is proposed that attempts to consider the influence of both temporal and spatial variability. This method is mainly concerned with prediction in space and time, and provides a spatially descriptive and temporally dynamic model

Statistical Analysis of the Factors Influencing the Recurrence of ...

African Journals Online (AJOL)

Objective To evaluate the risk factors influencing the recurrence of urinary bladder cancer, and to predict the probability of recurrence within two years after radical cystectomy. Patients and Methods Between 1986 and 1994, 857 patients were admitted at the Urology and Nephrology Center of Mansoura University, Egypt, ...

Current and future health care professionals attitudes toward and knowledge of statistics: How confidence influences learning.

Science.gov (United States)

Baghi, Heibatollah; Kornides, Melanie L

2013-01-01

Health care professionals require some understanding of statistics to successfully implement evidence based practice. Developing competency in statistical reasoning is necessary for students training in health care administration, research, and clinical care. Recently, the interest in healthcare professional's attitudes toward statistics has increased substantially due to evidence that these attitudes can hinder professionalism developing an understanding of statistical concepts. In this study, we analyzed pre- and post-instruction attitudes towards and knowledge of statistics obtained from health science graduate students, including nurses and nurse practitioners, enrolled in an introductory graduate course in statistics (n = 165). Results show that the students already held generally positive attitudes toward statistics at the beginning of course. However, these attitudes-along with the students' statistical proficiency-improved after 10 weeks of instruction. The results have implications for curriculum design and delivery methods as well as for health professionals' effective use of statistics in critically evaluating and utilizing research in their practices.

New selection effect of statistical investigations of supernova remnants

International Nuclear Information System (INIS)

Allakhverdiev, A.O.; Gusejnov, O.Kh.; Kasumov, F.K.

1986-01-01

The influence of H2 regions on the parameters of Supernova remnants (SNR) is investigated. It has been shown that the projection of such regions on the SNRs leads to local changes of morphological structure of young shell-type SNRs and considerable distortions of integral parameters of evolved shell-type SNRs (with D > 10 pc) and plerions, up to their complete undetectability on the background of classical and gigantic H2 regions. A new selection effect, in fact, arises from these factors connected with additional limitations made by the real structure of the interstellar medium on the statistical investigations of SNRs. The influence of this effect on the statistical completeness of objects has been estimated

New selection effect in statistical investigations of supernova remnants

Science.gov (United States)

Allakhverdiev, A. O.; Guseinov, O. Kh.; Kasumov, F. K.

1986-01-01

The influence of H II regions on the parameters of supernova remnants (SNR) is investigated. It has been shown that the projection of such regions on the SNRs leads to: a) local changes of morphological structure of young shell-type SNRs and b) considerable distortions of integral parameters of evolved shell-type SNRs (with D > 10 pc) and plerions, up to their complete undetectability on the background of classical and gigantic H II regions. A new selection effect, in fact, arises from these factors connected with additional limitations made by the real structure of the interstellar medium on the statistical investigations of SNRs. The influence of this effect on the statistical completeness of objects has been estimated.

Studying the Factors Influencing a Choice of Devices for Carrying Out Inhalations on the Basis of Statistical Processing of Results Of Questionnaire

Directory of Open Access Journals (Sweden)

Galina A. Kharchenko

2016-05-01

Full Text Available Authors set the object, to study the factors influencing a choice of buyers of devices for carrying out inhalation on the basis of statistical processing of results of questionnaire of buyers, to analyze interrelation between the factors influencing a choice and purchase of the device and gender and age characteristics of potential buyers. The role of the doctor, worker of a drugstore, the Internet sites in the course of a choice, opinion of consumers of different age categories on the most preferable sources of information on devices for carrying out inhalation is revealed, preferences of buyers at a choice of a place of commission of purchase of devices for carrying out inhalation are defined. Feature of respondents of sources of information and making decision on purchase, female and male concerning use is shown.

Statistics for experimentalists

CERN Document Server

Cooper, B E

2014-01-01

Statistics for Experimentalists aims to provide experimental scientists with a working knowledge of statistical methods and search approaches to the analysis of data. The book first elaborates on probability and continuous probability distributions. Discussions focus on properties of continuous random variables and normal variables, independence of two random variables, central moments of a continuous distribution, prediction from a normal distribution, binomial probabilities, and multiplication of probabilities and independence. The text then examines estimation and tests of significance. Topics include estimators and estimates, expected values, minimum variance linear unbiased estimators, sufficient estimators, methods of maximum likelihood and least squares, and the test of significance method. The manuscript ponders on distribution-free tests, Poisson process and counting problems, correlation and function fitting, balanced incomplete randomized block designs and the analysis of covariance, and experiment...

Non-extensive statistical effects in nuclear many-body problems

International Nuclear Information System (INIS)

Lavagno, A.; Quarati, P.

2007-01-01

Density and temperature conditions in many stellar core and in the first stage of relativistic heavy-ion collisions imply the presence of non-ideal plasma effects with memory and long-range interactions between particles. Recent progress in statistical mechanics indicates that Tsallis non-extensive thermostatistics could be the natural generalization of the standard classical and quantum statistics, when memory effects and long range forces are not negligible. In this framework, we show that in weakly non-ideal plasma non-extensive effects should be taken into account to derive the equilibrium distribution functions, the quantum fluctuations and correlations between the particles. The strong influence of these effects is discussed in the context of the solar plasma physics and in the high-energy nuclear-nuclear collision experiments. Although the deviation from Boltzmann-Gibbs statistics, in both cases, is very small, the stellar plasma and the hadronic gas are strongly influenced by the non-extensive feature and the discrepancies between experimental data and theoretical previsions are sensibly reduced. (authors)

[Statistical analysis of articles in "Chinese journal of applied physiology" from 1999 to 2008].

Science.gov (United States)

Du, Fei; Fang, Tao; Ge, Xue-ming; Jin, Peng; Zhang, Xiao-hong; Sun, Jin-li

2010-05-01

To evaluate the academic level and influence of "Chinese Journal of Applied Physiology" through statistical analysis for the fund sponsored articles published in the recent ten years. The articles of "Chinese Journal of Applied Physiology" from 1999 to 2008 were investigated. The number and the percentage of the fund sponsored articles, the fund organization and the author region were quantitatively analyzed by using the literature metrology method. The number of the fund sponsored articles increased unceasingly. The ratio of the fund from local government significantly enhanced in the latter five years. Most of the articles were from institutes located at Beijing, Zhejiang and Tianjin. "Chinese Journal of Applied Physiology" has a fine academic level and social influence.

The Influence of Family and Significant Others on Women's Decisions to Obtain an Abortion: A Study of a Northwest Louisiana Abortion Clinic

Science.gov (United States)

Solomon, Bertina Loutrice

2011-01-01

This study researched whether family members and significant others influence a woman's decision to obtain an abortion. Influence is defined by Merriam-Webster (2011) as the power or capacity of causing an effect in indirect or intangible ways; power exerted over the minds or behaviors of others. The theoretical framework that will be used in…

Primary and secondary cases in Escherichia coli O157 outbreaks: a statistical analysis.

LENUS (Irish Health Repository)

Snedeker, Kate G

2009-01-01

BACKGROUND: Within outbreaks of Escherichia coli O157 (E. coli O157), at least 10-15% of cases are thought to have been acquired by secondary transmission. However, there has been little systematic quantification or characterisation of secondary outbreak cases worldwide. The aim of this study was to characterise secondary outbreak cases, estimate the overall proportion of outbreak cases that were the result of secondary transmission and to analyse the relationships between primary and secondary outbreak cases by mode of transmission, country and median age. METHODS: Published data was obtained from 90 confirmed Escherichia coli O157 outbreaks in Great Britain, Ireland, Scandinavia, Canada, the United States and Japan, and the outbreaks were described in terms of modes of primary and secondary transmission, country, case numbers and median case age. Outbreaks were tested for statistically significant differences in the number of ill, confirmed, primary and secondary cases (analysis of variance and Kruskal-Wallis) and in the rate of secondary cases between these variables (Generalised Linear Models). RESULTS: The outbreaks had a median of 13.5 confirmed cases, and mean proportion of 0.195 secondary cases. There were statistically significant differences in the numbers of ill, confirmed, primary and secondary cases between modes of primary transmission (p < 0.021), and in primary and secondary cases between median age categories (p < 0.039) and modes of secondary transmission (p < 0.001).Secondary case rates differed statistically significantly between modes of secondary and primary transmission and median age categories (all p < 0.001), but not between countries (p = 0.23). Statistically significantly higher rates of secondary transmission were found in outbreaks with a median age <6 years and those with secondary transmission via person to person spread in nurseries. No statistically significant interactions were found between country, mode of transmission and age

On two methods of statistical image analysis

NARCIS (Netherlands)

Missimer, J; Knorr, U; Maguire, RP; Herzog, H; Seitz, RJ; Tellman, L; Leenders, K.L.

1999-01-01

The computerized brain atlas (CBA) and statistical parametric mapping (SPM) are two procedures for voxel-based statistical evaluation of PET activation studies. Each includes spatial standardization of image volumes, computation of a statistic, and evaluation of its significance. In addition,

Influence of a prolonged fasting and mild activity on routine laboratory tests.

Science.gov (United States)

Šupak-Smolčić, Vesna; Antončić, Dragana; Ožanić, Doris; Vladilo, Ivana; Bilić-Zulle, Lidija

2015-01-01

Despite the standardization of the phlebotomy procedure, blood analysis is occasionally requested after recommended hours with the excuse that the patient is still fasting. We aimed to examine the influence of prolonged fasting and mild physical activity on routine laboratory tests. The study was conducted on 30 volunteers (27 female) median age 40y (20-59). Blood samples were taken in the morning (7:00-8:00a.m.) and early afternoon (1:00-2:00p.m.) after prolonged fasting and usual daily activities. Serum glucose (GLU), urea, creatinine, triglyceride, uric acid (UA), iron and electrolytes were analyzed on Roche cobas 6000 c501 and complete blood count on Siemens ADVIA 2120i. Statistical significance between the two measurements was tested using paired t-test or Wilcoxon test according to data distribution. Clinical significance was judged against calculated reference change values (RCV). A statistically significant decrease was found for red blood cell count, hemoglobin, hematocrit, mean corpuscular volume (MCV), GLU, urea, creatinine, triglycerides and electrolytes, whereas white blood cell count and iron were significantly increased. Judging against desirable bias derived from biological variation, a significant change was found for all the analytes except MCV, platelet count, UA and triglycerides. A clinically significant change was not found for any of the tested analytes when compared to RCV. Prolonged fasting and mild activity will not influence the medical decision for healthy subjects with normal results. Despite the present statistically significant change, the clinically significant change was not shown. However, the study did not include pathological results which have to be interpreted more carefully. Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Use of statistic control of the process as part of a quality assurance plan

International Nuclear Information System (INIS)

Acosta, S.; Lewis, C.

2013-01-01

One of the technical requirements of the standard IRAM ISO 17025 for the accreditation of testing laboratories, is the assurance of the quality of the results through the control and monitoring of the factors influencing the reliability of them. The grade the factors contribute to the total measurement uncertainty, determines which of them should be considered when developing a quality assurance plan. The laboratory of environmental measurements of strontium-90 in the accreditation process, performs most of its determinations in samples with values close to the detection limit. For this reason the correct characterization of the white, is a critical parameter and is verified through a letter for statistical process control. The scope of the present work is concerned the control of whites and so it was collected a statistically significant amount of data, for a period of time that is covered of different conditions. This allowed consider significant variables in the process, such as temperature and humidity, and build a graph of white control, which forms the basis of a statistical process control. The data obtained were lower and upper limits for the preparation of the charter white control. In this way the process of characterization of white was considered to operate under statistical control and concludes that it can be used as part of a plan of insurance of the quality

Statistics Using Just One Formula

Science.gov (United States)

Rosenthal, Jeffrey S.

2018-01-01

This article advocates that introductory statistics be taught by basing all calculations on a single simple margin-of-error formula and deriving all of the standard introductory statistical concepts (confidence intervals, significance tests, comparisons of means and proportions, etc) from that one formula. It is argued that this approach will…

Statistics Anxiety among Postgraduate Students

Science.gov (United States)

Koh, Denise; Zawi, Mohd Khairi

2014-01-01

Most postgraduate programmes, that have research components, require students to take at least one course of research statistics. Not all postgraduate programmes are science based, there are a significant number of postgraduate students who are from the social sciences that will be taking statistics courses, as they try to complete their…

The influence of socio cultural dynamics on convergence communication of aquaculture agribusiness actors

Science.gov (United States)

Oktavia, Y.

2018-03-01

This research aims to: (1) Analyze the level of socio-cultural dynamics of agibusiness aquaculture actors. (2) Analyze the influence of socio-cultural dynamics on convergence communication of capacity development of aquaculture agribusiness actors.Data was collected by questionnaire and interview of group members on agribusiness. Data analyze was done by descriptive and inferential statistics with using SEM method. The result of descriptive statistics on 284 agribusiness members showed that: Socio-cultural dynamics of agibusiness aquaculture actors was in low category, as shown by lack of the role of customary institutions and quality of local leadership.The communication convergence is significantly and positively influenced by the communication behavior of agribusiness actors in access information.

Statistical methods and challenges in connectome genetics

KAUST Repository

Pluta, Dustin

2018-03-12

The study of genetic influences on brain connectivity, known as connectome genetics, is an exciting new direction of research in imaging genetics. We here review recent results and current statistical methods in this area, and discuss some of the persistent challenges and possible directions for future work.

A statistical skull geometry model for children 0-3 years old.

Directory of Open Access Journals (Sweden)

Zhigang Li

Full Text Available Head injury is the leading cause of fatality and long-term disability for children. Pediatric heads change rapidly in both size and shape during growth, especially for children under 3 years old (YO. To accurately assess the head injury risks for children, it is necessary to understand the geometry of the pediatric head and how morphologic features influence injury causation within the 0-3 YO population. In this study, head CT scans from fifty-six 0-3 YO children were used to develop a statistical model of pediatric skull geometry. Geometric features important for injury prediction, including skull size and shape, skull thickness and suture width, along with their variations among the sample population, were quantified through a series of image and statistical analyses. The size and shape of the pediatric skull change significantly with age and head circumference. The skull thickness and suture width vary with age, head circumference and location, which will have important effects on skull stiffness and injury prediction. The statistical geometry model developed in this study can provide a geometrical basis for future development of child anthropomorphic test devices and pediatric head finite element models.

A statistical skull geometry model for children 0-3 years old.

Science.gov (United States)

Li, Zhigang; Park, Byoung-Keon; Liu, Weiguo; Zhang, Jinhuan; Reed, Matthew P; Rupp, Jonathan D; Hoff, Carrie N; Hu, Jingwen

2015-01-01

Head injury is the leading cause of fatality and long-term disability for children. Pediatric heads change rapidly in both size and shape during growth, especially for children under 3 years old (YO). To accurately assess the head injury risks for children, it is necessary to understand the geometry of the pediatric head and how morphologic features influence injury causation within the 0-3 YO population. In this study, head CT scans from fifty-six 0-3 YO children were used to develop a statistical model of pediatric skull geometry. Geometric features important for injury prediction, including skull size and shape, skull thickness and suture width, along with their variations among the sample population, were quantified through a series of image and statistical analyses. The size and shape of the pediatric skull change significantly with age and head circumference. The skull thickness and suture width vary with age, head circumference and location, which will have important effects on skull stiffness and injury prediction. The statistical geometry model developed in this study can provide a geometrical basis for future development of child anthropomorphic test devices and pediatric head finite element models.

To the problem of the statistical basis of evaluation of the mechanical safety factor

International Nuclear Information System (INIS)

Tsyganov, S.V.

2009-01-01

The methodology applied for the safety factor assessment of the WWER fuel cycles uses methods and terms of statistics. Value of the factor is calculated on the basis of estimation of probability to meet predefined limits. Such approach demands the special attention to the statistical properties of parameters of interest. Considering the mechanical constituents of the engineering factor it is assumed uncertainty factors of safety parameters are stochastic values. It characterized by probabilistic distributions that can be unknown. Traditionally in the safety factor assessment process the unknown parameters are estimated from the conservative points of view. This paper analyses how the refinement of the factors distribution parameters is important for the assessment of the mechanical safety factor. For the analysis the statistical approach is applied for modelling of different type of factor probabilistic distributions. It is shown the significant influence of the shape and parameters of distributions for some factors on the value of mechanical safety factor. (Authors)

To the problem of the statistical basis of evaluation of the mechanical safety factor

International Nuclear Information System (INIS)

Tsyganov, S.

2009-01-01

The methodology applied for the safety factor assessment of the VVER fuel cycles uses methods and terms of statistics. Value of the factor is calculated on the basis of estimation of probability to meet predefined limits. Such approach demands the special attention to the statistical properties of parameters of interest. Considering the mechanical constituents of the engineering factor it is assumed uncertainty factors of safety parameters are stochastic values. It characterized by probabilistic distributions that can be unknown. Traditionally in the safety factor assessment process the unknown parameters are estimated from the conservative points of view. This paper analyses how the refinement of the factors distribution parameters is important for the assessment of the mechanical safety factor. For the analysis the statistical approach is applied for modelling of different type of factor probabilistic distributions. It is shown the significant influence of the shape and parameters of distributions for some factors on the value of mechanical safety factor. (author)

Statistical Reporting Errors and Collaboration on Statistical Analyses in Psychological Science.

Science.gov (United States)

Veldkamp, Coosje L S; Nuijten, Michèle B; Dominguez-Alvarez, Linda; van Assen, Marcel A L M; Wicherts, Jelte M

2014-01-01

Statistical analysis is error prone. A best practice for researchers using statistics would therefore be to share data among co-authors, allowing double-checking of executed tasks just as co-pilots do in aviation. To document the extent to which this 'co-piloting' currently occurs in psychology, we surveyed the authors of 697 articles published in six top psychology journals and asked them whether they had collaborated on four aspects of analyzing data and reporting results, and whether the described data had been shared between the authors. We acquired responses for 49.6% of the articles and found that co-piloting on statistical analysis and reporting results is quite uncommon among psychologists, while data sharing among co-authors seems reasonably but not completely standard. We then used an automated procedure to study the prevalence of statistical reporting errors in the articles in our sample and examined the relationship between reporting errors and co-piloting. Overall, 63% of the articles contained at least one p-value that was inconsistent with the reported test statistic and the accompanying degrees of freedom, and 20% of the articles contained at least one p-value that was inconsistent to such a degree that it may have affected decisions about statistical significance. Overall, the probability that a given p-value was inconsistent was over 10%. Co-piloting was not found to be associated with reporting errors.

An in vivo assessment of the influence of needle gauges on endodontic irrigation flow rate.

Science.gov (United States)

Gopikrishna, Velayutham; Sibi, Swamy; Archana, Durvasulu; Pradeep Kumar, Angabakkam Rajasekaran; Narayanan, Lakshmi

2016-01-01

The aim of this clinical study was to assess the influence of irrigation needle gauge on endodontic irrigation flow rates. In vivo assessment. Five specialist endodontists performed intracanal irrigation procedures on 50 mesiobuccal canal of mandibular first molars using three different irrigation needle gauges. Data of time taken for irrigation was recorded by an irrigation testing system and analyzed using independent sample "T" test and one-way analysis of variance (ANOVA) test. The level of significance was set at P < 0.05. The following tests were used for the statistical analysis: Independent sample "T" test, one-way ANOVA test, and post hoc multiple comparison was carried out using Tukey's honest significant difference (HSD) test using Statistical Package for the Social Sciences (SPSS) version 16 for Windows. The average flow rate of 26 gauge was 0.27 mLs(-1), of 27 gauge was 0.19 mLs(-1), and of 30 gauge was 0.09 mls(-1). There was statistical significance among the gauges (P < 0.001). 26 gauge had highest flow rate when compared with other groups followed by 27 gauge and 30 gauge respectively. The operator variability for flow rate of three endodontic irrigation needle gauges (26 gauge, 27 gauge, and 30 gauge) was found to be not significant. Needle gauge has significant influence on endodontic irrigation flow rate.

Scalar statistics in variable property turbulent channel flows

NARCIS (Netherlands)

Patel, A.; Boersma, B.J.; Pecnik, R.

2017-01-01

Direct numerical simulation of fully developed, internally heated channel flows with isothermal walls is performed using the low-Mach-number approximation of Navier-Stokes equation to investigate the influence of temperature-dependent properties on turbulent scalar statistics. Different constitutive

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.

A tilting approach to ranking influence

KAUST Repository

Genton, Marc G.

2014-12-01

We suggest a new approach, which is applicable for general statistics computed from random samples of univariate or vector-valued or functional data, to assessing the influence that individual data have on the value of a statistic, and to ranking the data in terms of that influence. Our method is based on, first, perturbing the value of the statistic by ‘tilting’, or reweighting, each data value, where the total amount of tilt is constrained to be the least possible, subject to achieving a given small perturbation of the statistic, and, then, taking the ranking of the influence of data values to be that which corresponds to ranking the changes in data weights. It is shown, both theoretically and numerically, that this ranking does not depend on the size of the perturbation, provided that the perturbation is sufficiently small. That simple result leads directly to an elegant geometric interpretation of the ranks; they are the ranks of the lengths of projections of the weights onto a ‘line’ determined by the first empirical principal component function in a generalized measure of covariance. To illustrate the generality of the method we introduce and explore it in the case of functional data, where (for example) it leads to generalized boxplots. The method has the advantage of providing an interpretable ranking that depends on the statistic under consideration. For example, the ranking of data, in terms of their influence on the value of a statistic, is different for a measure of location and for a measure of scale. This is as it should be; a ranking of data in terms of their influence should depend on the manner in which the data are used. Additionally, the ranking recognizes, rather than ignores, sign, and in particular can identify left- and right-hand ‘tails’ of the distribution of a random function or vector.

Statistics 101 for Radiologists.

Science.gov (United States)

Anvari, Arash; Halpern, Elkan F; Samir, Anthony E

2015-10-01

Diagnostic tests have wide clinical applications, including screening, diagnosis, measuring treatment effect, and determining prognosis. Interpreting diagnostic test results requires an understanding of key statistical concepts used to evaluate test efficacy. This review explains descriptive statistics and discusses probability, including mutually exclusive and independent events and conditional probability. In the inferential statistics section, a statistical perspective on study design is provided, together with an explanation of how to select appropriate statistical tests. Key concepts in recruiting study samples are discussed, including representativeness and random sampling. Variable types are defined, including predictor, outcome, and covariate variables, and the relationship of these variables to one another. In the hypothesis testing section, we explain how to determine if observed differences between groups are likely to be due to chance. We explain type I and II errors, statistical significance, and study power, followed by an explanation of effect sizes and how confidence intervals can be used to generalize observed effect sizes to the larger population. Statistical tests are explained in four categories: t tests and analysis of variance, proportion analysis tests, nonparametric tests, and regression techniques. We discuss sensitivity, specificity, accuracy, receiver operating characteristic analysis, and likelihood ratios. Measures of reliability and agreement, including κ statistics, intraclass correlation coefficients, and Bland-Altman graphs and analysis, are introduced. © RSNA, 2015.

Preventing statistical errors in scientific journals.

NARCIS (Netherlands)

Nuijten, M.B.

2016-01-01

There is evidence for a high prevalence of statistical reporting errors in psychology and other scientific fields. These errors display a systematic preference for statistically significant results, distorting the scientific literature. There are several possible causes for this systematic error

Basics of statistical physics

CERN Document Server

Müller-Kirsten, Harald J W

2013-01-01

Statistics links microscopic and macroscopic phenomena, and requires for this reason a large number of microscopic elements like atoms. The results are values of maximum probability or of averaging. This introduction to statistical physics concentrates on the basic principles, and attempts to explain these in simple terms supplemented by numerous examples. These basic principles include the difference between classical and quantum statistics, a priori probabilities as related to degeneracies, the vital aspect of indistinguishability as compared with distinguishability in classical physics, the differences between conserved and non-conserved elements, the different ways of counting arrangements in the three statistics (Maxwell-Boltzmann, Fermi-Dirac, Bose-Einstein), the difference between maximization of the number of arrangements of elements, and averaging in the Darwin-Fowler method. Significant applications to solids, radiation and electrons in metals are treated in separate chapters, as well as Bose-Eins...

Renyi statistics in equilibrium statistical mechanics

International Nuclear Information System (INIS)

Parvan, A.S.; Biro, T.S.

2010-01-01

The Renyi statistics in the canonical and microcanonical ensembles is examined both in general and in particular for the ideal gas. In the microcanonical ensemble the Renyi statistics is equivalent to the Boltzmann-Gibbs statistics. By the exact analytical results for the ideal gas, it is shown that in the canonical ensemble, taking the thermodynamic limit, the Renyi statistics is also equivalent to the Boltzmann-Gibbs statistics. Furthermore it satisfies the requirements of the equilibrium thermodynamics, i.e. the thermodynamical potential of the statistical ensemble is a homogeneous function of first degree of its extensive variables of state. We conclude that the Renyi statistics arrives at the same thermodynamical relations, as those stemming from the Boltzmann-Gibbs statistics in this limit.

Influences of credibility of testimony and strength of statistical evidence on children’s and adolescents’ reasoning

Science.gov (United States)

Kail, Robert V.

2013-01-01

According to dual-process models that include analytic and heuristic modes of processing, analytic processing is often expected to become more common with development. Consistent with this view, on reasoning problems, adolescents are more likely than children to select alternatives that are backed by statistical evidence. It is shown here that this pattern depends on the quality of the statistical evidence and the quality of the testimonial that is the typical alternative to statistical evidence. In Experiment 1, 9- and 13-year-olds (N = 64) were presented with scenarios in which solid statistical evidence was contrasted with casual or expert testimonial evidence. When testimony was casual, children relied on it but adolescents did not; when testimony was expert, both children and adolescents relied on it. In Experiment 2, 9- and 13-year-olds (N = 83) were presented with scenarios in which casual testimonial evidence was contrasted with weak or strong statistical evidence. When statistical evidence was weak, children and adolescents relied on both testimonial and statistical evidence; when statistical evidence was strong, most children and adolescents relied on it. Results are discussed in terms of their implications for dual-process accounts of cognitive development. PMID:23735681

Proceedings of the 1980 DOE statistical symposium

International Nuclear Information System (INIS)

Truett, T.; Margolies, D.; Mensing, R.W.

1981-04-01

Separate abstracts were prepared for 8 of the 16 papers presented at the DOE Statistical Symposium in California in October 1980. The topics of those papers not included cover the relative detection efficiency on sets of irradiated fuel elements, estimating failure rates for pumps in nuclear reactors, estimating fragility functions, application of bounded-influence regression, the influence function method applied to energy time series data, reliability problems in power generation systems and uncertainty analysis associated with radioactive waste disposal. The other 8 papers have previously been added to the data base

Career Choice And College Students: Parental Influence on Career Choice Traditionalism among College Students in Selected Cities in Ethiopia

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Sella Kumar

2016-09-01

Full Text Available The study explored the influence of parents on choosing career among college students in selected private colleges situated around Bahirdar City, Ethiopia. Choosing a suitable career is a vital part in every student’s life. Further, it ignites a person’s future life for his/her own job preference and life style. In this context, influence of social members is inevitable; generally the influence of family members and most particularly parents play a major role as an influencer and determiner on choosing a career option. Students in Ethiopia are not exceptional to this phenomenon of selecting right and suitable career. A cross-sectional survey design was adopted and multi stage sampling technique was employed to identify the participants. Totally, 175 participants (Male=99 and (Female =76 responded to Holland Personality Inventory (Holland, 1997 and Career Choice Traditionalism Scale (Hensely, 2003. The collected data were statistically processed using SPSS version 16. Descriptive and inferential statistics was employed to analyze the data. The results revealed that there is a significant influence of parents on career choice among students. Specifically, father’s influence is found to be more significant on career choice decision making among students than their mothers.

High cumulants of conserved charges and their statistical uncertainties

Science.gov (United States)

Li-Zhu, Chen; Ye-Yin, Zhao; Xue, Pan; Zhi-Ming, Li; Yuan-Fang, Wu

2017-10-01

We study the influence of measured high cumulants of conserved charges on their associated statistical uncertainties in relativistic heavy-ion collisions. With a given number of events, the measured cumulants randomly fluctuate with an approximately normal distribution, while the estimated statistical uncertainties are found to be correlated with corresponding values of the obtained cumulants. Generally, with a given number of events, the larger the cumulants we measure, the larger the statistical uncertainties that are estimated. The error-weighted averaged cumulants are dependent on statistics. Despite this effect, however, it is found that the three sigma rule of thumb is still applicable when the statistics are above one million. Supported by NSFC (11405088, 11521064, 11647093), Major State Basic Research Development Program of China (2014CB845402) and Ministry of Science and Technology (MoST) (2016YFE0104800)

A Statistical Graphical Model of the California Reservoir System

Science.gov (United States)

Taeb, A.; Reager, J. T.; Turmon, M.; Chandrasekaran, V.

2017-11-01

The recent California drought has highlighted the potential vulnerability of the state's water management infrastructure to multiyear dry intervals. Due to the high complexity of the network, dynamic storage changes in California reservoirs on a state-wide scale have previously been difficult to model using either traditional statistical or physical approaches. Indeed, although there is a significant line of research on exploring models for single (or a small number of) reservoirs, these approaches are not amenable to a system-wide modeling of the California reservoir network due to the spatial and hydrological heterogeneities of the system. In this work, we develop a state-wide statistical graphical model to characterize the dependencies among a collection of 55 major California reservoirs across the state; this model is defined with respect to a graph in which the nodes index reservoirs and the edges specify the relationships or dependencies between reservoirs. We obtain and validate this model in a data-driven manner based on reservoir volumes over the period 2003-2016. A key feature of our framework is a quantification of the effects of external phenomena that influence the entire reservoir network. We further characterize the degree to which physical factors (e.g., state-wide Palmer Drought Severity Index (PDSI), average temperature, snow pack) and economic factors (e.g., consumer price index, number of agricultural workers) explain these external influences. As a consequence of this analysis, we obtain a system-wide health diagnosis of the reservoir network as a function of PDSI.

Statistical analysis of brake squeal noise

Science.gov (United States)

Oberst, S.; Lai, J. C. S.

2011-06-01

Despite substantial research efforts applied to the prediction of brake squeal noise since the early 20th century, the mechanisms behind its generation are still not fully understood. Squealing brakes are of significant concern to the automobile industry, mainly because of the costs associated with warranty claims. In order to remedy the problems inherent in designing quieter brakes and, therefore, to understand the mechanisms, a design of experiments study, using a noise dynamometer, was performed by a brake system manufacturer to determine the influence of geometrical parameters (namely, the number and location of slots) of brake pads on brake squeal noise. The experimental results were evaluated with a noise index and ranked for warm and cold brake stops. These data are analysed here using statistical descriptors based on population distributions, and a correlation analysis, to gain greater insight into the functional dependency between the time-averaged friction coefficient as the input and the peak sound pressure level data as the output quantity. The correlation analysis between the time-averaged friction coefficient and peak sound pressure data is performed by applying a semblance analysis and a joint recurrence quantification analysis. Linear measures are compared with complexity measures (nonlinear) based on statistics from the underlying joint recurrence plots. Results show that linear measures cannot be used to rank the noise performance of the four test pad configurations. On the other hand, the ranking of the noise performance of the test pad configurations based on the noise index agrees with that based on nonlinear measures: the higher the nonlinearity between the time-averaged friction coefficient and peak sound pressure, the worse the squeal. These results highlight the nonlinear character of brake squeal and indicate the potential of using nonlinear statistical analysis tools to analyse disc brake squeal.

Clinical significance of intramammary arterial calcifications in diabetic women

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Milošević Zorica

2004-01-01

Full Text Available Background. It is well known that intramammary arterial calcifications diagnosed by mammography as a part of generalized diabetic macroangiopathy may be an indirect sign of diabetes mellitus. Hence, the aim of this study was to determine the incidence of intramammary arterial calcifications, the patient’s age when the calcifications occur, as well as to observe the influence of diabetic polineuropathy, type, and the duration of diabetes on the onset of calcifications, in comparison with nondiabetic women. Methods. Mammographic findings of 113 diabetic female patients (21 with type 1 diabetes and 92 with type 2, as well as of 208 nondiabetic women (the control group were analyzed in the prospective study. The data about the type of diabetes, its duration, and polineuropathy were obtained using the questionnaire. Statistical differences were determined by Mann-Whitney test. Results. Intramammary arterial calcifications were identified in 33.3% of the women with type 1 diabetes, in 40.2% with type 2, and in 8.2% of the women from the control group, respectively. The differences comparing the women with type 1, as well as type 2 diabetes and the controls were statistically significant (p=0.0001. Women with intramammary arterial calcifications and type 1 diabetes were younger comparing to the control group (median age 52 years, comparing to 67 years of age, p=0.001, while there was no statistically significant difference in age between the women with calcifications and type 2 diabetes (61 years of age in relation to the control group (p=0.176. The incidence of polineuropathy in diabetic women was higher in the group with intramammary arterial calcifications (52.3% in comparison to the group without calcifications (26.1%, (p=0.005. The association between intramammary arterial calcifications and the duration of diabetes was not found. Conclusion. The obtained results supported the theory that intramammary arterial calcifications, detected by

Assessing compositional variability through graphical analysis and Bayesian statistical approaches: case studies on transgenic crops.

Science.gov (United States)

Harrigan, George G; Harrison, Jay M

2012-01-01

New transgenic (GM) crops are subjected to extensive safety assessments that include compositional comparisons with conventional counterparts as a cornerstone of the process. The influence of germplasm, location, environment, and agronomic treatments on compositional variability is, however, often obscured in these pair-wise comparisons. Furthermore, classical statistical significance testing can often provide an incomplete and over-simplified summary of highly responsive variables such as crop composition. In order to more clearly describe the influence of the numerous sources of compositional variation we present an introduction to two alternative but complementary approaches to data analysis and interpretation. These include i) exploratory data analysis (EDA) with its emphasis on visualization and graphics-based approaches and ii) Bayesian statistical methodology that provides easily interpretable and meaningful evaluations of data in terms of probability distributions. The EDA case-studies include analyses of herbicide-tolerant GM soybean and insect-protected GM maize and soybean. Bayesian approaches are presented in an analysis of herbicide-tolerant GM soybean. Advantages of these approaches over classical frequentist significance testing include the more direct interpretation of results in terms of probabilities pertaining to quantities of interest and no confusion over the application of corrections for multiple comparisons. It is concluded that a standardized framework for these methodologies could provide specific advantages through enhanced clarity of presentation and interpretation in comparative assessments of crop composition.

Statistics: a Bayesian perspective

National Research Council Canada - National Science Library

Berry, Donald A

1996-01-01

...: it is the only introductory textbook based on Bayesian ideas, it combines concepts and methods, it presents statistics as a means of integrating data into the significant process, it develops ideas...

To Identify the Important Soil Properties Affecting Dinoseb Adsorption with Statistical Analysis

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Yiqing Guan

2013-01-01

Full Text Available Investigating the influences of soil characteristic factors on dinoseb adsorption parameter with different statistical methods would be valuable to explicitly figure out the extent of these influences. The correlation coefficients and the direct, indirect effects of soil characteristic factors on dinoseb adsorption parameter were analyzed through bivariate correlation analysis, and path analysis. With stepwise regression analysis the factors which had little influence on the adsorption parameter were excluded. Results indicate that pH and CEC had moderate relationship and lower direct effect on dinoseb adsorption parameter due to the multicollinearity with other soil factors, and organic carbon and clay contents were found to be the most significant soil factors which affect the dinoseb adsorption process. A regression is thereby set up to explore the relationship between the dinoseb adsorption parameter and the two soil factors: the soil organic carbon and clay contents. A 92% of the variation of dinoseb sorption coefficient could be attributed to the variation of the soil organic carbon and clay contents.

Computational statistics and biometry: which discipline drives which?

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Edler, Lutz

2005-06-01

Full Text Available A biometrician's work is defined through the biological or medical problem and the mathematical and statistical methods needed for its solution. This requires in most instances statistical data analysis and the use of methods of computational statistics. At first, it seems quite obvious that the computational needs of the biometric problem determine what has to be developed by the discipline of computational statistics. However, viewing the development of biometry and computational statistics in Germany for the past decades in more details reveals an interesting interaction between the activities of the German Region of the International Biometric Society and groups engaged in computational statistics within Germany. Exact methods of statistical inference and permutation tests, simulations and the use of the Bootstrap, and interactive graphical statistical methods are examples of this fruitful reciprocal benefit. This contribution examines therefore relationships between the historical development of biometry and computational statistics in Germany using as sources of information contributions to the scientific literature, presentations and sessions at scientific conferences on biometry and on computational statistics which influenced the development of both disciplines and exhibits a reciprocal dependency. The annual workshops organized on the Reisensburg now for more than 30 years are recognized as an outstanding factor of this interrelationship. This work aims at the definition of the present status of computational statistics in the German Region of the International Biometric Society and intends to guide and to foster the discussion of the future development of this discipline among biometricians.

Influence of hearing age and understanding verbal instructions in children with cochlear implants

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Đoković Sanja

2013-01-01

Full Text Available Hearing age is defined as a period of using any amplification. Most researches indicate that hearing age influences the developmental rate of auditory and speech-language abilities in deaf children, especially when cochlear implantation was performed before the age of three. This research is aimed at analyzing the influence of hearing age on understanding verbal instructions in children with cochlear implants. The sample consists of 23 children with cochlear implants and 21 children with normal hearing, aged between 4 and 10. Hearing age of children with cochlear implants was between 2 and 7 years. Token Test with toys, adapted for children with hearing impairments, was used to analyze understanding verbal instructions. The results indicate that there are statistically significant differences between children with cochlear implants and children with normal hearing, aged between 4 and 7, on all subtests and the total score regardless of the hearing age (sub1 p<0.001, sub2 p<0.000, sub3 p<0.001, total score p<0.000. No statistically significant differences were determined on any of the subtests in children aged between 7.1 and 10, regardless of the hearing age. Comparative results analysis within the experimental group of children with different hearing age indicates that the difference in understanding verbal instructions between these two groups is not statistically significant.

Effect size and statistical power in the rodent fear conditioning literature - A systematic review.

Science.gov (United States)

Carneiro, Clarissa F D; Moulin, Thiago C; Macleod, Malcolm R; Amaral, Olavo B

2018-01-01

Proposals to increase research reproducibility frequently call for focusing on effect sizes instead of p values, as well as for increasing the statistical power of experiments. However, it is unclear to what extent these two concepts are indeed taken into account in basic biomedical science. To study this in a real-case scenario, we performed a systematic review of effect sizes and statistical power in studies on learning of rodent fear conditioning, a widely used behavioral task to evaluate memory. Our search criteria yielded 410 experiments comparing control and treated groups in 122 articles. Interventions had a mean effect size of 29.5%, and amnesia caused by memory-impairing interventions was nearly always partial. Mean statistical power to detect the average effect size observed in well-powered experiments with significant differences (37.2%) was 65%, and was lower among studies with non-significant results. Only one article reported a sample size calculation, and our estimated sample size to achieve 80% power considering typical effect sizes and variances (15 animals per group) was reached in only 12.2% of experiments. Actual effect sizes correlated with effect size inferences made by readers on the basis of textual descriptions of results only when findings were non-significant, and neither effect size nor power correlated with study quality indicators, number of citations or impact factor of the publishing journal. In summary, effect sizes and statistical power have a wide distribution in the rodent fear conditioning literature, but do not seem to have a large influence on how results are described or cited. Failure to take these concepts into consideration might limit attempts to improve reproducibility in this field of science.

Perceived Statistical Knowledge Level and Self-Reported Statistical Practice Among Academic Psychologists

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Laura Badenes-Ribera

2018-06-01

Full Text Available Introduction: Publications arguing against the null hypothesis significance testing (NHST procedure and in favor of good statistical practices have increased. The most frequently mentioned alternatives to NHST are effect size statistics (ES, confidence intervals (CIs, and meta-analyses. A recent survey conducted in Spain found that academic psychologists have poor knowledge about effect size statistics, confidence intervals, and graphic displays for meta-analyses, which might lead to a misinterpretation of the results. In addition, it also found that, although the use of ES is becoming generalized, the same thing is not true for CIs. Finally, academics with greater knowledge about ES statistics presented a profile closer to good statistical practice and research design. Our main purpose was to analyze the extension of these results to a different geographical area through a replication study.Methods: For this purpose, we elaborated an on-line survey that included the same items as the original research, and we asked academic psychologists to indicate their level of knowledge about ES, their CIs, and meta-analyses, and how they use them. The sample consisted of 159 Italian academic psychologists (54.09% women, mean age of 47.65 years. The mean number of years in the position of professor was 12.90 (SD = 10.21.Results: As in the original research, the results showed that, although the use of effect size estimates is becoming generalized, an under-reporting of CIs for ES persists. The most frequent ES statistics mentioned were Cohen's d and R2/η2, which can have outliers or show non-normality or violate statistical assumptions. In addition, academics showed poor knowledge about meta-analytic displays (e.g., forest plot and funnel plot and quality checklists for studies. Finally, academics with higher-level knowledge about ES statistics seem to have a profile closer to good statistical practices.Conclusions: Changing statistical practice is not

Dynamical significance of tides over the Bay of Bengal

Science.gov (United States)

Bhagawati, Chirantan; Pandey, Suchita; Dandapat, Sumit; Chakraborty, Arun

2018-06-01

Tides play a significant role in the ocean surface circulations and vertical mixing thereby influencing the Sea Surface Temperatures (SST) as well. This, in turn, plays an important role in the global circulation when used as a lower boundary condition in a global atmospheric general circulation model. Therefore in the present study, the dynamics of tides over the Bay of Bengal (BoB) is investigated through numerical simulations using a high resolution (1/12°) Regional Ocean Modeling System (ROMS). Based on statistical analysis it is observed that incorporation of explicit tidal forcing improves the model performance in simulating the basin averaged monthly surface circulation features by 64% compared to the simulation without tides. The model simulates also Mixed Layer Depth (MLD) and SST realistically. The energy exchange between tidal oscillations and eddies leads to redistribution of surface kinetic energy density with a net decrease of 0.012 J m-3 in the western Bay and a net increase of 0.007 J m-3 in the eastern Bay. The tidal forcing also affects the potential energy anomaly and vertical mixing thereby leading to a fall in monthly MLD over the BoB. The mixing due to tides leads to a subsequent reduction in monthly SST and a corresponding reduction in surface heat exchange. These results from the numerical simulation using ROMS reveal that tides have a significant influence over the air-sea heat exchange which is the most important parameter for prediction of Tropical Cyclone frequency and its future variability over the BoB.

The Influence of Experiential Marketing, Emotional Branding, Brand Trust Towards Brand Loyalty

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Retno Dewanti

2011-11-01

Full Text Available The restaurant business in jakarta showed rapidly increased. Marketing today as the compete of brand strategy and experiental marketing on the competitive situation. The Jun Jan Kitchen is a new restaurant specialized on Chinnese Food, urgent to know the brand loyalty. The Aim research is to measured the influence of Experiental marketing, emotional branding and brand trust towards brand loyalty. Research method used descriptif, data collecting technique with questioner and observation. Statistic tools using path analysis to looking for contribution level on each variabel towards other. Population this research is customer Jun Jan Kitchen. Sampling technique using accidental sampling. Amount of sample is 100 customers. Result of this research is experiental marketing giving the significant influence towards brand trust whereas Emotional branding giving the significant influence towards brand loyalty. 

Latinos in science: Identifying factors that influence the low percentage of Latino representation in the sciences

Science.gov (United States)

Miranda, Susan Jennifer

A mixed methods approach was used to identify factors that influence the underrepresentation of Latinos in the domain of science. The researcher investigated the role of family influences, academic preparation, and personal motivations to determine science-related career choices by Latinos. Binary logistic regression analyses were conducted using information from Latinos gathered from the National Education Longitudinal Study of 1988 (NELS: 88) administered by the National Center for Education Statistics. For the present study, data were analyzed using participants' responses as high school seniors, college students, and post-baccalaureates. Students responded to questions on school, work, parental academic influences, personal aspirations, and self-perception. To provide more insight into the experiences of Latinos in science and support the statistical analyses, nine students majoring in science in a private, urban university located in the northeastern part of the country were interviewed. Eleven variables related to parents' academic support and students' perceptions of parental support were taken together as predictors for two separate criteria from the survey. These results identified parents' level of education and the importance of academics to parents in their teen's college choice as significant predictors in determining college major in science. When the criterion was degree in science, the significant predictor was the frequency parents contacted high school as volunteers. Student interviews supported this information, demonstrating the importance of parental support in attaining a degree in science. Academic preparation was also analyzed. Students' reasons for taking science classes in high school was a significant predictor for science major; significant predictors for science degree were the emphasis placed on objectives in math and science classes and number of courses in biology and physics. Student interviews supported this information and

Understanding Statistics - Cancer Statistics

Science.gov (United States)

Annual reports of U.S. cancer statistics including new cases, deaths, trends, survival, prevalence, lifetime risk, and progress toward Healthy People targets, plus statistical summaries for a number of common cancer types.

Funding source and primary outcome changes in clinical trials registered on ClinicalTrials.gov are associated with the reporting of a statistically significant primary outcome: a cross-sectional study [v2; ref status: indexed, http://f1000r.es/5bj

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Sreeram V Ramagopalan

2015-04-01

Full Text Available Background: We and others have shown a significant proportion of interventional trials registered on ClinicalTrials.gov have their primary outcomes altered after the listed study start and completion dates. The objectives of this study were to investigate whether changes made to primary outcomes are associated with the likelihood of reporting a statistically significant primary outcome on ClinicalTrials.gov. Methods: A cross-sectional analysis of all interventional clinical trials registered on ClinicalTrials.gov as of 20 November 2014 was performed. The main outcome was any change made to the initially listed primary outcome and the time of the change in relation to the trial start and end date. Findings: 13,238 completed interventional trials were registered with ClinicalTrials.gov that also had study results posted on the website. 2555 (19.3% had one or more statistically significant primary outcomes. Statistical analysis showed that registration year, funding source and primary outcome change after trial completion were associated with reporting a statistically significant primary outcome. Conclusions: Funding source and primary outcome change after trial completion are associated with a statistically significant primary outcome report on clinicaltrials.gov.

A method for statistically comparing spatial distribution maps

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Reynolds Mary G

2009-01-01

Full Text Available Abstract Background Ecological niche modeling is a method for estimation of species distributions based on certain ecological parameters. Thus far, empirical determination of significant differences between independently generated distribution maps for a single species (maps which are created through equivalent processes, but with different ecological input parameters, has been challenging. Results We describe a method for comparing model outcomes, which allows a statistical evaluation of whether the strength of prediction and breadth of predicted areas is measurably different between projected distributions. To create ecological niche models for statistical comparison, we utilized GARP (Genetic Algorithm for Rule-Set Production software to generate ecological niche models of human monkeypox in Africa. We created several models, keeping constant the case location input records for each model but varying the ecological input data. In order to assess the relative importance of each ecological parameter included in the development of the individual predicted distributions, we performed pixel-to-pixel comparisons between model outcomes and calculated the mean difference in pixel scores. We used a two sample Student's t-test, (assuming as null hypothesis that both maps were identical to each other regardless of which input parameters were used to examine whether the mean difference in corresponding pixel scores from one map to another was greater than would be expected by chance alone. We also utilized weighted kappa statistics, frequency distributions, and percent difference to look at the disparities in pixel scores. Multiple independent statistical tests indicated precipitation as the single most important independent ecological parameter in the niche model for human monkeypox disease. Conclusion In addition to improving our understanding of the natural factors influencing the distribution of human monkeypox disease, such pixel-to-pixel comparison

Decomposable pseudodistances and applications in statistical estimation

Czech Academy of Sciences Publication Activity Database

Broniatowski, M.; Vajda, Igor

2012-01-01

Roč. 142, č. 9 (2012), s. 2574-2585 ISSN 0378-3758 Institutional research plan: CEZ:AV0Z10750506 Institutional support: RVO:67985556 Keywords : Parametric model * Pseudodistance * Influence function Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.713, year: 2012 http://library.utia.cas.cz/separaty/2012/SI/vajda-0436865.pdf

Correlation of RNA secondary structure statistics with thermodynamic stability and applications to folding.

Science.gov (United States)

Wu, Johnny C; Gardner, David P; Ozer, Stuart; Gutell, Robin R; Ren, Pengyu

2009-08-28

The accurate prediction of the secondary and tertiary structure of an RNA with different folding algorithms is dependent on several factors, including the energy functions. However, an RNA higher-order structure cannot be predicted accurately from its sequence based on a limited set of energy parameters. The inter- and intramolecular forces between this RNA and other small molecules and macromolecules, in addition to other factors in the cell such as pH, ionic strength, and temperature, influence the complex dynamics associated with transition of a single stranded RNA to its secondary and tertiary structure. Since all of the factors that affect the formation of an RNAs 3D structure cannot be determined experimentally, statistically derived potential energy has been used in the prediction of protein structure. In the current work, we evaluate the statistical free energy of various secondary structure motifs, including base-pair stacks, hairpin loops, and internal loops, using their statistical frequency obtained from the comparative analysis of more than 50,000 RNA sequences stored in the RNA Comparative Analysis Database (rCAD) at the Comparative RNA Web (CRW) Site. Statistical energy was computed from the structural statistics for several datasets. While the statistical energy for a base-pair stack correlates with experimentally derived free energy values, suggesting a Boltzmann-like distribution, variation is observed between different molecules and their location on the phylogenetic tree of life. Our statistical energy values calculated for several structural elements were utilized in the Mfold RNA-folding algorithm. The combined statistical energy values for base-pair stacks, hairpins and internal loop flanks result in a significant improvement in the accuracy of secondary structure prediction; the hairpin flanks contribute the most.

Statistical analysis and data management

International Nuclear Information System (INIS)

Anon.

1981-01-01

This report provides an overview of the history of the WIPP Biology Program. The recommendations of the American Institute of Biological Sciences (AIBS) for the WIPP biology program are summarized. The data sets available for statistical analyses and problems associated with these data sets are also summarized. Biological studies base maps are presented. A statistical model is presented to evaluate any correlation between climatological data and small mammal captures. No statistically significant relationship between variance in small mammal captures on Dr. Gennaro's 90m x 90m grid and precipitation records from the Duval Potash Mine were found

Model output statistics applied to wind power prediction

Energy Technology Data Exchange (ETDEWEB)

Joensen, A; Giebel, G; Landberg, L [Risoe National Lab., Roskilde (Denmark); Madsen, H; Nielsen, H A [The Technical Univ. of Denmark, Dept. of Mathematical Modelling, Lyngby (Denmark)

1999-03-01

Being able to predict the output of a wind farm online for a day or two in advance has significant advantages for utilities, such as better possibility to schedule fossil fuelled power plants and a better position on electricity spot markets. In this paper prediction methods based on Numerical Weather Prediction (NWP) models are considered. The spatial resolution used in NWP models implies that these predictions are not valid locally at a specific wind farm. Furthermore, due to the non-stationary nature and complexity of the processes in the atmosphere, and occasional changes of NWP models, the deviation between the predicted and the measured wind will be time dependent. If observational data is available, and if the deviation between the predictions and the observations exhibits systematic behavior, this should be corrected for; if statistical methods are used, this approaches is usually referred to as MOS (Model Output Statistics). The influence of atmospheric turbulence intensity, topography, prediction horizon length and auto-correlation of wind speed and power is considered, and to take the time-variations into account, adaptive estimation methods are applied. Three estimation techniques are considered and compared, Extended Kalman Filtering, recursive least squares and a new modified recursive least squares algorithm. (au) EU-JOULE-3. 11 refs.

Confounding and Statistical Significance of Indirect Effects: Childhood Adversity, Education, Smoking, and Anxious and Depressive Symptomatology

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Mashhood Ahmed Sheikh

2017-08-01

mediate the association between childhood adversity and ADS in adulthood. However, when education was excluded as a mediator-response confounding variable, the indirect effect of childhood adversity on ADS in adulthood was statistically significant (p < 0.05. This study shows that a careful inclusion of potential confounding variables is important when assessing mediation.

Statistical Dependence of Pipe Breaks on Explanatory Variables

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Patricia Gómez-Martínez

2017-02-01

Full Text Available Aging infrastructure is the main challenge currently faced by water suppliers. Estimation of assets lifetime requires reliable criteria to plan assets repair and renewal strategies. To do so, pipe break prediction is one of the most important inputs. This paper analyzes the statistical dependence of pipe breaks on explanatory variables, determining their optimal combination and quantifying their influence on failure prediction accuracy. A large set of registered data from Madrid water supply network, managed by Canal de Isabel II, has been filtered, classified and studied. Several statistical Bayesian models have been built and validated from the available information with a technique that combines reference periods of time as well as geographical location. Statistical models of increasing complexity are built from zero up to five explanatory variables following two approaches: a set of independent variables or a combination of two joint variables plus an additional number of independent variables. With the aim of finding the variable combination that provides the most accurate prediction, models are compared following an objective validation procedure based on the model skill to predict the number of pipe breaks in a large set of geographical locations. As expected, model performance improves as the number of explanatory variables increases. However, the rate of improvement is not constant. Performance metrics improve significantly up to three variables, but the tendency is softened for higher order models, especially in trunk mains where performance is reduced. Slight differences are found between trunk mains and distribution lines when selecting the most influent variables and models.

Influence of demographic and socioeconomic characteristics on the quality of life

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Grbić Gordana

2011-01-01

Full Text Available Introduction. The quality of life is a multidimensional concept, which is best expressed by the subjective well-being. Evaluation of the quality of life is the basis for measuring the well-being, and the determination of factors that determine the quality of life quality is the basis for its improvement Objective. To evaluate and assess the determinants of the perceived quality of life of group distinguishing features which characterize demographic and socioeconomic factors. Methods. This was a cross-sectional study of a representative sample of the population in Serbia aged over 20 years (9479 examinees. The quality of life was expressed by the perception of well-being (pleasure of life. Data on the examinees (demographic and socioeconomic characteristics were collected by using a questionnaire for adults of each household. To process, analyze and present the data, we used the methods of parametric descriptive statistics (mean value, standard deviation, coefficient of variation, variance analysis and factor analysis. Results. Although men evaluated the quality of life with a slightly higher grading, there was no statistically significant difference in the evaluation of the quality of life in relation to the examinee’s gender (p>0.005. Among the examinees there was a high statistically significant difference in grading the quality of life depending on age, level of education, marital status and type of job (p<0.001. In relation to the number of children, there was no statistically significant difference in he grading of the quality of life (p>0.005. Conclusion. The quality of life is influenced by numerous factors that characterize each person (demographic and socioeconomic characteristics of individual. Determining factors of the quality of life are numerous and diverse, and the manner and the strength of their influence are variable.

INFLUENCE OF FIRM SIZE ON ITS BUSINESS SUCCESS

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Maja Pervan

2012-12-01

Full Text Available A firm may use different methods and diverse (nonfinancial analysis/indicators in order to evaluate its business success. However, one of the most widely applied methods refers to financial analyses that use profitability ratios as the key measures of firm’s overall efficiency and performance. In this research we focused our attention on firm size and evaluated its influence on firm profitability. Other than by the size of a firm, a firm performance is affected by a variety of internal and external variables. Therefore, apart from mere investigating the relationship between firm size and performance, we also explored the impact of some other variables crucial in determining firm profitability. The analysis was conducted for the 2002-2010 period and the results revealed that firm size has a significant positive (although weak influence on firm profitability. Additionally, results showed that assets turnover and debt ratio also statistically significantly influence firms’ performance while current ratio didn’t prove to be an important explanatory variable of firms’ profitability.

Irrigated Area Maps and Statistics of India Using Remote Sensing and National Statistics

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Prasad S. Thenkabail

2009-04-01

with inadequate statistical analysis. Overall, the factors that influenced uncertainty in irrigated areas in remote sensing and national statistics were: (a inadequate accounting of irrigated areas, especially minor irrigation from groundwater, in the national statistics, (b definition issues involved in mapping using remote sensing as well as national statistics, (c difficulties in arriving at precise estimates of irrigated area fractions (IAFs using remote sensing, and (d imagery resolution in remote sensing. The study clearly established the existing uncertainties in irrigated area estimates and indicates that both remote sensing and national statistical approaches require further refinement. The need for accurate estimates of irrigated areas are crucial for water use assessments and food security studies and requires high emphasis.

Registered nurses' perceptions of rewarding and its significance.

Science.gov (United States)

Seitovirta, Jaana; Lehtimäki, Aku-Ville; Vehviläinen-Julkunen, Katri; Mitronen, Lasse; Kvist, Tarja

2017-11-07

To examine reward type preferences and their relationships with the significance of rewarding perceived by registered nurses in Finland. Previous studies have found relationships between nurses' rewarding and their motivation at work, job satisfaction and organisational commitment. Data were collected in a cross-sectional, descriptive, questionnaire survey from 402 registered nurses using the Registered Nurses' Perceptions of Rewarding Scale in 2015, and analysed with descriptive and multivariate statistical methods. Registered nurses assigned slightly higher values to several non-financial than to financial rewards. The non-financial reward types appreciation and feedback from work community, worktime arrangements, work content, and opportunity to develop, influence and participate were highly related to the significance of rewarding. We identified various rewards that registered nurses value, and indications that providing an appropriate array of rewards, particularly non-financial rewards, is a highly beneficial element of nursing management. It is important to understand the value of rewards for nursing management. Nurse managers should offer diverse rewards to their registered nurses to promote excellent performance and to help efforts to secure and maintain high-quality, safe patient care. The use of appropriate rewards is especially crucial to improving registered nurses' reward satisfaction and job satisfaction globally in the nursing profession. © 2017 John Wiley & Sons Ltd.

Is there any influence of breastfeeding on the cerebral blood flow? A review of 256 healthy newborns

Directory of Open Access Journals (Sweden)

Alexandra Maria Vieira Monteiro

2012-10-01

Full Text Available OBJECTIVE: To investigate whether breastfeeding influence the cerebral blood-flow velocity. MATERIALS AND METHODS: The present study included 256 healthy term neonates, all of them with appropriate weight for gestational age, 50.8% being female. Pulsatility index, resistance index and mean velocity were measured during breastfeeding or resting in the anterior cerebral artery, in the left middle cerebral artery, and in the right middle cerebral artery of the neonates between their first 10 and 48 hours of life. The data were analyzed by means of a paired t-test, Brieger's f-test for analysis of variance and linear regression, with p < 0.01 being accepted as statistically significant. RESULTS: Mean resistance index decreased as the mean velocity increased significantly during breastfeeding. Pulsatility index values decreased as much as the resistance index, but in the right middle cerebral artery it was not statistically significant. CONCLUSION: Breastfeeding influences the cerebral blood flow velocities.

Statistical analysis of aerosol species, trace gasses, and meteorology in Chicago.

Science.gov (United States)

Binaku, Katrina; O'Brien, Timothy; Schmeling, Martina; Fosco, Tinamarie

2013-09-01

Both canonical correlation analysis (CCA) and principal component analysis (PCA) were applied to atmospheric aerosol and trace gas concentrations and meteorological data collected in Chicago during the summer months of 2002, 2003, and 2004. Concentrations of ammonium, calcium, nitrate, sulfate, and oxalate particulate matter, as well as, meteorological parameters temperature, wind speed, wind direction, and humidity were subjected to CCA and PCA. Ozone and nitrogen oxide mixing ratios were also included in the data set. The purpose of statistical analysis was to determine the extent of existing linear relationship(s), or lack thereof, between meteorological parameters and pollutant concentrations in addition to reducing dimensionality of the original data to determine sources of pollutants. In CCA, the first three canonical variate pairs derived were statistically significant at the 0.05 level. Canonical correlation between the first canonical variate pair was 0.821, while correlations of the second and third canonical variate pairs were 0.562 and 0.461, respectively. The first canonical variate pair indicated that increasing temperatures resulted in high ozone mixing ratios, while the second canonical variate pair showed wind speed and humidity's influence on local ammonium concentrations. No new information was uncovered in the third variate pair. Canonical loadings were also interpreted for information regarding relationships between data sets. Four principal components (PCs), expressing 77.0 % of original data variance, were derived in PCA. Interpretation of PCs suggested significant production and/or transport of secondary aerosols in the region (PC1). Furthermore, photochemical production of ozone and wind speed's influence on pollutants were expressed (PC2) along with overall measure of local meteorology (PC3). In summary, CCA and PCA results combined were successful in uncovering linear relationships between meteorology and air pollutants in Chicago and

Influence of eye biometrics and corneal micro-structure on noncontact tonometry.

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Danilo A Jesus

Full Text Available Tonometry is widely used as the main screening tool supporting glaucoma diagnosis. Still, its accuracy could be improved if full knowledge about the variation of the corneal biomechanical properties was available. In this study, Optical Coherence Tomography (OCT speckle statistics are used to infer the organisation of the corneal micro-structure and hence, to analyse its influence on intraocular pressure (IOP measurements.Fifty-six subjects were recruited for this prospective study. Macro and micro-structural corneal parameters as well as subject age were considered. Macro-structural analysis included the parameters that are associated with the ocular anatomy, such as central corneal thickness (CCT, corneal radius, axial length, anterior chamber depth and white-to-white corneal diameter. Micro-structural parameters which included OCT speckle statistics were related to the internal organisation of the corneal tissue and its physiological changes during lifetime. The corneal speckle obtained from OCT was modelled with the Generalised Gamma (GG distribution that is characterised with a scale parameter and two shape parameters.In macro-structure analysis, only CCT showed a statistically significant correlation with IOP (R2 = 0.25, p<0.001. The scale parameter and the ratio of the shape parameters of GG distribution showed statistically significant correlation with IOP (R2 = 0.19, p<0.001 and R2 = 0.17, p<0.001, respectively. For the studied group, a weak, although significant correlation was found between age and IOP (R2 = 0.053, p = 0.04. Forward stepwise regression showed that CCT and the scale parameter of the Generalised Gamma distribution can be combined in a regression model (R2 = 0.39, p<0.001 to study the role of the corneal structure on IOP.We show, for the first time, that corneal micro-structure influences the IOP measurements obtained from noncontact tonometry. OCT speckle statistics can be employed to learn about the corneal micro

Influence of eye biometrics and corneal micro-structure on noncontact tonometry.

Science.gov (United States)

Jesus, Danilo A; Majewska, Małgorzata; Krzyżanowska-Berkowska, Patrycja; Iskander, D Robert

2017-01-01

Tonometry is widely used as the main screening tool supporting glaucoma diagnosis. Still, its accuracy could be improved if full knowledge about the variation of the corneal biomechanical properties was available. In this study, Optical Coherence Tomography (OCT) speckle statistics are used to infer the organisation of the corneal micro-structure and hence, to analyse its influence on intraocular pressure (IOP) measurements. Fifty-six subjects were recruited for this prospective study. Macro and micro-structural corneal parameters as well as subject age were considered. Macro-structural analysis included the parameters that are associated with the ocular anatomy, such as central corneal thickness (CCT), corneal radius, axial length, anterior chamber depth and white-to-white corneal diameter. Micro-structural parameters which included OCT speckle statistics were related to the internal organisation of the corneal tissue and its physiological changes during lifetime. The corneal speckle obtained from OCT was modelled with the Generalised Gamma (GG) distribution that is characterised with a scale parameter and two shape parameters. In macro-structure analysis, only CCT showed a statistically significant correlation with IOP (R2 = 0.25, p<0.001). The scale parameter and the ratio of the shape parameters of GG distribution showed statistically significant correlation with IOP (R2 = 0.19, p<0.001 and R2 = 0.17, p<0.001, respectively). For the studied group, a weak, although significant correlation was found between age and IOP (R2 = 0.053, p = 0.04). Forward stepwise regression showed that CCT and the scale parameter of the Generalised Gamma distribution can be combined in a regression model (R2 = 0.39, p<0.001) to study the role of the corneal structure on IOP. We show, for the first time, that corneal micro-structure influences the IOP measurements obtained from noncontact tonometry. OCT speckle statistics can be employed to learn about the corneal micro-structure and

Optimizing Groundwater Monitoring Networks Using Integrated Statistical and Geostatistical Approaches

Directory of Open Access Journals (Sweden)

Jay Krishna Thakur

2015-08-01

Full Text Available The aim of this work is to investigate new approaches using methods based on statistics and geo-statistics for spatio-temporal optimization of groundwater monitoring networks. The formulated and integrated methods were tested with the groundwater quality data set of Bitterfeld/Wolfen, Germany. Spatially, the monitoring network was optimized using geo-statistical methods. Temporal optimization of the monitoring network was carried out using Sen’s method (1968. For geostatistical network optimization, a geostatistical spatio-temporal algorithm was used to identify redundant wells in 2- and 2.5-D Quaternary and Tertiary aquifers. Influences of interpolation block width, dimension, contaminant association, groundwater flow direction and aquifer homogeneity on statistical and geostatistical methods for monitoring network optimization were analysed. The integrated approach shows 37% and 28% redundancies in the monitoring network in Quaternary aquifer and Tertiary aquifer respectively. The geostatistical method also recommends 41 and 22 new monitoring wells in the Quaternary and Tertiary aquifers respectively. In temporal optimization, an overall optimized sampling interval was recommended in terms of lower quartile (238 days, median quartile (317 days and upper quartile (401 days in the research area of Bitterfeld/Wolfen. Demonstrated methods for improving groundwater monitoring network can be used in real monitoring network optimization with due consideration given to influencing factors.

Factors influencing teamwork and collaboration within a tertiary medical center.

Science.gov (United States)

Chien, Shu Feng; Wan, Thomas Th; Chen, Yu-Chih

2012-04-26

To understand how work climate and related factors influence teamwork and collaboration in a large medical center. A survey of 3462 employees was conducted to generate responses to Sexton's Safety Attitudes Questionnaire (SAQ) to assess perceptions of work environment via a series of five-point, Likert-scaled questions. Path analysis was performed, using teamwork (TW) and collaboration (CO) as endogenous variables. The exogenous variables are effective communication (EC), safety culture (SC), job satisfaction (JS), work pressure (PR), and work climate (WC). The measurement instruments for the variables or summated subscales are presented. Reliability of each sub-scale are calculated. Alpha Cronbach coefficients are relatively strong: TW (0.81), CO (0.76), EC (0.70), SC (0.83), JS (0.91), WP (0.85), and WC (0.78). Confirmatory factor analysis was performed for each of these constructs. Path analysis enables to identify statistically significant predictors of two endogenous variables, teamwork and intra-organizational collaboration. Significant amounts of variance in perceived teamwork (R(2) = 0.59) and in collaboration (R(2) = 0.75) are accounted for by the predictor variables. In the initial model, safety culture is the most important predictor of perceived teamwork, with a β weight of 0.51, and work climate is the most significant predictor of collaboration, with a β weight of 0.84. After eliminating statistically insignificant causal paths and allowing correlated predictors1, the revised model shows that work climate is the only predictor positively influencing both teamwork (β = 0.26) and collaboration (β = 0.88). A relatively weak positive (β = 0.14) but statistically significant relationship exists between teamwork and collaboration when the effects of other predictors are simultaneously controlled. Hospital executives who are interested in improving collaboration should assess the work climate to ensure that employees are operating in a setting conducive

Factors influencing teamwork and collaboration within a tertiary medical center

Science.gov (United States)

Chien, Shu Feng; Wan, Thomas TH; Chen, Yu-Chih

2012-01-01

AIM: To understand how work climate and related factors influence teamwork and collaboration in a large medical center. METHODS: A survey of 3462 employees was conducted to generate responses to Sexton’s Safety Attitudes Questionnaire (SAQ) to assess perceptions of work environment via a series of five-point, Likert-scaled questions. Path analysis was performed, using teamwork (TW) and collaboration (CO) as endogenous variables. The exogenous variables are effective communication (EC), safety culture (SC), job satisfaction (JS), work pressure (PR), and work climate (WC). The measurement instruments for the variables or summated subscales are presented. Reliability of each sub-scale are calculated. Alpha Cronbach coefficients are relatively strong: TW (0.81), CO (0.76), EC (0.70), SC (0.83), JS (0.91), WP (0.85), and WC (0.78). Confirmatory factor analysis was performed for each of these constructs. RESULTS: Path analysis enables to identify statistically significant predictors of two endogenous variables, teamwork and intra-organizational collaboration. Significant amounts of variance in perceived teamwork (R2 = 0.59) and in collaboration (R2 = 0.75) are accounted for by the predictor variables. In the initial model, safety culture is the most important predictor of perceived teamwork, with a β weight of 0.51, and work climate is the most significant predictor of collaboration, with a β weight of 0.84. After eliminating statistically insignificant causal paths and allowing correlated predictors1, the revised model shows that work climate is the only predictor positively influencing both teamwork (β = 0.26) and collaboration (β = 0.88). A relatively weak positive (β = 0.14) but statistically significant relationship exists between teamwork and collaboration when the effects of other predictors are simultaneously controlled. CONCLUSION: Hospital executives who are interested in improving collaboration should assess the work climate to ensure that employees are

National Statistical Commission and Indian Official Statistics*

Indian Academy of Sciences (India)

IAS Admin

a good collection of official statistics of that time. With more .... statistical agencies and institutions to provide details of statistical activities .... ing several training programmes. .... ful completion of Indian Statistical Service examinations, the.

Statistical considerations on safety analysis

International Nuclear Information System (INIS)

Pal, L.; Makai, M.

2004-01-01

The authors have investigated the statistical methods applied to safety analysis of nuclear reactors and arrived at alarming conclusions: a series of calculations with the generally appreciated safety code ATHLET were carried out to ascertain the stability of the results against input uncertainties in a simple experimental situation. Scrutinizing those calculations, we came to the conclusion that the ATHLET results may exhibit chaotic behavior. A further conclusion is that the technological limits are incorrectly set when the output variables are correlated. Another formerly unnoticed conclusion of the previous ATHLET calculations that certain innocent looking parameters (like wall roughness factor, the number of bubbles per unit volume, the number of droplets per unit volume) can influence considerably such output parameters as water levels. The authors are concerned with the statistical foundation of present day safety analysis practices and can only hope that their own misjudgment will be dispelled. Until then, the authors suggest applying correct statistical methods in safety analysis even if it makes the analysis more expensive. It would be desirable to continue exploring the role of internal parameters (wall roughness factor, steam-water surface in thermal hydraulics codes, homogenization methods in neutronics codes) in system safety codes and to study their effects on the analysis. In the validation and verification process of a code one carries out a series of computations. The input data are not precisely determined because measured data have an error, calculated data are often obtained from a more or less accurate model. Some users of large codes are content with comparing the nominal output obtained from the nominal input, whereas all the possible inputs should be taken into account when judging safety. At the same time, any statement concerning safety must be aleatory, and its merit can be judged only when the probability is known with which the

Official Statistics and Statistics Education: Bridging the Gap

Directory of Open Access Journals (Sweden)

Gal Iddo

2017-03-01

Full Text Available This article aims to challenge official statistics providers and statistics educators to ponder on how to help non-specialist adult users of statistics develop those aspects of statistical literacy that pertain to official statistics. We first document the gap in the literature in terms of the conceptual basis and educational materials needed for such an undertaking. We then review skills and competencies that may help adults to make sense of statistical information in areas of importance to society. Based on this review, we identify six elements related to official statistics about which non-specialist adult users should possess knowledge in order to be considered literate in official statistics: (1 the system of official statistics and its work principles; (2 the nature of statistics about society; (3 indicators; (4 statistical techniques and big ideas; (5 research methods and data sources; and (6 awareness and skills for citizens’ access to statistical reports. Based on this ad hoc typology, we discuss directions that official statistics providers, in cooperation with statistics educators, could take in order to (1 advance the conceptualization of skills needed to understand official statistics, and (2 expand educational activities and services, specifically by developing a collaborative digital textbook and a modular online course, to improve public capacity for understanding of official statistics.

Influence of science and technology magnet middle schools on students' motivation and achievement in science

Science.gov (United States)

Allen, David

Some informal discussions among educators regarding motivation of students and academic performance have included the topic of magnet schools. The premise is that a focused theme, such as an aspect of science, positively affects student motivation and academic achievement. However, there is limited research involving magnet schools and their influence on student motivation and academic performance. This study provides empirical data for the discussion about magnet schools influence on motivation and academic ability. This study utilized path analysis in a structural equation modeling framework to simultaneously investigate the relationships between demographic exogenous independent variables, the independent variable of attending a science or technology magnet middle school, and the dependent variables of motivation to learn science and academic achievement in science. Due to the categorical nature of the variables, Bayesian statistical analysis was used to calculate the path coefficients and the standardized effects for each relationship in the model. The coefficients of determination were calculated to determine the amount of variance each path explained. Only five of 21 paths had statistical significance. Only one of the five statistically significant paths (Attended Magnet School to Motivation to Learn Science) explained a noteworthy amount (45.8%) of the variance.

Identifying clusters of active transportation using spatial scan statistics.

Science.gov (United States)

Huang, Lan; Stinchcomb, David G; Pickle, Linda W; Dill, Jennifer; Berrigan, David

2009-08-01

There is an intense interest in the possibility that neighborhood characteristics influence active transportation such as walking or biking. The purpose of this paper is to illustrate how a spatial cluster identification method can evaluate the geographic variation of active transportation and identify neighborhoods with unusually high/low levels of active transportation. Self-reported walking/biking prevalence, demographic characteristics, street connectivity variables, and neighborhood socioeconomic data were collected from respondents to the 2001 California Health Interview Survey (CHIS; N=10,688) in Los Angeles County (LAC) and San Diego County (SDC). Spatial scan statistics were used to identify clusters of high or low prevalence (with and without age-adjustment) and the quantity of time spent walking and biking. The data, a subset from the 2001 CHIS, were analyzed in 2007-2008. Geographic clusters of significantly high or low prevalence of walking and biking were detected in LAC and SDC. Structural variables such as street connectivity and shorter block lengths are consistently associated with higher levels of active transportation, but associations between active transportation and socioeconomic variables at the individual and neighborhood levels are mixed. Only one cluster with less time spent walking and biking among walkers/bikers was detected in LAC, and this was of borderline significance. Age-adjustment affects the clustering pattern of walking/biking prevalence in LAC, but not in SDC. The use of spatial scan statistics to identify significant clustering of health behaviors such as active transportation adds to the more traditional regression analysis that examines associations between behavior and environmental factors by identifying specific geographic areas with unusual levels of the behavior independent of predefined administrative units.

Mask effects on cosmological studies with weak-lensing peak statistics

International Nuclear Information System (INIS)

Liu, Xiangkun; Pan, Chuzhong; Fan, Zuhui; Wang, Qiao

2014-01-01

With numerical simulations, we analyze in detail how the bad data removal, i.e., the mask effect, can influence the peak statistics of the weak-lensing convergence field reconstructed from the shear measurement of background galaxies. It is found that high peak fractions are systematically enhanced because of the presence of masks; the larger the masked area is, the higher the enhancement is. In the case where the total masked area is about 13% of the survey area, the fraction of peaks with signal-to-noise ratio ν ≥ 3 is ∼11% of the total number of peaks, compared with ∼7% of the mask-free case in our considered cosmological model. This can have significant effects on cosmological studies with weak-lensing convergence peak statistics, inducing a large bias in the parameter constraints if the effects are not taken into account properly. Even for a survey area of 9 deg 2 , the bias in (Ω m , σ 8 ) is already intolerably large and close to 3σ. It is noted that most of the affected peaks are close to the masked regions. Therefore, excluding peaks in those regions in the peak statistics can reduce the bias effect but at the expense of losing usable survey areas. Further investigations find that the enhancement of the number of high peaks around the masked regions can be largely attributed to the smaller number of galaxies usable in the weak-lensing convergence reconstruction, leading to higher noise than that of the areas away from the masks. We thus develop a model in which we exclude only those very large masks with radius larger than 3' but keep all the other masked regions in peak counting statistics. For the remaining part, we treat the areas close to and away from the masked regions separately with different noise levels. It is shown that this two-noise-level model can account for the mask effect on peak statistics very well, and the bias in cosmological parameters is significantly reduced if this model is applied in the parameter fitting.

Effect size and statistical power in the rodent fear conditioning literature – A systematic review

Science.gov (United States)

Macleod, Malcolm R.

2018-01-01

Proposals to increase research reproducibility frequently call for focusing on effect sizes instead of p values, as well as for increasing the statistical power of experiments. However, it is unclear to what extent these two concepts are indeed taken into account in basic biomedical science. To study this in a real-case scenario, we performed a systematic review of effect sizes and statistical power in studies on learning of rodent fear conditioning, a widely used behavioral task to evaluate memory. Our search criteria yielded 410 experiments comparing control and treated groups in 122 articles. Interventions had a mean effect size of 29.5%, and amnesia caused by memory-impairing interventions was nearly always partial. Mean statistical power to detect the average effect size observed in well-powered experiments with significant differences (37.2%) was 65%, and was lower among studies with non-significant results. Only one article reported a sample size calculation, and our estimated sample size to achieve 80% power considering typical effect sizes and variances (15 animals per group) was reached in only 12.2% of experiments. Actual effect sizes correlated with effect size inferences made by readers on the basis of textual descriptions of results only when findings were non-significant, and neither effect size nor power correlated with study quality indicators, number of citations or impact factor of the publishing journal. In summary, effect sizes and statistical power have a wide distribution in the rodent fear conditioning literature, but do not seem to have a large influence on how results are described or cited. Failure to take these concepts into consideration might limit attempts to improve reproducibility in this field of science. PMID:29698451

Diffusing passive tracers in random incompressible flows: Statistical topography aspects

International Nuclear Information System (INIS)

Klyatskin, V.I.; Woyczynski, W.A.; Gurarie, D.

1996-01-01

The paper studies statistical characteristics of the passive tracer concentrations and of its spatial gradient, in random incompressible velocity fields from the viewpoint of statistical topography. The statistics of interest include mean values, probability distributions, as well as various functionals characterizing topographic features of tracers. The functional approach is used. We consider the influence of the mean flow (the linear shear flow) and the molecular diffusion coefficient on the statistics of the tracer. Most of our analysis is carried out in the framework of the delta-correlated (in time) approximation and conditions for its applicability are established. But we also consider the diffusion approximation scheme for finite correlation radius. The latter is applied to a diffusing passive tracer that undergoes sedimentation in a random velocity field

Aging Affects Adaptation to Sound-Level Statistics in Human Auditory Cortex.

Science.gov (United States)

Herrmann, Björn; Maess, Burkhard; Johnsrude, Ingrid S

2018-02-21

Optimal perception requires efficient and adaptive neural processing of sensory input. Neurons in nonhuman mammals adapt to the statistical properties of acoustic feature distributions such that they become sensitive to sounds that are most likely to occur in the environment. However, whether human auditory responses adapt to stimulus statistical distributions and how aging affects adaptation to stimulus statistics is unknown. We used MEG to study how exposure to different distributions of sound levels affects adaptation in auditory cortex of younger (mean: 25 years; n = 19) and older (mean: 64 years; n = 20) adults (male and female). Participants passively listened to two sound-level distributions with different modes (either 15 or 45 dB sensation level). In a control block with long interstimulus intervals, allowing neural populations to recover from adaptation, neural response magnitudes were similar between younger and older adults. Critically, both age groups demonstrated adaptation to sound-level stimulus statistics, but adaptation was altered for older compared with younger people: in the older group, neural responses continued to be sensitive to sound level under conditions in which responses were fully adapted in the younger group. The lack of full adaptation to the statistics of the sensory environment may be a physiological mechanism underlying the known difficulty that older adults have with filtering out irrelevant sensory information. SIGNIFICANCE STATEMENT Behavior requires efficient processing of acoustic stimulation. Animal work suggests that neurons accomplish efficient processing by adjusting their response sensitivity depending on statistical properties of the acoustic environment. Little is known about the extent to which this adaptation to stimulus statistics generalizes to humans, particularly to older humans. We used MEG to investigate how aging influences adaptation to sound-level statistics. Listeners were presented with sounds drawn from

Psychosocial factors for influencing healthy aging in adults in Korea.

Science.gov (United States)

Han, KyungHun; Lee, YunJung; Gu, JaSung; Oh, Hee; Han, JongHee; Kim, KwuyBun

2015-03-07

Healthy aging includes physical, psychological, social, and spiritual well-being in later years. The purpose of this study is to identify the psychosocial factors influencing healthy aging and examining their socio-demographic characteristics. Perceived health status, depression, self-esteem, self-achievement, ego-integrity, participation in leisure activities, and loneliness were identified as influential factors in healthy aging. 171 Korean adults aged between 45 and 77 years-old participated in the study. Self-reporting questionnaires were used, followed by descriptive statistics and multiple regressions as inferential statistical analyses. There were significant differences between participants' general characteristics: age, education, religion, housing, hobby, and economic status. The factors related to healthy aging had positive correlation with perceived health status, self-esteem, self-achievements, and leisure activities, and negative correlation with depression and loneliness. The factors influencing healthy aging were depression, leisure activities, perceived health status, ego integrity, and self-achievements. These factors were able to explain 51.9%. According to the results, depression is the factor with the greatest influence on healthy aging. Perceived health status, ego integrity, self-achievement, self-esteem, participation of leisure activities were also influential on healthy aging as beneficial factors.

A tilting approach to ranking influence

KAUST Repository

Genton, Marc G.; Hall, Peter

2014-01-01

We suggest a new approach, which is applicable for general statistics computed from random samples of univariate or vector-valued or functional data, to assessing the influence that individual data have on the value of a statistic, and to ranking

Genetic diversity in Capsicum baccatum is significantly influenced by its ecogeographical distribution

Science.gov (United States)

2012-01-01

Background The exotic pepper species Capsicum baccatum, also known as the aji or Peruvian hot pepper, is comprised of wild and domesticated botanical forms. The species is a valuable source of new genes useful for improving fruit quality and disease resistance in C. annuum sweet bell and hot chile pepper. However, relatively little research has been conducted to characterize the species, thus limiting its utilization. The structure of genetic diversity in a plant germplasm collection is significantly influenced by its ecogeographical distribution. Together with DNA fingerprints derived from AFLP markers, we evaluated variation in fruit and plant morphology of plants collected across the species native range in South America and evaluated these characters in combination with the unique geography, climate and ecology at different sites where plants originated. Results The present study mapped the ecogeographic distribution, analyzed the spatial genetic structure, and assessed the relationship between the spatial genetic pattern and the variation of morphological traits in a diverse C. baccatum germplasm collection spanning the species distribution. A combined diversity analysis was carried out on the USDA-ARS C. baccatum germplasm collection using data from GIS, morphological traits and AFLP markers. The results demonstrate that the C. baccatum collection covers wide geographic areas and is adapted to divergent ecological conditions in South America ranging from cool Andean highland to Amazonia rainforest. A high level of morphological diversity was evident in the collection, with fruit weight the leading variable. The fruit weight distribution pattern was compatible to AFLP-based clustering analysis for the collection. A significant spatial structure was observed in the C. baccatum gene pool. Division of the domesticated germplasm into two major regional groups (Western and Eastern) was further supported by the pattern of spatial population structure. Conclusions

Development of free statistical software enabling researchers to calculate confidence levels, clinical significance curves and risk-benefit contours

International Nuclear Information System (INIS)

Shakespeare, T.P.; Mukherjee, R.K.; Gebski, V.J.

2003-01-01

Confidence levels, clinical significance curves, and risk-benefit contours are tools improving analysis of clinical studies and minimizing misinterpretation of published results, however no software has been available for their calculation. The objective was to develop software to help clinicians utilize these tools. Excel 2000 spreadsheets were designed using only built-in functions, without macros. The workbook was protected and encrypted so that users can modify only input cells. The workbook has 4 spreadsheets for use in studies comparing two patient groups. Sheet 1 comprises instructions and graphic examples for use. Sheet 2 allows the user to input the main study results (e.g. survival rates) into a 2-by-2 table. Confidence intervals (95%), p-value and the confidence level for Treatment A being better than Treatment B are automatically generated. An additional input cell allows the user to determine the confidence associated with a specified level of benefit. For example if the user wishes to know the confidence that Treatment A is at least 10% better than B, 10% is entered. Sheet 2 automatically displays clinical significance curves, graphically illustrating confidence levels for all possible benefits of one treatment over the other. Sheet 3 allows input of toxicity data, and calculates the confidence that one treatment is more toxic than the other. It also determines the confidence that the relative toxicity of the most effective arm does not exceed user-defined tolerability. Sheet 4 automatically calculates risk-benefit contours, displaying the confidence associated with a specified scenario of minimum benefit and maximum risk of one treatment arm over the other. The spreadsheet is freely downloadable at www.ontumor.com/professional/statistics.htm A simple, self-explanatory, freely available spreadsheet calculator was developed using Excel 2000. The incorporated decision-making tools can be used for data analysis and improve the reporting of results of any

Influence of shelf life on the setting time of type IV gypsum

Science.gov (United States)

Hapsari, M. L.; Irawan, B.; Damiyanti, M.

2017-08-01

Although expired materials can exhibit a deterioration in their properties, expired type IV gypsum can still be found on the market. In order to evaluate the influence of the shelf life on its setting time, two groups of type IV gypsum (GC Fuji rock EP) with different expiration dates were used in this research. The setting time tests were done in a mold using a Vicat Needle apparatus. The results of the statistical analysis showed a significant difference (pshelf life did influence the setting time of the type IV gypsum.

Influences of credibility of testimony and strength of statistical evidence on children’s and adolescents’ reasoning

OpenAIRE

Kail, Robert V.

2013-01-01

According to dual-process models that include analytic and heuristic modes of processing, analytic processing is often expected to become more common with development. Consistent with this view, on reasoning problems, adolescents are more likely than children to select alternatives that are backed by statistical evidence. It is shown here that this pattern depends on the quality of the statistical evidence and the quality of the testimonial that is the typical alternative to statistical evide...

Methodological Problems Of Statistical Study Of Regional Tourism And Tourist Expenditure

Directory of Open Access Journals (Sweden)

Anton Olegovich Ovcharov

2015-03-01

Full Text Available The aim of the work is the analysis of the problems of regional tourism statistics. The subject of the research is the tourism expenditure, the specificity of their recording and modeling. The methods of statistical observation and factor analysis are used. The article shows the features and directions of statistical methodology of tourism. A brief review of international publications on statistical studies of tourist expenditure is made. It summarizes the data from different statistical forms and shows the positive and negative trends in the development of tourism in Russia. It is concluded that the tourist industry in Russia is focused on outbound tourism rather than on inbound or internal. The features of statistical accounting and statistical analysis of tourism expenditure in Russian and international statistics are described. To assess the level of development of regional tourism the necessity of use the coefficient of efficiency of tourism. The reasons of the prevalence of imports over exports of tourism services are revealed using the data of the balance of payments. This is due to the raw material orientation of Russian exports and low specific weight of the account “Services” in the structure of the balance of payments. The additive model is also proposed in the paper. It describes the influence of three factors on the changes in tourist expenditure. These factors are the number of trips, the cost of a trip and structural changes in destinations and travel purposes. On the basis of the data from 2012–2013 we estimate the force and the direction of the influence of each factor. Testing of the model showed that the increase in tourism exports caused by the combined positive impact of all three factors, chief of which is the growing number of foreigners who visited Russia during the concerned period.

Review of the Statistical Techniques in Medical Sciences | Okeh ...

African Journals Online (AJOL)

... medical researcher in selecting the appropriate statistical techniques. Of course, all statistical techniques have certain underlying assumptions, which must be checked before the technique is applied. Keywords: Variable, Prospective Studies, Retrospective Studies, Statistical significance. Bio-Research Vol. 6 (1) 2008: pp.

Selection of the Maximum Spatial Cluster Size of the Spatial Scan Statistic by Using the Maximum Clustering Set-Proportion Statistic.

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Ma, Yue; Yin, Fei; Zhang, Tao; Zhou, Xiaohua Andrew; Li, Xiaosong

2016-01-01

Spatial scan statistics are widely used in various fields. The performance of these statistics is influenced by parameters, such as maximum spatial cluster size, and can be improved by parameter selection using performance measures. Current performance measures are based on the presence of clusters and are thus inapplicable to data sets without known clusters. In this work, we propose a novel overall performance measure called maximum clustering set-proportion (MCS-P), which is based on the likelihood of the union of detected clusters and the applied dataset. MCS-P was compared with existing performance measures in a simulation study to select the maximum spatial cluster size. Results of other performance measures, such as sensitivity and misclassification, suggest that the spatial scan statistic achieves accurate results in most scenarios with the maximum spatial cluster sizes selected using MCS-P. Given that previously known clusters are not required in the proposed strategy, selection of the optimal maximum cluster size with MCS-P can improve the performance of the scan statistic in applications without identified clusters.

Spectral and cross-spectral analysis of uneven time series with the smoothed Lomb-Scargle periodogram and Monte Carlo evaluation of statistical significance

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Pardo-Igúzquiza, Eulogio; Rodríguez-Tovar, Francisco J.

2012-12-01

Many spectral analysis techniques have been designed assuming sequences taken with a constant sampling interval. However, there are empirical time series in the geosciences (sediment cores, fossil abundance data, isotope analysis, …) that do not follow regular sampling because of missing data, gapped data, random sampling or incomplete sequences, among other reasons. In general, interpolating an uneven series in order to obtain a succession with a constant sampling interval alters the spectral content of the series. In such cases it is preferable to follow an approach that works with the uneven data directly, avoiding the need for an explicit interpolation step. The Lomb-Scargle periodogram is a popular choice in such circumstances, as there are programs available in the public domain for its computation. One new computer program for spectral analysis improves the standard Lomb-Scargle periodogram approach in two ways: (1) It explicitly adjusts the statistical significance to any bias introduced by variance reduction smoothing, and (2) it uses a permutation test to evaluate confidence levels, which is better suited than parametric methods when neighbouring frequencies are highly correlated. Another novel program for cross-spectral analysis offers the advantage of estimating the Lomb-Scargle cross-periodogram of two uneven time series defined on the same interval, and it evaluates the confidence levels of the estimated cross-spectra by a non-parametric computer intensive permutation test. Thus, the cross-spectrum, the squared coherence spectrum, the phase spectrum, and the Monte Carlo statistical significance of the cross-spectrum and the squared-coherence spectrum can be obtained. Both of the programs are written in ANSI Fortran 77, in view of its simplicity and compatibility. The program code is of public domain, provided on the website of the journal (http://www.iamg.org/index.php/publisher/articleview/frmArticleID/112/). Different examples (with simulated and

Emancipation through interaction--how eugenics and statistics converged and diverged.

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Louçã, Francisco

2009-01-01

The paper discusses the scope and influence of eugenics in defining the scientific programme of statistics and the impact of the evolution of biology on social scientists. It argues that eugenics was instrumental in providing a bridge between sciences, and therefore created both the impulse and the institutions necessary for the birth of modern statistics in its applications first to biology and then to the social sciences. Looking at the question from the point of view of the history of statistics and the social sciences, and mostly concentrating on evidence from the British debates, the paper discusses how these disciplines became emancipated from eugenics precisely because of the inspiration of biology. It also relates how social scientists were fascinated and perplexed by the innovations taking place in statistical theory and practice.

Sex differences in discriminative power of volleyball game-related statistics.

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João, Paulo Vicente; Leite, Nuno; Mesquita, Isabel; Sampaio, Jaime

2010-12-01

To identify sex differences in volleyball game-related statistics, the game-related statistics of several World Championships in 2007 (N=132) were analyzed using the software VIS from the International Volleyball Federation. Discriminant analysis was used to identify the game-related statistics which better discriminated performances by sex. Analysis yielded an emphasis on fault serves (SC = -.40), shot spikes (SC = .40), and reception digs (SC = .31). Specific robust numbers represent that considerable variability was evident in the game-related statistics profile, as men's volleyball games were better associated with terminal actions (errors of service), and women's volleyball games were characterized by continuous actions (in defense and attack). These differences may be related to the anthropometric and physiological differences between women and men and their influence on performance profiles.

How do characteristics of donors and their children influence volume and composition of banked milk?

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Pasqua Anna Quitadamo

2018-03-01

Full Text Available When own mother’s milk is not available, donor human milk (DHM is the first choice in preterm infant feeding. Although worldwide strong efforts have been made to implement human milk (HM donation, there is currently little available research on donors characteristics and their influence on volume and composition of DHM. The present study aimed to evaluate the relationship between social-demographic variables of donating mothers (age, residence, job, number of children, as well as gestational age and birth weight of their babies, and volume and composition of donated HM.The analysis of data revealed a statistically significant impact of maternal age and profession, as well as babies’ birth weight and donation duration, on the volume of milk donation, but no effect of donor’s place of residence. Gestational age also had an effect on the volume of milk donation, but the effect was not statistically significant (p-value on the verge of significance.Regarding milk composition, gestational age < 29 weeks, low birth weight and overall donation period were statistically correlated to higher protein content. Statistical analysis of other DHM components did not result significant except for carbohydrates, being their content inversely associated with birth weight, with p-value at the margin of significance.

“Mind the Gap” in Reporting the Outdated Statistics

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Babak Moazen

2014-10-01

Full Text Available Close cooperation between researchers and policy-makers to find the specific health needs of communities, would lead to taking evidence-based decisions in addressing communities’ health problems. Publication errors, like reporting outdated statistics are among the key factors that influence effectiveness of such decisions.

Improved statistical power with a sparse shape model in detecting an aging effect in the hippocampus and amygdala

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Chung, Moo K.; Kim, Seung-Goo; Schaefer, Stacey M.; van Reekum, Carien M.; Peschke-Schmitz, Lara; Sutterer, Matthew J.; Davidson, Richard J.

2014-03-01

The sparse regression framework has been widely used in medical image processing and analysis. However, it has been rarely used in anatomical studies. We present a sparse shape modeling framework using the Laplace- Beltrami (LB) eigenfunctions of the underlying shape and show its improvement of statistical power. Tradition- ally, the LB-eigenfunctions are used as a basis for intrinsically representing surface shapes as a form of Fourier descriptors. To reduce high frequency noise, only the first few terms are used in the expansion and higher frequency terms are simply thrown away. However, some lower frequency terms may not necessarily contribute significantly in reconstructing the surfaces. Motivated by this idea, we present a LB-based method to filter out only the significant eigenfunctions by imposing a sparse penalty. For dense anatomical data such as deformation fields on a surface mesh, the sparse regression behaves like a smoothing process, which will reduce the error of incorrectly detecting false negatives. Hence the statistical power improves. The sparse shape model is then applied in investigating the influence of age on amygdala and hippocampus shapes in the normal population. The advantage of the LB sparse framework is demonstrated by showing the increased statistical power.

Statistical mechanics and the description of the early universe I

DEFF Research Database (Denmark)

Pessah, Martin Elias; F. Torres, Diego; Vucetich, H.

2001-01-01

We analyze how the thermal history of the universe is influenced by the statistical description, assuming a deviation from the usual Bose-Einstein, Fermi-Dirac and Boltzmann-Gibbs distribution functions. These deviations represent the possible appearance of non-extensive effects related with the ......We analyze how the thermal history of the universe is influenced by the statistical description, assuming a deviation from the usual Bose-Einstein, Fermi-Dirac and Boltzmann-Gibbs distribution functions. These deviations represent the possible appearance of non-extensive effects related...... and to place limits to the range of its validity. The corrections obtained will change with temperature, and consequently, the bounds on the possible amount of non-extensivity will also change with time. We generalize results which can be used in other contexts as well, as the Boltzmann equation and the Saha...

Statistical thermodynamics

International Nuclear Information System (INIS)

Lim, Gyeong Hui

2008-03-01

This book consists of 15 chapters, which are basic conception and meaning of statistical thermodynamics, Maxwell-Boltzmann's statistics, ensemble, thermodynamics function and fluctuation, statistical dynamics with independent particle system, ideal molecular system, chemical equilibrium and chemical reaction rate in ideal gas mixture, classical statistical thermodynamics, ideal lattice model, lattice statistics and nonideal lattice model, imperfect gas theory on liquid, theory on solution, statistical thermodynamics of interface, statistical thermodynamics of a high molecule system and quantum statistics

Emergency department crowding: factors influencing flow.

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Arkun, Alp; Briggs, William M; Patel, Sweha; Datillo, Paris A; Bove, Joseph; Birkhahn, Robert H

2010-02-01

THE OBJECTIVE OF THIS STUDY WAS TO EVALUATE THOSE FACTORS, BOTH INTRINSIC AND EXTRINSIC TO THE EMERGENCY DEPARTMENT (ED) THAT INFLUENCE TWO SPECIFIC COMPONENTS OF THROUGHPUT: "door-to-doctor" time and dwell time. We used a prospective observational study design to determine the variables that played a significant role in determining ED flow. All adult patients seen or waiting to be seen in the ED were observed at 8pm (Monday-Friday) during a three-month period. Variables measured included daily ED volume, patient acuity, staffing, ED occupancy, daily admissions, ED boarder volume, hospital volume, and intensive care unit volume. Both log-rank tests and time-to-wait (survival) proportional-hazard regression models were fitted to determine which variables were most significant in predicting "door-to-doctor" and dwell times, with full account of the censoring for some patients. We captured 1,543 patients during our study period, representing 27% of total daily volume. The ED operated at an average of 85% capacity (61-102%) with an average of 27% boarding. Median "door-to-doctor" time was 1.8 hours, with the biggest influence being triage category, day of the week, and ED occupancy. Median dwell time was 5.5 hours with similar variable influences. The largest contributors to decreased patient flow through the ED at our institution were triage category, ED occupancy, and day of the week. Although the statistically significant factors influencing patient throughput at our institution involve problems with inflow, an increase in ED occupancy could be due to substantial outflow obstruction and may indicate the necessity for increased capacity both within the ED and hospital.

Factors that influence the urodynamic results of botulinum toxin in the treatment of neurogenic hyperactivity.

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Gutiérrez-Martín, P; Vírseda-Chamorro, M; Salinas Casado, J; Gómez-Rodríguez, A; Esteban-Fuertes, M

2015-05-01

To determine the urodynamic efficacy and factors that influence the urodynamic results of treatment of neurogenic detrusor hyperactivity with intradetrusor injection of botulinum toxin type A (BTX-A) in patients with spinal cord injury (SCI). A retrospective study was conducted with a cohort of 70 patients composed of 40 men and 30 women with stable SCI (mean age, 39 ± 13.3 years) who underwent an intradetrusor injection of 300 IUs of BTX-A. A urodynamic study was conducted prior to the injection and 6 ± 4.3 months after the treatment. New urodynamic studies were subsequently performed up to an interval of 16 ± 12.2 months. The BTX-A significantly increased (p bladder capacity, the bladder volume of the first involuntary contraction of the detrusor and the postvoid residue. We observed a decrease that tended towards statistical significance (p bladder accommodation nor the urethral resistance index (bladder outlet obstruction index) varied significantly. The increase in vesical capacity was maintained in 50% of the sample for more than 32 months. Age, sex, anticholinergic treatment and lesion age showed no influence in terms of the increase in bladder capacity. The indwelling urinary catheter (IUC) was the only statistically significant negative factor. The urodynamic effect of BTX-A is maintained for a considerable time interval. The IUC negatively influences the result of the treatment. Copyright © 2014 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

The Statistical Modeling of the Trends Concerning the Romanian Population

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Gabriela OPAIT

2014-11-01

Full Text Available This paper reflects the statistical modeling concerning the resident population in Romania, respectively the total of the romanian population, through by means of the „Least Squares Method”. Any country it develops by increasing of the population, respectively of the workforce, which is a factor of influence for the growth of the Gross Domestic Product (G.D.P.. The „Least Squares Method” represents a statistical technique for to determine the trend line of the best fit concerning a model.

[Statistics for statistics?--Thoughts about psychological tools].

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Berger, Uwe; Stöbel-Richter, Yve

2007-12-01

Statistical methods take a prominent place among psychologists' educational programs. Being known as difficult to understand and heavy to learn, students fear of these contents. Those, who do not aspire after a research carrier at the university, will forget the drilled contents fast. Furthermore, because it does not apply for the work with patients and other target groups at a first glance, the methodological education as a whole was often questioned. For many psychological practitioners the statistical education makes only sense by enforcing respect against other professions, namely physicians. For the own business, statistics is rarely taken seriously as a professional tool. The reason seems to be clear: Statistics treats numbers, while psychotherapy treats subjects. So, does statistics ends in itself? With this article, we try to answer the question, if and how statistical methods were represented within the psychotherapeutical and psychological research. Therefore, we analyzed 46 Originals of a complete volume of the journal Psychotherapy, Psychosomatics, Psychological Medicine (PPmP). Within the volume, 28 different analyse methods were applied, from which 89 per cent were directly based upon statistics. To be able to write and critically read Originals as a backbone of research, presumes a high degree of statistical education. To ignore statistics means to ignore research and at least to reveal the own professional work to arbitrariness.

INFLUENCE OF DIFFERENT SOURCES OF WATER FOR IRRIGATION ON PEPPER (Capsicum annuum L. YIELD IN GLASSHOUSE CONDITIONS

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Jasna Šoštarić

2002-06-01

Full Text Available The aim of this paper was to determine the influence of different sources of water used for irrigation on the yield of pepper hybrids Cecil F1 and Bianca F1 in the early glasshouse production for the period 1998 - 2000 in the controlled glasshouse conditions in «D.G. – PROMET», Magadenovac, Croatia. Lagoon water and well water were two main sources of water used for irrigation in this experiment. Drip irrigation system was applied for pepper production. In comparison to lagoon water, chemical analyses of well water have shown increased values of the following elements: EC, sodium, potassium, calcium, chlorine, magnesium, bicarbonate, sulphate, iron and boron. Temperature of well water was lower than the allowed minimum and therefore had direct influence on the yield decrease. Consequently, areas which have been irrigated by well water have had problems with accumulation of slime and blocking of sprinklers, disturbed soil structure, fruit deformation and decreased crop yield. Statistical data analysis was conducted by the method of covariation three factorial trial (ABC with three repetitions for each treatment. The trial showed absolute difference regarding water efficiency of irrigation water from two sources, which has also been statistically determined (P<0,05. Furthermore, statistically justified difference in the average weight of the fruit of each investigated pepper hybrid (P<0,05 has been proven. Codependence of «water for irrigation» (A and «pepper hybrid» (B, i.e. (AB is statistically significant as well, and justified at the P<0,05 limit. This means that both pepper hybrids (Cecil F1 i Bianca F1 reacted differently to lagoon water and well water. Factor «year» (C has not proven to be statistically justified, and therefore does not have any significant influence on the crop yield due to controlled conditions in the glasshouse.

Innovations in Statistical Observations of Consumer Prices

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Olga Stepanovna Oleynik

2016-10-01

Full Text Available This article analyzes the innovative changes in the methodology of statistical surveys of consumer prices. These changes are reflected in the “Official statistical methodology for the organization of statistical observation of consumer prices for goods and services and the calculation of the consumer price index”, approved by order of the Federal State Statistics Service of December 30, 2014 no. 734. The essence of innovation is the use of mathematical methods in determining the range of studies objects of trade and services, in calculating the sufficient observable price quotes based on price dispersion, the proportion of the observed product (service, a representative of consumer spending, as well as the indicator of the complexity of price registration. The authors analyzed the mathematical calculations of the required number of quotations for observation in the Volgograd region in 2016, the results of calculations are compared with the number of quotes included in the monitoring. The authors believe that the implementation of these mathematical models allowed to substantially reduce the influence of the subjective factor in the organization of monitoring of consumer prices, and therefore to increase the objectivity of the resulting statistics on consumer prices and inflation. At the same time, the proposed methodology needs further improvement in terms of payment for goods, products (services by representatives having a minor share in consumer expenditure.

Extreme event statistics in a drifting Markov chain

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Kindermann, Farina; Hohmann, Michael; Lausch, Tobias; Mayer, Daniel; Schmidt, Felix; Widera, Artur

2017-07-01

We analyze extreme event statistics of experimentally realized Markov chains with various drifts. Our Markov chains are individual trajectories of a single atom diffusing in a one-dimensional periodic potential. Based on more than 500 individual atomic traces we verify the applicability of the Sparre Andersen theorem to our system despite the presence of a drift. We present detailed analysis of four different rare-event statistics for our system: the distributions of extreme values, of record values, of extreme value occurrence in the chain, and of the number of records in the chain. We observe that, for our data, the shape of the extreme event distributions is dominated by the underlying exponential distance distribution extracted from the atomic traces. Furthermore, we find that even small drifts influence the statistics of extreme events and record values, which is supported by numerical simulations, and we identify cases in which the drift can be determined without information about the underlying random variable distributions. Our results facilitate the use of extreme event statistics as a signal for small drifts in correlated trajectories.

The Influence of Industry Characteristics and Dynamic Capabilities on Firms’ Profitability

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Maja Pervan

2017-12-01

Full Text Available The aim of this research was to explore one of the most intriguing dimensions of every firm’s business—its performance. Aside from analysing the influence of industry’s characteristics on the firm’s performance, the authors addressed the characteristics of dynamic capabilities and their role in contribution to the firm’s ultimate success. The analysis was conducted on a sample of 118 small Croatian manufacturing companies. The application of the Structural Equation Modelling (SEM approach revealed a statistically significant influence of both the industry’s characteristics (represented by Porter’s five forces framework and dynamic capabilities (based on Teece’s theory on the firm’s performance, where the influence of dynamic capabilities is proven to be larger than that of the industry.

Prognostic significance of macrophage invasion in hilar cholangiocarcinoma

International Nuclear Information System (INIS)

Atanasov, Georgi; Hau, Hans-Michael; Dietel, Corinna; Benzing, Christian; Krenzien, Felix; Brandl, Andreas; Wiltberger, Georg; Matia, Ivan; Prager, Isabel; Schierle, Katrin; Robson, Simon C.; Reutzel-Selke, Anja; Pratschke, Johann; Schmelzle, Moritz; Jonas, Sven

2015-01-01

Tumor-associated macrophages (TAMs) promote tumor progression and have an effect on survival in human cancer. However, little is known regarding their influence on tumor progression and prognosis in human hilar cholangiocarcinoma. We analyzed surgically resected tumor specimens of hilar cholangiocarcinoma (n = 47) for distribution and localization of TAMs, as defined by expression of CD68. Abundance of TAMs was correlated with clinicopathologic characteristics, tumor recurrence and patients’ survival. Statistical analysis was performed using SPSS software. Patients with high density of TAMs in tumor invasive front (TIF) showed significantly higher local and overall tumor recurrence (both ρ < 0.05). Furthermore, high density of TAMs was associated with decreased overall (one-year 83.6 % vs. 75.1 %; three-year 61.3 % vs. 42.4 %; both ρ < 0.05) and recurrence-free survival (one-year 93.9 % vs. 57.4 %; three-year 59.8 % vs. 26.2 %; both ρ < 0.05). TAMs in TIF and tumor recurrence, were confirmed as the only independent prognostic variables in the multivariate survival analysis (all ρ < 0.05). Overall survival and recurrence free survival of patients with hilar cholangiocarcinoma significantly improved in patients with low levels of TAMs in the area of TIF, when compared to those with a high density of TAMs. These observations suggest their utilization as valuable prognostic markers in routine histopathologic evaluation, and might indicate future therapeutic approaches by targeting TAMs

Factors that influence the selection and utilization of children’s medical insurance

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Shishu Zhang

2015-12-01

Full Text Available The researchers analyzed how different regions in the USA, family structure, ethnicity, and family income levels influenced the selection and utilization of medical care programs and services by American children. To prevent any possible bias in the analysis and to produce reliable results, an endogenous switching model was utilized in the study. The researchers found no statistically significant differences in the number of doctor visits and hospital stays between children with insurance and children without insurance. However, significant differences were determined regarding family structure, family income, geographic regions, and ethnicity. Children from single-parent families with insurance coverage (private, Medicaid, or SCHIP had statistically higher rates of doctor visits and hospital stays than children from two-parent families with insurance coverage. Family income, region, and ethnicity variables all had significant impacts on the type of health insurance coverage that was reported for children.

On a curvature-statistics theorem

International Nuclear Information System (INIS)

Calixto, M; Aldaya, V

2008-01-01

The spin-statistics theorem in quantum field theory relates the spin of a particle to the statistics obeyed by that particle. Here we investigate an interesting correspondence or connection between curvature (κ = ±1) and quantum statistics (Fermi-Dirac and Bose-Einstein, respectively). The interrelation between both concepts is established through vacuum coherent configurations of zero modes in quantum field theory on the compact O(3) and noncompact O(2; 1) (spatial) isometry subgroups of de Sitter and Anti de Sitter spaces, respectively. The high frequency limit, is retrieved as a (zero curvature) group contraction to the Newton-Hooke (harmonic oscillator) group. We also make some comments on the physical significance of the vacuum energy density and the cosmological constant problem.

On a curvature-statistics theorem

Energy Technology Data Exchange (ETDEWEB)

Calixto, M [Departamento de Matematica Aplicada y Estadistica, Universidad Politecnica de Cartagena, Paseo Alfonso XIII 56, 30203 Cartagena (Spain); Aldaya, V [Instituto de Astrofisica de Andalucia, Apartado Postal 3004, 18080 Granada (Spain)], E-mail: Manuel.Calixto@upct.es

2008-08-15

The spin-statistics theorem in quantum field theory relates the spin of a particle to the statistics obeyed by that particle. Here we investigate an interesting correspondence or connection between curvature ({kappa} = {+-}1) and quantum statistics (Fermi-Dirac and Bose-Einstein, respectively). The interrelation between both concepts is established through vacuum coherent configurations of zero modes in quantum field theory on the compact O(3) and noncompact O(2; 1) (spatial) isometry subgroups of de Sitter and Anti de Sitter spaces, respectively. The high frequency limit, is retrieved as a (zero curvature) group contraction to the Newton-Hooke (harmonic oscillator) group. We also make some comments on the physical significance of the vacuum energy density and the cosmological constant problem.

Powerlessness, destiny, and control: the influence on health behaviors of African Americans.

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Green, B Lee; Lewis, Rhonda K; Wang, Min Qi; Person, Sharina; Rivers, Brian

2004-02-01

This study assessed the extent to which a belief in fate or destiny might explain certain health behaviors among African Americans. A survey of 1,253 African Americans in Alabama churches was conducted. Fifty-nine percent of the total sample indicated that they believe in fate or destiny. The findings of this study suggest that fate/destiny may influence health decisions. The study found a statistically significant difference between men and women regarding their belief in fate or destiny. Women reported believing in fate and destiny more than men. Surprisingly people with more education (i.e., college or postgraduate) believed in fate and destiny significantly more than high school dropouts and high school graduates. A belief in fate or destiny also varied by income level. Respondents who made more in annual income were more likely to believe in fate and destiny than people who made less. One behavior, breast exam had a statistically significant association with a belief in fate and destiny. Women who reported never having a breast exam were more likely to believe in fate and destiny than women who did not have a belief in fate or destiny. These findings highlight the need for practitioners to examine more closely the definition of fate and destiny and determine how this belief influences or does not influence health behaviors as once believed. The research suggests a closer examination of the role culture plays in health decision making which may be independent of a belief in fate and destiny.

Statistical exploration of dataset examining key indicators influencing housing and urban infrastructure investments in megacities

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Adedeji O. Afolabi

2018-06-01

Full Text Available Lagos, by the UN standards, has attained the megacity status, with the attendant challenges of living up to that titanic position; regrettably it struggles with its present stock of housing and infrastructural facilities to match its new status. Based on a survey of construction professionals’ perception residing within the state, a questionnaire instrument was used to gather the dataset. The statistical exploration contains dataset on the state of housing and urban infrastructural deficit, key indicators spurring the investment by government to upturn the deficit and improvement mechanisms to tackle the infrastructural dearth. Descriptive statistics and inferential statistics were used to present the dataset. The dataset when analyzed can be useful for policy makers, local and international governments, world funding bodies, researchers and infrastructural investors. Keywords: Construction, Housing, Megacities, Population, Urban infrastructures

A Guideline to Univariate Statistical Analysis for LC/MS-Based Untargeted Metabolomics-Derived Data

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Maria Vinaixa

2012-10-01

Full Text Available Several metabolomic software programs provide methods for peak picking, retention time alignment and quantification of metabolite features in LC/MS-based metabolomics. Statistical analysis, however, is needed in order to discover those features significantly altered between samples. By comparing the retention time and MS/MS data of a model compound to that from the altered feature of interest in the research sample, metabolites can be then unequivocally identified. This paper reports on a comprehensive overview of a workflow for statistical analysis to rank relevant metabolite features that will be selected for further MS/MS experiments. We focus on univariate data analysis applied in parallel on all detected features. Characteristics and challenges of this analysis are discussed and illustrated using four different real LC/MS untargeted metabolomic datasets. We demonstrate the influence of considering or violating mathematical assumptions on which univariate statistical test rely, using high-dimensional LC/MS datasets. Issues in data analysis such as determination of sample size, analytical variation, assumption of normality and homocedasticity, or correction for multiple testing are discussed and illustrated in the context of our four untargeted LC/MS working examples.

Testing statistical hypotheses of equivalence

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Wellek, Stefan

2010-01-01

Equivalence testing has grown significantly in importance over the last two decades, especially as its relevance to a variety of applications has become understood. Yet published work on the general methodology remains scattered in specialists' journals, and for the most part, it focuses on the relatively narrow topic of bioequivalence assessment.With a far broader perspective, Testing Statistical Hypotheses of Equivalence provides the first comprehensive treatment of statistical equivalence testing. The author addresses a spectrum of specific, two-sided equivalence testing problems, from the

Influence of MRI abnormality in skull base bone on prognosis of nasopharyngeal carcinoma

International Nuclear Information System (INIS)

Jin-Cheng, Lu; Qing, Wei; Yi-Qin, Zhang; Feng, Li

2004-01-01

Purpose. To evaluate the influence of skull base bone (SBB) abnormality showed by MRI on prognosis of nasopharyngeal carcinoma (NPC). Patients and methods. From March 1993 to December 1998, 122 NPC patients received prime radiotherapy treatment. All of them were proved pathologically and checked by magnetic resonance imaging (MRI). Every patient received radiation through conjoint facio-cervical field and conventional dose-fractionation schedules. The total dose to the primary tumor was 60 5 Gy (median, 70 Gy). The Kaplan Meier method, the Log-rank test and the Cox regression model were used to evaluate the significance of prognostic factors on NPC patient survival. Results. The overall median survival period was 50 (6 2) months, and the 1, 3 and 5 year-survival rates were, respectively, 99.2%, 87.9%, and 73.3%. The 1, 3, and 5 year-survival rates of abnormality and normality of the SBB on MRI were 98.9%, 87.2%, 71.9%, and 100.0%, 89.8%, 77.0%, respectively (P 0.4233). Gender, age, head pain, SBB abnormality, cranial nerve palsy, cervical lymphadenopathy and primary tumor extent were analyzed with the Cox regression model and SBB abnormality on MRI did not prove to have statistical significance (P = 0.6934). According to the analysis of regrouping, patients with SBB abnormalities ≥ sites have a worse prognosis (P = 0.0427). Then. the above seven factors are analyzed by Cox regression model and the result had statistical significance (P = 0.0385). Conclusion. The SBB abnormality on MRI is of no obvious influence on prognosis of NPC. However, when SBB abnormality sites were ≥ 2, there is obvious statistical significance on the prognosis. (author)

Energy-level statistics and time relaxation in quantum systems

International Nuclear Information System (INIS)

Gruver, J.L.; Cerdeira, H.A.; Aliaga, J.; Mello, P.A.; Proto, A.N.

1997-05-01

We study a quantum-mechanical system, prepared, at t = 0, in a model state, that subsequently decays into a sea of other states whose energy levels form a discrete spectrum with given statistical properties. An important quantity is the survival probability P(t), defined as the probability, at time t, to find the system in the original model state. Our main purpose is to analyze the influence of the discreteness and statistical properties of the spectrum on the behavior of P(t). Since P(t) itself is a statistical quantity, we restrict our attention to its ensemble average , which is calculated analytically using random-matrix techniques, within certain approximations discussed in the text. We find, for , an exponential decay, followed by a revival, governed by the two-point structure of the statistical spectrum, thus giving a nonzero asymptotic value for large t's. The analytic result compares well with a number of computer simulations, over a time range discussed in the text. (author). 17 refs, 1 fig

Western classical music development: a statistical analysis of composers similarity, differentiation and evolution.

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Georges, Patrick

2017-01-01

This paper proposes a statistical analysis that captures similarities and differences between classical music composers with the eventual aim to understand why particular composers 'sound' different even if their 'lineages' (influences network) are similar or why they 'sound' alike if their 'lineages' are different. In order to do this we use statistical methods and measures of association or similarity (based on presence/absence of traits such as specific 'ecological' characteristics and personal musical influences) that have been developed in biosystematics, scientometrics, and bibliographic coupling. This paper also represents a first step towards a more ambitious goal of developing an evolutionary model of Western classical music.

Sirolimus influence on hepatectomy-induced liver regeneration in rats

Directory of Open Access Journals (Sweden)

Edimar Leandro Toderke

Full Text Available OBJECTIVE: To evaluate the influence of sirolimus on liver regeneration triggered by resection of 70% of the liver of adult rats. METHODS: we used 40 Wistar rats randomly divided into two groups (study and control, each group was divided into two equal subgroups according to the day of death (24 hours and seven days. Sirolimus was administered at a dose of 1mg/kg in the study group and the control group was given 1 ml of saline. The solutions were administered daily since three days before hepatectomy till the rats death to removal of the regenerated liver, conducted in 24 hours or 7 days after hepatectomy. Liver regeneration was measured by the KWON formula, by thenumber of mitotic figures (hematoxylin-eosin staining and by the immunohistochemical markers PCNA and Ki-67. RESULTS: there was a statistically significant difference between the 24h and the 7d groups. When comparing the study and control groups in the same period, there was a statistically significant variation only for Ki-67, in which there were increased numbers of hepatocytes in cell multiplication in the 7d study group compared with the 7d control group (p = 0.04. CONCLUSION: there was no negative influence of sirolimus in liver regeneration and there was a positive partial effect at immunohistochemistry with Ki-67.

Influence of Adaptive Statistical Iterative Reconstruction on coronary plaque analysis in coronary computed tomography angiography

DEFF Research Database (Denmark)

Precht, Helle; Kitslaar, Pieter H; Broersen, Alexander

2016-01-01

performed. Images were reconstructed using FBP, 30% and 60% adaptive statistical IR (ASIR). Coronary plaque analysis was performed as per patient and per vessel (LM, LAD, CX and RCA) measurements. Lumen and vessel volumes and plaque burden measurements were based on automatic detected contours in each...... reconstruction. Lumen and plaque intensity measurements and HU based plaque characterization were based on corrected contours copied to each reconstruction. RESULTS: No significant changes between FBP and 30% ASIR were found except for lumen- (-2.53 HU) and plaque intensities (-1.28 HU). Between FBP and 60% ASIR...... the change in total volume showed an increase of 0.94%, 4.36% and 2.01% for lumen, plaque and vessel, respectively. The change in total plaque burden between FBP and 60% ASIR was 0.76%. Lumen and plaque intensities decreased between FBP and 60% ASIR with -9.90 HU and -1.97 HU, respectively. The total plaque...

Calculating statistical distributions from operator relations: The statistical distributions of various intermediate statistics

International Nuclear Information System (INIS)

Dai, Wu-Sheng; Xie, Mi

2013-01-01

In this paper, we give a general discussion on the calculation of the statistical distribution from a given operator relation of creation, annihilation, and number operators. Our result shows that as long as the relation between the number operator and the creation and annihilation operators can be expressed as a † b=Λ(N) or N=Λ −1 (a † b), where N, a † , and b denote the number, creation, and annihilation operators, i.e., N is a function of quadratic product of the creation and annihilation operators, the corresponding statistical distribution is the Gentile distribution, a statistical distribution in which the maximum occupation number is an arbitrary integer. As examples, we discuss the statistical distributions corresponding to various operator relations. In particular, besides the Bose–Einstein and Fermi–Dirac cases, we discuss the statistical distributions for various schemes of intermediate statistics, especially various q-deformation schemes. Our result shows that the statistical distributions corresponding to various q-deformation schemes are various Gentile distributions with different maximum occupation numbers which are determined by the deformation parameter q. This result shows that the results given in much literature on the q-deformation distribution are inaccurate or incomplete. -- Highlights: ► A general discussion on calculating statistical distribution from relations of creation, annihilation, and number operators. ► A systemic study on the statistical distributions corresponding to various q-deformation schemes. ► Arguing that many results of q-deformation distributions in literature are inaccurate or incomplete

Statistical learning in social action contexts.

Science.gov (United States)

Monroy, Claire; Meyer, Marlene; Gerson, Sarah; Hunnius, Sabine

2017-01-01

Sensitivity to the regularities and structure contained within sequential, goal-directed actions is an important building block for generating expectations about the actions we observe. Until now, research on statistical learning for actions has solely focused on individual action sequences, but many actions in daily life involve multiple actors in various interaction contexts. The current study is the first to investigate the role of statistical learning in tracking regularities between actions performed by different actors, and whether the social context characterizing their interaction influences learning. That is, are observers more likely to track regularities across actors if they are perceived as acting jointly as opposed to in parallel? We tested adults and toddlers to explore whether social context guides statistical learning and-if so-whether it does so from early in development. In a between-subjects eye-tracking experiment, participants were primed with a social context cue between two actors who either shared a goal of playing together ('Joint' condition) or stated the intention to act alone ('Parallel' condition). In subsequent videos, the actors performed sequential actions in which, for certain action pairs, the first actor's action reliably predicted the second actor's action. We analyzed predictive eye movements to upcoming actions as a measure of learning, and found that both adults and toddlers learned the statistical regularities across actors when their actions caused an effect. Further, adults with high statistical learning performance were sensitive to social context: those who observed actors with a shared goal were more likely to correctly predict upcoming actions. In contrast, there was no effect of social context in the toddler group, regardless of learning performance. These findings shed light on how adults and toddlers perceive statistical regularities across actors depending on the nature of the observed social situation and the

Statistical analysis of installed wind capacity in the United States

International Nuclear Information System (INIS)

Staid, Andrea; Guikema, Seth D.

2013-01-01

There is a large disparity in the amount of wind power capacity installed in each of the states in the U.S. It is often thought that the different policies of individual state governments are the main reason for these differences, but this may not necessarily be the case. The aim of this paper is to use statistical methods to study the factors that have the most influence on the amount of installed wind capacity in each state. From this analysis, we were able to use these variables to accurately predict the installed wind capacity and to gain insight into the driving factors for wind power development and the reasons behind the differences among states. Using our best model, we find that the most important variables for explaining the amount of wind capacity have to do with the physical and geographic characteristics of the state as opposed to policies in place that favor renewable energy. - Highlights: • We conduct a statistical analysis of factors influencing wind capacity in the U.S. • We find that state policies do not strongly influence the differences among states. • Driving factors are wind resources, cropland area, and available percentage of land

Statistical and theoretical research

International Nuclear Information System (INIS)

Anon.

1983-01-01

Significant accomplishments include the creation of field designs to detect population impacts, new census procedures for small mammals, and methods for designing studies to determine where and how much of a contaminant is extent over certain landscapes. A book describing these statistical methods is currently being written and will apply to a variety of environmental contaminants, including radionuclides. PNL scientists also have devised an analytical method for predicting the success of field eexperiments on wild populations. Two highlights of current research are the discoveries that population of free-roaming horse herds can double in four years and that grizzly bear populations may be substantially smaller than once thought. As stray horses become a public nuisance at DOE and other large Federal sites, it is important to determine their number. Similar statistical theory can be readily applied to other situations where wild animals are a problem of concern to other government agencies. Another book, on statistical aspects of radionuclide studies, is written specifically for researchers in radioecology

Significance analysis of lexical bias in microarray data

Directory of Open Access Journals (Sweden)

Falkow Stanley

2003-04-01

Full Text Available Abstract Background Genes that are determined to be significantly differentially regulated in microarray analyses often appear to have functional commonalities, such as being components of the same biochemical pathway. This results in certain words being under- or overrepresented in the list of genes. Distinguishing between biologically meaningful trends and artifacts of annotation and analysis procedures is of the utmost importance, as only true biological trends are of interest for further experimentation. A number of sophisticated methods for identification of significant lexical trends are currently available, but these methods are generally too cumbersome for practical use by most microarray users. Results We have developed a tool, LACK, for calculating the statistical significance of apparent lexical bias in microarray datasets. The frequency of a user-specified list of search terms in a list of genes which are differentially regulated is assessed for statistical significance by comparison to randomly generated datasets. The simplicity of the input files and user interface targets the average microarray user who wishes to have a statistical measure of apparent lexical trends in analyzed datasets without the need for bioinformatics skills. The software is available as Perl source or a Windows executable. Conclusion We have used LACK in our laboratory to generate biological hypotheses based on our microarray data. We demonstrate the program's utility using an example in which we confirm significant upregulation of SPI-2 pathogenicity island of Salmonella enterica serovar Typhimurium by the cation chelator dipyridyl.

Factors that influence peripheral nerve regeneration

DEFF Research Database (Denmark)

Krarup, Christian; Archibald, Simon J; Madison, Roger D

2002-01-01

median nerve lesions (n = 46) in nonhuman primates over 3 to 4 years, a time span comparable with such lesions in humans. Nerve gap distances of 5, 20, or 50mm were repaired with nerve grafts or collagen-based nerve guide tubes, and three electrophysiological outcome measures were followed: (1) compound...... muscle action potentials in the abductor pollicis brevis muscle, (2) the number and size of motor units in reinnervated muscle, and (3) compound sensory action potentials from digital nerve. A statistical model was used to assess the influence of three variables (repair type, nerve gap distance, and time...... to earliest muscle reinnervation) on the final recovery of the outcome measures. Nerve gap distance and the repair type, individually and concertedly, strongly influenced the time to earliest muscle reinnervation, and only time to reinnervation was significant when all three variables were included as outcome...

Whither Statistics Education Research?

Science.gov (United States)

Watson, Jane

2016-01-01

This year marks the 25th anniversary of the publication of a "National Statement on Mathematics for Australian Schools", which was the first curriculum statement this country had including "Chance and Data" as a significant component. It is hence an opportune time to survey the history of the related statistics education…

Robustness of S1 statistic with Hodges-Lehmann for skewed distributions

Science.gov (United States)

Ahad, Nor Aishah; Yahaya, Sharipah Soaad Syed; Yin, Lee Ping

2016-10-01

Analysis of variance (ANOVA) is a common use parametric method to test the differences in means for more than two groups when the populations are normally distributed. ANOVA is highly inefficient under the influence of non- normal and heteroscedastic settings. When the assumptions are violated, researchers are looking for alternative such as Kruskal-Wallis under nonparametric or robust method. This study focused on flexible method, S1 statistic for comparing groups using median as the location estimator. S1 statistic was modified by substituting the median with Hodges-Lehmann and the default scale estimator with the variance of Hodges-Lehmann and MADn to produce two different test statistics for comparing groups. Bootstrap method was used for testing the hypotheses since the sampling distributions of these modified S1 statistics are unknown. The performance of the proposed statistic in terms of Type I error was measured and compared against the original S1 statistic, ANOVA and Kruskal-Wallis. The propose procedures show improvement compared to the original statistic especially under extremely skewed distribution.

Statistics

CERN Document Server

Hayslett, H T

1991-01-01

Statistics covers the basic principles of Statistics. The book starts by tackling the importance and the two kinds of statistics; the presentation of sample data; the definition, illustration and explanation of several measures of location; and the measures of variation. The text then discusses elementary probability, the normal distribution and the normal approximation to the binomial. Testing of statistical hypotheses and tests of hypotheses about the theoretical proportion of successes in a binomial population and about the theoretical mean of a normal population are explained. The text the

Statistical contribution in the giant multipolar resonance decay in hevay nuclei

International Nuclear Information System (INIS)

Teruya, N.

1986-01-01

Statistical calculations are made for the decay in the electric monopole giant resonance in 208 Pb and electric dipole giant resonance in 209 Bi, using the Hauser-Feshbach formalism. Calculations are done using the experimental energy levels of the corresponding residual nuclei. The particle-vibrator model is used for those experimental levels without spin and parity determination. The influence of different parametrizations of the optical potential in the statistical calculation result is also studied. (L.C.) [pt

Statistical and low dose response

International Nuclear Information System (INIS)

Thorson, M.R.; Endres, G.W.R.

1981-01-01

The low dose response and the lower limit of detection of the Hanford dosimeter depend upon may factors, including the energy of the radiation, whether the exposure is to be a single radiation or mixed fields, annealing cycles, environmental factors, and how well various batches of TLD materials are matched in the system. A careful statistical study and sensitivity analysis were performed to determine how these factors influence the response of the dosimeter system. Estimates have been included in this study of the standard deviation of calculated dose for various mixed field exposures from 0 to 1000 mrem

New scanning technique using Adaptive Statistical Iterative Reconstruction (ASIR) significantly reduced the radiation dose of cardiac CT.

Science.gov (United States)

Tumur, Odgerel; Soon, Kean; Brown, Fraser; Mykytowycz, Marcus

2013-06-01

The aims of our study were to evaluate the effect of application of Adaptive Statistical Iterative Reconstruction (ASIR) algorithm on the radiation dose of coronary computed tomography angiography (CCTA) and its effects on image quality of CCTA and to evaluate the effects of various patient and CT scanning factors on the radiation dose of CCTA. This was a retrospective study that included 347 consecutive patients who underwent CCTA at a tertiary university teaching hospital between 1 July 2009 and 20 September 2011. Analysis was performed comparing patient demographics, scan characteristics, radiation dose and image quality in two groups of patients in whom conventional Filtered Back Projection (FBP) or ASIR was used for image reconstruction. There were 238 patients in the FBP group and 109 patients in the ASIR group. There was no difference between the groups in the use of prospective gating, scan length or tube voltage. In ASIR group, significantly lower tube current was used compared with FBP group, 550 mA (450-600) vs. 650 mA (500-711.25) (median (interquartile range)), respectively, P ASIR group compared with FBP group, 4.29 mSv (2.84-6.02) vs. 5.84 mSv (3.88-8.39) (median (interquartile range)), respectively, P ASIR was associated with increased image noise compared with FBP (39.93 ± 10.22 vs. 37.63 ± 18.79 (mean ± standard deviation), respectively, P ASIR reduces the radiation dose of CCTA without affecting the image quality. © 2013 The Authors. Journal of Medical Imaging and Radiation Oncology © 2013 The Royal Australian and New Zealand College of Radiologists.

Parametric Statistics of Individual Energy Levels in Random Hamiltonians

OpenAIRE

Smolyarenko, I. E.; Simons, B. D.

2002-01-01

We establish a general framework to explore parametric statistics of individual energy levels in disordered and chaotic quantum systems of unitary symmetry. The method is applied to the calculation of the universal intra-level parametric velocity correlation function and the distribution of level shifts under the influence of an arbitrary external perturbation.

General renormalized statistical approach with finite cross-field correlations

International Nuclear Information System (INIS)

Vakulenko, M.O.

1992-01-01

The renormalized statistical approach is proposed, accounting for finite correlations of potential and magnetic fluctuations. It may be used for analysis of a wide class of nonlinear model equations describing the cross-correlated plasma states. The influence of a cross spectrum on stationary potential and magnetic ones is investigated. 10 refs. (author)

Industrial commodity statistics yearbook 2001. Production statistics (1992-2001)

International Nuclear Information System (INIS)

2003-01-01

This is the thirty-fifth in a series of annual compilations of statistics on world industry designed to meet both the general demand for information of this kind and the special requirements of the United Nations and related international bodies. Beginning with the 1992 edition, the title of the publication was changed to industrial Commodity Statistics Yearbook as the result of a decision made by the United Nations Statistical Commission at its twenty-seventh session to discontinue, effective 1994, publication of the Industrial Statistics Yearbook, volume I, General Industrial Statistics by the Statistics Division of the United Nations. The United Nations Industrial Development Organization (UNIDO) has become responsible for the collection and dissemination of general industrial statistics while the Statistics Division of the United Nations continues to be responsible for industrial commodity production statistics. The previous title, Industrial Statistics Yearbook, volume II, Commodity Production Statistics, was introduced in the 1982 edition. The first seven editions in this series were published under the title The Growth of World industry and the next eight editions under the title Yearbook of Industrial Statistics. This edition of the Yearbook contains annual quantity data on production of industrial commodities by country, geographical region, economic grouping and for the world. A standard list of about 530 commodities (about 590 statistical series) has been adopted for the publication. The statistics refer to the ten-year period 1992-2001 for about 200 countries and areas

Industrial commodity statistics yearbook 2002. Production statistics (1993-2002)

International Nuclear Information System (INIS)

2004-01-01

This is the thirty-sixth in a series of annual compilations of statistics on world industry designed to meet both the general demand for information of this kind and the special requirements of the United Nations and related international bodies. Beginning with the 1992 edition, the title of the publication was changed to industrial Commodity Statistics Yearbook as the result of a decision made by the United Nations Statistical Commission at its twenty-seventh session to discontinue, effective 1994, publication of the Industrial Statistics Yearbook, volume I, General Industrial Statistics by the Statistics Division of the United Nations. The United Nations Industrial Development Organization (UNIDO) has become responsible for the collection and dissemination of general industrial statistics while the Statistics Division of the United Nations continues to be responsible for industrial commodity production statistics. The previous title, Industrial Statistics Yearbook, volume II, Commodity Production Statistics, was introduced in the 1982 edition. The first seven editions in this series were published under the title 'The Growth of World industry' and the next eight editions under the title 'Yearbook of Industrial Statistics'. This edition of the Yearbook contains annual quantity data on production of industrial commodities by country, geographical region, economic grouping and for the world. A standard list of about 530 commodities (about 590 statistical series) has been adopted for the publication. The statistics refer to the ten-year period 1993-2002 for about 200 countries and areas

Industrial commodity statistics yearbook 2000. Production statistics (1991-2000)

International Nuclear Information System (INIS)

2002-01-01

This is the thirty-third in a series of annual compilations of statistics on world industry designed to meet both the general demand for information of this kind and the special requirements of the United Nations and related international bodies. Beginning with the 1992 edition, the title of the publication was changed to industrial Commodity Statistics Yearbook as the result of a decision made by the United Nations Statistical Commission at its twenty-seventh session to discontinue, effective 1994, publication of the Industrial Statistics Yearbook, volume I, General Industrial Statistics by the Statistics Division of the United Nations. The United Nations Industrial Development Organization (UNIDO) has become responsible for the collection and dissemination of general industrial statistics while the Statistics Division of the United Nations continues to be responsible for industrial commodity production statistics. The previous title, Industrial Statistics Yearbook, volume II, Commodity Production Statistics, was introduced in the 1982 edition. The first seven editions in this series were published under the title The Growth of World industry and the next eight editions under the title Yearbook of Industrial Statistics. This edition of the Yearbook contains annual quantity data on production of industrial commodities by country, geographical region, economic grouping and for the world. A standard list of about 530 commodities (about 590 statistical series) has been adopted for the publication. Most of the statistics refer to the ten-year period 1991-2000 for about 200 countries and areas

Pregnancy and oral contraceptive use do not significantly influence outcome in long term rheumatoid arthritis

NARCIS (Netherlands)

Drossaers-Bakker, K. W.; Zwinderman, A. H.; van Zeben, D.; Breedveld, F. C.; Hazes, J. M. W.

2002-01-01

BACKGROUND: Oral contraceptives (OC) and pregnancy are known to have an influence on the risk of onset of rheumatoid arthritis (RA). Pregnancy itself has beneficial effects on the activity of the disease, with relapses post partum. It is not known, however, whether OC and pregnancies influence the

Macro-indicators of citation impacts of six prolific countries: InCites data and the statistical significance of trends.

Directory of Open Access Journals (Sweden)

Lutz Bornmann

Full Text Available Using the InCites tool of Thomson Reuters, this study compares normalized citation impact values calculated for China, Japan, France, Germany, United States, and the UK throughout the time period from 1981 to 2010. InCites offers a unique opportunity to study the normalized citation impacts of countries using (i a long publication window (1981 to 2010, (ii a differentiation in (broad or more narrow subject areas, and (iii allowing for the use of statistical procedures in order to obtain an insightful investigation of national citation trends across the years. Using four broad categories, our results show significantly increasing trends in citation impact values for France, the UK, and especially Germany across the last thirty years in all areas. The citation impact of papers from China is still at a relatively low level (mostly below the world average, but the country follows an increasing trend line. The USA exhibits a stable pattern of high citation impact values across the years. With small impact differences between the publication years, the US trend is increasing in engineering and technology but decreasing in medical and health sciences as well as in agricultural sciences. Similar to the USA, Japan follows increasing as well as decreasing trends in different subject areas, but the variability across the years is small. In most of the years, papers from Japan perform below or approximately at the world average in each subject area.

Statistical selection of tide gauges for Arctic sea-level reconstruction

DEFF Research Database (Denmark)

Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

2015-01-01

In this paper, we seek an appropriate selection of tide gauges for Arctic Ocean sea-level reconstruction based on a combination of empirical criteria and statistical properties (leverages). Tide gauges provide the only in situ observations of sea level prior to the altimetry era. However, tide...... the "influence" of each Arctic tide gauge on the EOF-based reconstruction through the use of statistical leverage and use this as an indication in selecting appropriate tide gauges, in order to procedurally identify poor-quality data while still including as much data as possible. To accommodate sparse...

Childhood-compared to adolescent-onset bipolar disorder has more statistically significant clinical correlates.

Science.gov (United States)

Holtzman, Jessica N; Miller, Shefali; Hooshmand, Farnaz; Wang, Po W; Chang, Kiki D; Hill, Shelley J; Rasgon, Natalie L; Ketter, Terence A

2015-07-01

The strengths and limitations of considering childhood-and adolescent-onset bipolar disorder (BD) separately versus together remain to be established. We assessed this issue. BD patients referred to the Stanford Bipolar Disorder Clinic during 2000-2011 were assessed with the Systematic Treatment Enhancement Program for BD Affective Disorders Evaluation. Patients with childhood- and adolescent-onset were compared to those with adult-onset for 7 unfavorable bipolar illness characteristics with replicated associations with early-onset patients. Among 502 BD outpatients, those with childhood- (adolescent- (13-18 years, N=218) onset had significantly higher rates for 4/7 unfavorable illness characteristics, including lifetime comorbid anxiety disorder, at least ten lifetime mood episodes, lifetime alcohol use disorder, and prior suicide attempt, than those with adult-onset (>18 years, N=174). Childhood- but not adolescent-onset BD patients also had significantly higher rates of first-degree relative with mood disorder, lifetime substance use disorder, and rapid cycling in the prior year. Patients with pooled childhood/adolescent - compared to adult-onset had significantly higher rates for 5/7 of these unfavorable illness characteristics, while patients with childhood- compared to adolescent-onset had significantly higher rates for 4/7 of these unfavorable illness characteristics. Caucasian, insured, suburban, low substance abuse, American specialty clinic-referred sample limits generalizability. Onset age is based on retrospective recall. Childhood- compared to adolescent-onset BD was more robustly related to unfavorable bipolar illness characteristics, so pooling these groups attenuated such relationships. Further study is warranted to determine the extent to which adolescent-onset BD represents an intermediate phenotype between childhood- and adult-onset BD. Copyright © 2015 Elsevier B.V. All rights reserved.

Influence of mammal fossorial activity on the soil fermentative activity in conditions of metallurgical production

Directory of Open Access Journals (Sweden)

S. M. Kirienko

2010-09-01

Full Text Available Effect of mammal fossorial activity as an ecological factor of the soil genesis intensification is studied. Enzymatic activity of soil as its ability to demonstrate a catalytic effect for various compounds transformation is examined. Variability of soil urease activity in technogenic conditions with the participation of animals is shown. The positive influence of animals’ activity on the catalitic ability of the investigated soils was determined. The statistically significant characteristics which have an influence on the urease activity in soil are found out.

Encounter Probability of Significant Wave Height

DEFF Research Database (Denmark)

Liu, Z.; Burcharth, H. F.

The determination of the design wave height (often given as the significant wave height) is usually based on statistical analysis of long-term extreme wave height measurement or hindcast. The result of such extreme wave height analysis is often given as the design wave height corresponding to a c...

Emergency Department Crowding: Factors Influencing Flow

Directory of Open Access Journals (Sweden)

Arkun, Alp

2010-02-01

Full Text Available Background: The objective of this study was to evaluate those factors, both intrinsic and extrinsic to the emergency department (ED that influence two specific components of throughput: “door-to-doctor” time and dwell time.Methods: We used a prospective observational study design to determine the variables that played a significant role in determining ED flow. All adult patients seen or waiting to be seen in the ED were observed at 8pm (Monday-Friday during a three-month period. Variables measured included daily ED volume, patient acuity, staffing, ED occupancy, daily admissions, ED boarder volume, hospital volume, and intensive care unit volume. Both log-rank tests and time-to-wait (survival proportional-hazard regression models were fitted to determine which variables were most significant in predicting “door-to-doctor” and dwell times, with full account of the censoring for some patients.Results: We captured 1,543 patients during our study period, representing 27% of total daily volume. The ED operated at an average of 85% capacity (61-102% with an average of 27% boarding. Median “door-to-doctor” time was 1.8 hours, with the biggest influence being triage category, day of the week, and ED occupancy. Median dwell time was 5.5 hours with similar variable influences.Conclusion: The largest contributors to decreased patient flow through the ED at our institution were triage category, ED occupancy, and day of the week. Although the statistically significant factors influencing patient throughput at our institution involve problems with inflow, an increase in ED occupancy could be due to substantial outflow obstruction and may indicate the necessity for increased capacity both within the ED and hospital. [West J Emerg Med. 2010; 11(1:10-15

Estimation of measurement variance in the context of environment statistics

Science.gov (United States)

Maiti, Pulakesh

2015-02-01

The object of environment statistics is for providing information on the environment, on its most important changes over time, across locations and identifying the main factors that influence them. Ultimately environment statistics would be required to produce higher quality statistical information. For this timely, reliable and comparable data are needed. Lack of proper and uniform definitions, unambiguous classifications pose serious problems to procure qualitative data. These cause measurement errors. We consider the problem of estimating measurement variance so that some measures may be adopted to improve upon the quality of data on environmental goods and services and on value statement in economic terms. The measurement technique considered here is that of employing personal interviewers and the sampling considered here is that of two-stage sampling.

Surface pretreatment of plastics with an atmospheric pressure plasma jet - Influence of generator power and kinematics

International Nuclear Information System (INIS)

Moritzer, E.; Leister, C.

2014-01-01

The industrial use of atmospheric pressure plasmas in the plastics processing industry has increased significantly in recent years. Users of this treatment process have the possibility to influence the target values (e.g. bond strength or surface energy) with the help of kinematic and electrical parameters. Until now, systematic procedures have been used with which the parameters can be adapted to the process or product requirements but only by very time-consuming methods. For this reason, the relationship between influencing values and target values will be examined based on the example of a pretreatment in the bonding process with the help of statistical experimental design. Because of the large number of parameters involved, the analysis is restricted to the kinematic and electrical parameters. In the experimental tests, the following factors are taken as parameters: gap between nozzle and substrate, treatment velocity (kinematic data), voltage and duty cycle (electrical data). The statistical evaluation shows significant relationships between the parameters and surface energy in the case of polypropylene. An increase in the voltage and duty cycle increases the polar proportion of the surface energy, while a larger gap and higher velocity leads to lower energy levels. The bond strength of the overlapping bond is also significantly influenced by the voltage, velocity and gap. The direction of their effects is identical with those of the surface energy. In addition to the kinematic influences of the motion of an atmospheric pressure plasma jet, it is therefore especially important that the parameters for the plasma production are taken into account when designing the pretreatment processes

Factors That Influence Mandatory Child Abuse Reporting Attitudes of Pediatric Nurses in Korea.

Science.gov (United States)

Lee, In Sook; Kim, Kyoung Ja

This study aimed to identify knowledge of child abuse, awareness of child abuse reporting, factors that influence attitudes toward mandatory reporting, and professionalism among a sample of pediatric nurses in Korea. One hundred sixteen pediatric nurses working at two university hospitals in Korea took part in the study and completed self-administered questionnaires. The data were analyzed using descriptive statistics, t tests, analysis of variance, Pearson correlation coefficients, and hierarchical regression analysis. Knowledge of child abuse, awareness of child abuse reporting, and attitudes toward mandatory reporting were low. Regarding nursing professionalism, social perceptions had the lowest mean score and nursing autonomy had the highest mean score. Attitudes toward mandatory reporting significantly correlated with professionalism. In the hierarchical regression model, the influences of nursing autonomy and intentions to report child abuse on attitudes toward mandatory reporting were statistically significant (F = 2.176, p = .013), explaining 32% of the variation in attitudes toward mandatory reporting. The results of this study could be used to improve systems and policies addressing child abuse and to further develop reporting procedures for identifying children at risk of abuse, to ensure their protection as a professional responsibility.

Statistical Compilation of the ICT Sector and Policy Analysis | CRDI ...

International Development Research Centre (IDRC) Digital Library (Canada)

Statistical Compilation of the ICT Sector and Policy Analysis. As the presence and influence of information and communication technologies (ICTs) continues to widen and deepen, so too does its impact on economic development. However, much work needs to be done before the linkages between economic development ...

Statistical Compilation of the ICT Sector and Policy Analysis | IDRC ...

International Development Research Centre (IDRC) Digital Library (Canada)

Statistical Compilation of the ICT Sector and Policy Analysis. As the presence and influence of information and communication technologies (ICTs) continues to widen and deepen, so too does its impact on economic development. However, much work needs to be done before the linkages between economic development ...

[Influence of diet and behavior related factors on the peripheral blood triglyceride levels in adults: a cross-sectional study].

Science.gov (United States)

Liang, M B; Wang, H; Zhang, J; He, Q F; Fang, L; Wang, L X; Su, D T; Zhao, M; Zhang, X W; Hu, R Y; Cong, L M; Ding, G G; Ye, Z; Yu, M

2017-12-10

Objective: To study the influence of diet and behavior related factors on the peripheral blood triglyceride levels in adults, through a cross-sectional survey. Methods: The current study included 13 434 subjects without histories of major chronic diseases from a population-based cross-sectional survey: the 2010 Metabolic Syndrome Survey in Zhejiang Province. A generalized linear model was used to investigate the influence of diet/behavior-related factors on the peripheral blood triglyceride levels. Results: Mean TG of the sample population appeared as (1.36±1.18) mmol/L. The proportions of elevated TG and marginally elevated TG were 10.3% and 11.0% respectively, with statistically significant difference seen between males and females ( χ (2)=44.135, P smoking, alcohol-intake, meat, fruit and water intake in male population from this study. However, in females, the intake of aquatic product and physical exercise showed statistically significant differences. After controlling for other variables, factors as age, drinking, staple food and aquatic products showed positive influence on TG, while milk presented negative influence on TG. Through interaction analysis, fruit and meat intake in males and staple food in females showed positive influence on TG, when compared to the reference group. Conclusion: Hyperglyceridemia appeared as one of the major metabolic abnormities in Zhejiang province. Programs on monitoring the alcohol, staple food and meat intake should be priority on intervention, in the communities.

[Comment on] Statistical discrimination

Science.gov (United States)

Chinn, Douglas

In the December 8, 1981, issue of Eos, a news item reported the conclusion of a National Research Council study that sexual discrimination against women with Ph.D.'s exists in the field of geophysics. Basically, the item reported that even when allowances are made for motherhood the percentage of female Ph.D.'s holding high university and corporate positions is significantly lower than the percentage of male Ph.D.'s holding the same types of positions. The sexual discrimination conclusion, based only on these statistics, assumes that there are no basic psychological differences between men and women that might cause different populations in the employment group studied. Therefore, the reasoning goes, after taking into account possible effects from differences related to anatomy, such as women stopping their careers in order to bear and raise children, the statistical distributions of positions held by male and female Ph.D.'s ought to be very similar to one another. Any significant differences between the distributions must be caused primarily by sexual discrimination.

Global Repetition Influences Contextual Cueing

Science.gov (United States)

Zang, Xuelian; Zinchenko, Artyom; Jia, Lina; Li, Hong

2018-01-01

Our visual system has a striking ability to improve visual search based on the learning of repeated ambient regularities, an effect named contextual cueing. Whereas most of the previous studies investigated contextual cueing effect with the same number of repeated and non-repeated search displays per block, the current study focused on whether a global repetition frequency formed by different presentation ratios between the repeated and non-repeated configurations influence contextual cueing effect. Specifically, the number of repeated and non-repeated displays presented in each block was manipulated: 12:12, 20:4, 4:20, and 4:4 in Experiments 1–4, respectively. The results revealed a significant contextual cueing effect when the global repetition frequency is high (≥1:1 ratio) in Experiments 1, 2, and 4, given that processing of repeated displays was expedited relative to non-repeated displays. Nevertheless, the contextual cueing effect reduced to a non-significant level when the repetition frequency reduced to 4:20 in Experiment 3. These results suggested that the presentation frequency of repeated relative to the non-repeated displays could influence the strength of contextual cueing. In other words, global repetition statistics could be a crucial factor to mediate contextual cueing effect. PMID:29636716

TRENDS IN URBAN STORM WATER QUALITY IN TALLINN AND INFLUENCES FROM STORMFLOW AND BASEFLOW

Directory of Open Access Journals (Sweden)

Bharat Maharjan

2016-04-01

Full Text Available Temporal trends provide a good interpretation of change in stormwater quality over time. This study aimed to analyse trends and influences due to stormflow and baseflow. Grab samples of 18-19 years from 1995 to 2014 recorded at outlets of 7 Tallinn watersheds were analysed for monotonic trend through seasonal Mann Kendall test for long-term, short-term, baseflow and stormflow. Statistically significant downward trends (P-value (p 0.05 and < 0.2 for 3 – SS, 1 – BOD, 1 – TN and 1 – TP were identified. Statistically significant long-term upward trends of pH were revealed in 5 basins, which reduced to 2 with 5 less significant upward trends over the 10 year period, indicating improvements in pH reduction. Härjapea has the highest pH without trend but it includes an upward trend of TN at p = 0.051. The highly possible causes for downward trends are street sweeping, sewer network improvement, decline in sub-urban agricultural areas, etc. The upward trend results of pH are related to increased alkalinisation due to acidic rain, weathering of carbonate rocks, sewage discharge and alkaline road dust. In most of the basins, stormflow has more influence on trends than baseflow.

'Am I as smart as my smart meter is?' - Swedish experience of statistics feedback to households

Energy Technology Data Exchange (ETDEWEB)

Pyrko, Jurek (Lund University, Dept. of Energy Sciences (Sweden))

2011-07-01

This paper presents a synthesis of three cases from a study 'Information through digital channels and its potential to change electricity consumption patterns' within Elforsk ELAN-programme, AMR-Visualisation carried out by scientists from the Efficient Energy Use in Buildings Research Group at the Department of Energy Sciences, Lund University - LTH, Sweden. The main objective was to investigate the influence of improved energy feedback (Internet-based energy statistics services) on electricity savings and the potential of changing electricity use patterns in Swedish dwellings. The three case studies were conducted in collaboration with respective grid companies. The analysis integrated both quantitative and qualitative methods in order to investigate different aspects of customers' electricity consumption, energy behaviour, values and attitudes. Periods 'before' and 'after' the introduction of feedback measure were used. The customers were not influenced by the observations. An energy profile that would explore differences between users and non-users of the services (in terms of energy-related habits and behaviour) was used. The main hypothesis of this study assumed that the statistics service, as feedback to households, might lead to lower electricity consumption, thanks to better understanding of energy use patterns and costs. This hypothesis was not confirmed. The results of this study can be summarized in the following conclusions: - The users of the statistics service have shown either reduced or increased electricity use in the households. - The explanation why the households using the statistics service often have had increasing electricity usage could be that their rising power consumption caused a need to have better control over electricity needs and energy bills, and households started to use the statistics services for this reason. - The results did not confirm that users of statistics services have had significantly

Harmonic statistics

International Nuclear Information System (INIS)

Eliazar, Iddo

2017-01-01

The exponential, the normal, and the Poisson statistical laws are of major importance due to their universality. Harmonic statistics are as universal as the three aforementioned laws, but yet they fall short in their ‘public relations’ for the following reason: the full scope of harmonic statistics cannot be described in terms of a statistical law. In this paper we describe harmonic statistics, in their full scope, via an object termed harmonic Poisson process: a Poisson process, over the positive half-line, with a harmonic intensity. The paper reviews the harmonic Poisson process, investigates its properties, and presents the connections of this object to an assortment of topics: uniform statistics, scale invariance, random multiplicative perturbations, Pareto and inverse-Pareto statistics, exponential growth and exponential decay, power-law renormalization, convergence and domains of attraction, the Langevin equation, diffusions, Benford’s law, and 1/f noise. - Highlights: • Harmonic statistics are described and reviewed in detail. • Connections to various statistical laws are established. • Connections to perturbation, renormalization and dynamics are established.

Harmonic statistics

Energy Technology Data Exchange (ETDEWEB)

Eliazar, Iddo, E-mail: eliazar@post.tau.ac.il

2017-05-15

The exponential, the normal, and the Poisson statistical laws are of major importance due to their universality. Harmonic statistics are as universal as the three aforementioned laws, but yet they fall short in their ‘public relations’ for the following reason: the full scope of harmonic statistics cannot be described in terms of a statistical law. In this paper we describe harmonic statistics, in their full scope, via an object termed harmonic Poisson process: a Poisson process, over the positive half-line, with a harmonic intensity. The paper reviews the harmonic Poisson process, investigates its properties, and presents the connections of this object to an assortment of topics: uniform statistics, scale invariance, random multiplicative perturbations, Pareto and inverse-Pareto statistics, exponential growth and exponential decay, power-law renormalization, convergence and domains of attraction, the Langevin equation, diffusions, Benford’s law, and 1/f noise. - Highlights: • Harmonic statistics are described and reviewed in detail. • Connections to various statistical laws are established. • Connections to perturbation, renormalization and dynamics are established.

Statistical mechanics for a class of quantum statistics

International Nuclear Information System (INIS)

Isakov, S.B.

1994-01-01

Generalized statistical distributions for identical particles are introduced for the case where filling a single-particle quantum state by particles depends on filling states of different momenta. The system of one-dimensional bosons with a two-body potential that can be solved by means of the thermodynamic Bethe ansatz is shown to be equivalent thermodynamically to a system of free particles obeying statistical distributions of the above class. The quantum statistics arising in this way are completely determined by the two-particle scattering phases of the corresponding interacting systems. An equation determining the statistical distributions for these statistics is derived

The Influence of Atmosphere on the Oxidation of Ground Walnut During Storage at 20 °C

Directory of Open Access Journals (Sweden)

Rajko Vidrih

2012-01-01

Full Text Available The aim of this study is to determine the impact of atmosphere on the oxidation of ground walnut during storage at 20 °C. Seven varieties of walnut (Juglans regia L. were ground and stored under O2 or N2 atmospheres in hermetically sealed vials for 10 months at room temperature. Antioxidative potential, total phenolic content, fatty acid composition, and oxidative degradation products were determined after 10 months of storage. Cultivar, atmosphere and cultivar×atmosphere interactions significantly influenced the antioxidative potential. Cultivar and atmosphere significantly influenced the content of total polyphenols, with more polyphenols found in walnut stored in the N2 atmosphere. The mass fraction of unsaturated linolenic acid tended to decrease during storage under the O2 atmosphere; statistically significant differences were only found between individual varieties. The O2 atmosphere also resulted in an increase in the synthesis of oxidative degradation products. Among the degradation products, hexanal was the most abundant volatile compound, followed by 1-octen-3-ol, octanal, as well as the mixture of 2-octenal and 1-octen-3-ol. In general, higher concentrations of these degradation products were found in walnut stored under the O2 atmosphere, although these differences were statistically significant only between individual varieties for some compounds.

Data-driven inference for the spatial scan statistic.

Science.gov (United States)

Almeida, Alexandre C L; Duarte, Anderson R; Duczmal, Luiz H; Oliveira, Fernando L P; Takahashi, Ricardo H C

2011-08-02

Kulldorff's spatial scan statistic for aggregated area maps searches for clusters of cases without specifying their size (number of areas) or geographic location in advance. Their statistical significance is tested while adjusting for the multiple testing inherent in such a procedure. However, as is shown in this work, this adjustment is not done in an even manner for all possible cluster sizes. A modification is proposed to the usual inference test of the spatial scan statistic, incorporating additional information about the size of the most likely cluster found. A new interpretation of the results of the spatial scan statistic is done, posing a modified inference question: what is the probability that the null hypothesis is rejected for the original observed cases map with a most likely cluster of size k, taking into account only those most likely clusters of size k found under null hypothesis for comparison? This question is especially important when the p-value computed by the usual inference process is near the alpha significance level, regarding the correctness of the decision based in this inference. A practical procedure is provided to make more accurate inferences about the most likely cluster found by the spatial scan statistic.

A statistical analysis of the body condition of cows from two veterinary stations in Zimbabwe

International Nuclear Information System (INIS)

Saporu, F.W.O.

2003-12-01

The improvement of livestock production is important for Zimbabwe's agriculturally base economy. This paper examines the relationship between the body condition and metabolic parameters of female cows, for the better understanding of traditional livestock farming in Zimbabwe. The data analysed are part of the baseline data on the improvement of livestock production, collected from two sites Chinamora and Bulawayo. Body condition is indexed by body score. Thirty-five variables are examined. The variable selection method employed is stepwise regression. Regression model assumptions of normality and independent observations are checked using normal probability plot and Durbin-Watson statistics for autocorrelation of residuals. Collinearity and outlier problems are examined using eigenanalysis and influence statistics. The effect of some factors, such as, site, which relates to livestock management, parity and season, categorized by the quality of forage available for grazing, are also studied. The data are analysed using SAS statistical package on a Personal Computer. The results show that only about four variables substantially influence the relationship in each of the two sites considered. For the better managed site, Bulawayo, these are PCV, Calcium and WBC. Strongyles, Progesterone Level, Phosphate and HB are obtained in Chinamora. Negative correlation coefficient corresponds to strongyles only. That is, the effect of stronglyes is to reduce the value of bodyscore. For other variables, an improvement in their respective values will bring about improved body condition. Site difference is identified as a factor affecting the relationship. This emphasizes the role of good management in livestock production. Parity and season are also identified. Only two interactions are significant; site-season and a progesterone level-season interaction. The latter is obtained only in Chinamora site and it can be deduced that the cyclic cows are exposed to the risk of loosing their

New distributions of the statistical time delay of electrical breakdown in nitrogen

International Nuclear Information System (INIS)

Markovic, V Lj; Gocic, S R; Stamenkovic, S N

2006-01-01

Two new distributions of the statistical time delay of electrical breakdown in nitrogen are reported in this paper. The Gaussian and Gauss-exponential distributions of statistical time delay have been obtained on the basis of thousands of time delay measurements on a gas tube with a plane-parallel electrode system. Distributions of the statistical time delay are theoretically founded on binomial distribution for the occurrence of initiating electrons and described by using simple analytical and numerical models. The shapes of distributions depend on the electron yields in the interelectrode space originating from residual states. It is shown that a distribution of the statistical time delay changes from exponential and Gauss-exponential to Gaussian distribution due to the influence of residual ionization

Medical Statistics – Mathematics or Oracle? Farewell Lecture

Directory of Open Access Journals (Sweden)

Gaus, Wilhelm

2005-06-01

Full Text Available Certainty is rare in medicine. This is a direct consequence of the individuality of each and every human being and the reason why we need medical statistics. However, statistics have their pitfalls, too. Fig. 1 shows that the suicide rate peaks in youth, while in Fig. 2 the rate is highest in midlife and Fig. 3 in old age. Which of these contradictory messages is right? After an introduction to the principles of statistical testing, this lecture examines the probability with which statistical test results are correct. For this purpose the level of significance and the power of the test are compared with the sensitivity and specificity of a diagnostic procedure. The probability of obtaining correct statistical test results is the same as that for the positive and negative correctness of a diagnostic procedure and therefore depends on prevalence. The focus then shifts to the problem of multiple statistical testing. The lecture demonstrates that for each data set of reasonable size at least one test result proves to be significant - even if the data set is produced by a random number generator. It is extremely important that a hypothesis is generated independently from the data used for its testing. These considerations enable us to understand the gradation of "lame excuses, lies and statistics" and the difference between pure truth and the full truth. Finally, two historical oracles are cited.

Topics in statistical and theoretical physics

CERN Document Server

Dobrushin, R L; Shubin, M A

1996-01-01

This is the second of two volumes dedicated to the scientific heritage of F. A. Berezin (1931-1980). Before his untimely death, Berezin had an important influence on physics and mathematics, discovering new ideas in mathematical physics, representation theory, analysis, geometry, and other areas of mathematics. His crowning achievements were the introduction of a new notion of deformation quantization and Grassmannian analysis ("supermathematics"). Collected here are papers by many of his colleagues and others who worked in related areas, representing a wide spectrum of topics in statistical a

Evidence for significant influence of host immunity on changes in differential blood count during malaria.

Science.gov (United States)

Berens-Riha, Nicole; Kroidl, Inge; Schunk, Mirjam; Alberer, Martin; Beissner, Marcus; Pritsch, Michael; Kroidl, Arne; Fröschl, Günter; Hanus, Ingrid; Bretzel, Gisela; von Sonnenburg, Frank; Nothdurft, Hans Dieter; Löscher, Thomas; Herbinger, Karl-Heinz

2014-04-23

Malaria has been shown to change blood counts. Recently, a few studies have investigated the alteration of the peripheral blood monocyte-to-lymphocyte count ratio (MLCR) and the neutrophil-to-lymphocyte count ratio (NLCR) during infection with Plasmodium falciparum. Based on these findings this study investigates the predictive values of blood count alterations during malaria across different sub-populations. Cases and controls admitted to the Department of Infectious Diseases and Tropical Medicine from January 2000 through December 2010 were included in this comparative analysis. Blood count values and other variables at admission controlled for age, gender and immune status were statistically investigated. The study population comprised 210 malaria patients, infected with P. falciparum (68%), Plasmodium vivax (21%), Plasmodium ovale (7%) and Plasmodium malariae (4%), and 210 controls. A positive correlation of parasite density with NLCR and neutrophil counts, and a negative correlation of parasite density with thrombocyte, leucocyte and lymphocyte counts were found. An interaction with semi-immunity was observed; ratios were significantly different in semi-immune compared to non-immune patients (P value of the ratios was fair but limited. However, these changes were less pronounced in patients with semi-immunity. The ratios might constitute easily applicable surrogate biomarkers for immunity.

Predicting axillary lymph node metastasis from kinetic statistics of DCE-MRI breast images

Science.gov (United States)

Ashraf, Ahmed B.; Lin, Lilie; Gavenonis, Sara C.; Mies, Carolyn; Xanthopoulos, Eric; Kontos, Despina

2012-03-01

The presence of axillary lymph node metastases is the most important prognostic factor in breast cancer and can influence the selection of adjuvant therapy, both chemotherapy and radiotherapy. In this work we present a set of kinetic statistics derived from DCE-MRI for predicting axillary node status. Breast DCE-MRI images from 69 women with known nodal status were analyzed retrospectively under HIPAA and IRB approval. Axillary lymph nodes were positive in 12 patients while 57 patients had no axillary lymph node involvement. Kinetic curves for each pixel were computed and a pixel-wise map of time-to-peak (TTP) was obtained. Pixels were first partitioned according to the similarity of their kinetic behavior, based on TTP values. For every kinetic curve, the following pixel-wise features were computed: peak enhancement (PE), wash-in-slope (WIS), wash-out-slope (WOS). Partition-wise statistics for every feature map were calculated, resulting in a total of 21 kinetic statistic features. ANOVA analysis was done to select features that differ significantly between node positive and node negative women. Using the computed kinetic statistic features a leave-one-out SVM classifier was learned that performs with AUC=0.77 under the ROC curve, outperforming the conventional kinetic measures, including maximum peak enhancement (MPE) and signal enhancement ratio (SER), (AUCs of 0.61 and 0.57 respectively). These findings suggest that our DCE-MRI kinetic statistic features can be used to improve the prediction of axillary node status in breast cancer patients. Such features could ultimately be used as imaging biomarkers to guide personalized treatment choices for women diagnosed with breast cancer.

Testing for significance of phase synchronisation dynamics in the EEG.

Science.gov (United States)

Daly, Ian; Sweeney-Reed, Catherine M; Nasuto, Slawomir J

2013-06-01

A number of tests exist to check for statistical significance of phase synchronisation within the Electroencephalogram (EEG); however, the majority suffer from a lack of generality and applicability. They may also fail to account for temporal dynamics in the phase synchronisation, regarding synchronisation as a constant state instead of a dynamical process. Therefore, a novel test is developed for identifying the statistical significance of phase synchronisation based upon a combination of work characterising temporal dynamics of multivariate time-series and Markov modelling. We show how this method is better able to assess the significance of phase synchronisation than a range of commonly used significance tests. We also show how the method may be applied to identify and classify significantly different phase synchronisation dynamics in both univariate and multivariate datasets.

New scanning technique using Adaptive Statistical lterative Reconstruction (ASIR) significantly reduced the radiation dose of cardiac CT

International Nuclear Information System (INIS)

Tumur, Odgerel; Soon, Kean; Brown, Fraser; Mykytowycz, Marcus

2013-01-01

The aims of our study were to evaluate the effect of application of Adaptive Statistical Iterative Reconstruction (ASIR) algorithm on the radiation dose of coronary computed tomography angiography (CCTA) and its effects on image quality of CCTA and to evaluate the effects of various patient and CT scanning factors on the radiation dose of CCTA. This was a retrospective study that included 347 consecutive patients who underwent CCTA at a tertiary university teaching hospital between 1 July 2009 and 20 September 2011. Analysis was performed comparing patient demographics, scan characteristics, radiation dose and image quality in two groups of patients in whom conventional Filtered Back Projection (FBP) or ASIR was used for image reconstruction. There were 238 patients in the FBP group and 109 patients in the ASIR group. There was no difference between the groups in the use of prospective gating, scan length or tube voltage. In ASIR group, significantly lower tube current was used compared with FBP group, 550mA (450–600) vs. 650mA (500–711.25) (median (interquartile range)), respectively, P<0.001. There was 27% effective radiation dose reduction in the ASIR group compared with FBP group, 4.29mSv (2.84–6.02) vs. 5.84mSv (3.88–8.39) (median (interquartile range)), respectively, P<0.001. Although ASIR was associated with increased image noise compared with FBP (39.93±10.22 vs. 37.63±18.79 (mean ±standard deviation), respectively, P<001), it did not affect the signal intensity, signal-to-noise ratio, contrast-to-noise ratio or the diagnostic quality of CCTA. Application of ASIR reduces the radiation dose of CCTA without affecting the image quality.

Conversion factors and oil statistics

International Nuclear Information System (INIS)

Karbuz, Sohbet

2004-01-01

World oil statistics, in scope and accuracy, are often far from perfect. They can easily lead to misguided conclusions regarding the state of market fundamentals. Without proper attention directed at statistic caveats, the ensuing interpretation of oil market data opens the door to unnecessary volatility, and can distort perception of market fundamentals. Among the numerous caveats associated with the compilation of oil statistics, conversion factors, used to produce aggregated data, play a significant role. Interestingly enough, little attention is paid to conversion factors, i.e. to the relation between different units of measurement for oil. Additionally, the underlying information regarding the choice of a specific factor when trying to produce measurements of aggregated data remains scant. The aim of this paper is to shed some light on the impact of conversion factors for two commonly encountered issues, mass to volume equivalencies (barrels to tonnes) and for broad energy measures encountered in world oil statistics. This paper will seek to demonstrate how inappropriate and misused conversion factors can yield wildly varying results and ultimately distort oil statistics. Examples will show that while discrepancies in commonly used conversion factors may seem trivial, their impact on the assessment of a world oil balance is far from negligible. A unified and harmonised convention for conversion factors is necessary to achieve accurate comparisons and aggregate oil statistics for the benefit of both end-users and policy makers

Influence of adaptive statistical iterative reconstruction algorithm on image quality in coronary computed tomography angiography.

Science.gov (United States)

Precht, Helle; Thygesen, Jesper; Gerke, Oke; Egstrup, Kenneth; Waaler, Dag; Lambrechtsen, Jess

2016-12-01

Coronary computed tomography angiography (CCTA) requires high spatial and temporal resolution, increased low contrast resolution for the assessment of coronary artery stenosis, plaque detection, and/or non-coronary pathology. Therefore, new reconstruction algorithms, particularly iterative reconstruction (IR) techniques, have been developed in an attempt to improve image quality with no cost in radiation exposure. To evaluate whether adaptive statistical iterative reconstruction (ASIR) enhances perceived image quality in CCTA compared to filtered back projection (FBP). Thirty patients underwent CCTA due to suspected coronary artery disease. Images were reconstructed using FBP, 30% ASIR, and 60% ASIR. Ninety image sets were evaluated by five observers using the subjective visual grading analysis (VGA) and assessed by proportional odds modeling. Objective quality assessment (contrast, noise, and the contrast-to-noise ratio [CNR]) was analyzed with linear mixed effects modeling on log-transformed data. The need for ethical approval was waived by the local ethics committee as the study only involved anonymously collected clinical data. VGA showed significant improvements in sharpness by comparing FBP with ASIR, resulting in odds ratios of 1.54 for 30% ASIR and 1.89 for 60% ASIR ( P  = 0.004). The objective measures showed significant differences between FBP and 60% ASIR ( P  < 0.0001) for noise, with an estimated ratio of 0.82, and for CNR, with an estimated ratio of 1.26. ASIR improved the subjective image quality of parameter sharpness and, objectively, reduced noise and increased CNR.

Abnormal white matter integrity in the corpus callosum among smokers: tract-based spatial statistics.

Directory of Open Access Journals (Sweden)

Wakako Umene-Nakano

Full Text Available In the present study, we aimed to investigate the difference in white matter between smokers and nonsmokers. In addition, we examined relationships between white matter integrity and nicotine dependence parameters in smoking subjects. Nineteen male smokers were enrolled in this study. Eighteen age-matched non-smokers with no current or past psychiatric history were included as controls. Diffusion tensor imaging scans were performed, and the analysis was conducted using a tract-based special statistics approach. Compared with nonsmokers, smokers exhibited a significant decrease in fractional anisotropy (FA throughout the whole corpus callosum. There were no significant differences in radial diffusivity or axial diffusivity between the two groups. There was a significant negative correlation between FA in the whole corpus callosum and the amount of tobacco use (cigarettes/day; R = - 0.580, p = 0.023. These results suggest that the corpus callosum may be one of the key areas influenced by chronic smoking.

Statistical inquiry on the reliability of emergency diesel stations in German nuclear power plants

International Nuclear Information System (INIS)

1983-01-01

This statistic inquiry is based on 692 occurrances in 40 diesel stations of 10 German nuclear power plants. Various parameters influencing the failure behaviour of diesel stations were investigated on only significant plant-specific influences and the impact of diesel station circuitry on failure behaviour were established. According to the results of this inquiry, running time, start-up number and increasing operational experience do not apparently influence the failure behaviour of diesel stations. The expected failure probability of diesel stations varies with the different nuclear power plants. Taking into account both start-up and operational failures, (with monthly inspections and running times of up to 2 h), this value is in the range of 1.6 x 10 -2 to 1.7 x 10 -3 per application. Considering failure data of all diesel stations, the failure probability (start-up and operational failures) is 8.1 x 10 -3 per application. On account of the two common-mode failures registered, a common-mode failure probability of 10 -3 was established. The inquiry also showed that non-availability of diesel stations is essentially determined by maintenance intervals. (orig.) [de

Statistics with JMP graphs, descriptive statistics and probability

CERN Document Server

Goos, Peter

2015-01-01

Peter Goos, Department of Statistics, University ofLeuven, Faculty of Bio-Science Engineering and University ofAntwerp, Faculty of Applied Economics, BelgiumDavid Meintrup, Department of Mathematics and Statistics,University of Applied Sciences Ingolstadt, Faculty of MechanicalEngineering, GermanyThorough presentation of introductory statistics and probabilitytheory, with numerous examples and applications using JMPDescriptive Statistics and Probability provides anaccessible and thorough overview of the most important descriptivestatistics for nominal, ordinal and quantitative data withpartic

Testing University Rankings Statistically: Why this Perhaps is not such a Good Idea after All. Some Reflections on Statistical Power, Effect Size, Random Sampling and Imaginary Populations

DEFF Research Database (Denmark)

Schneider, Jesper Wiborg

2012-01-01

In this paper we discuss and question the use of statistical significance tests in relation to university rankings as recently suggested. We outline the assumptions behind and interpretations of statistical significance tests and relate this to examples from the recent SCImago Institutions Rankin...

The influence of DNA repair inhibitors on the mutation rate

International Nuclear Information System (INIS)

Auzinger, Th.; Hruby, R.

1980-12-01

The simultaneous influence of gamma-radiation and DNA-repair inhibiting substances on the mutation frequency of mice was investigated in vivo with the micronucleus test. The detergens Tween 80, vitamin A, and the antiphlogisticum phenylbutazone were used as DNA-repair inhibiting substances. Using the same irradiation doses, a statistic significant increase of mutagenicity respectively micronucleus frequency was found in high concentrations of Tween 80 and in all used dosages of vitamin A, but not in phenylbutazone and in low concentrations of tween. (auth.)

High-Throughput Nanoindentation for Statistical and Spatial Property Determination

Science.gov (United States)

Hintsala, Eric D.; Hangen, Ude; Stauffer, Douglas D.

2018-04-01

Standard nanoindentation tests are "high throughput" compared to nearly all other mechanical tests, such as tension or compression. However, the typical rates of tens of tests per hour can be significantly improved. These higher testing rates enable otherwise impractical studies requiring several thousands of indents, such as high-resolution property mapping and detailed statistical studies. However, care must be taken to avoid systematic errors in the measurement, including choosing of the indentation depth/spacing to avoid overlap of plastic zones, pileup, and influence of neighboring microstructural features in the material being tested. Furthermore, since fast loading rates are required, the strain rate sensitivity must also be considered. A review of these effects is given, with the emphasis placed on making complimentary standard nanoindentation measurements to address these issues. Experimental applications of the technique, including mapping of welds, microstructures, and composites with varying length scales, along with studying the effect of surface roughness on nominally homogeneous specimens, will be presented.

Uncertainty the soul of modeling, probability & statistics

CERN Document Server

Briggs, William

2016-01-01

This book presents a philosophical approach to probability and probabilistic thinking, considering the underpinnings of probabilistic reasoning and modeling, which effectively underlie everything in data science. The ultimate goal is to call into question many standard tenets and lay the philosophical and probabilistic groundwork and infrastructure for statistical modeling. It is the first book devoted to the philosophy of data aimed at working scientists and calls for a new consideration in the practice of probability and statistics to eliminate what has been referred to as the "Cult of Statistical Significance". The book explains the philosophy of these ideas and not the mathematics, though there are a handful of mathematical examples. The topics are logically laid out, starting with basic philosophy as related to probability, statistics, and science, and stepping through the key probabilistic ideas and concepts, and ending with statistical models. Its jargon-free approach asserts that standard methods, suc...

Statistics of high-level scene context.

Science.gov (United States)

Greene, Michelle R

2013-01-01

CONTEXT IS CRITICAL FOR RECOGNIZING ENVIRONMENTS AND FOR SEARCHING FOR OBJECTS WITHIN THEM: contextual associations have been shown to modulate reaction time and object recognition accuracy, as well as influence the distribution of eye movements and patterns of brain activations. However, we have not yet systematically quantified the relationships between objects and their scene environments. Here I seek to fill this gap by providing descriptive statistics of object-scene relationships. A total of 48, 167 objects were hand-labeled in 3499 scenes using the LabelMe tool (Russell et al., 2008). From these data, I computed a variety of descriptive statistics at three different levels of analysis: the ensemble statistics that describe the density and spatial distribution of unnamed "things" in the scene; the bag of words level where scenes are described by the list of objects contained within them; and the structural level where the spatial distribution and relationships between the objects are measured. The utility of each level of description for scene categorization was assessed through the use of linear classifiers, and the plausibility of each level for modeling human scene categorization is discussed. Of the three levels, ensemble statistics were found to be the most informative (per feature), and also best explained human patterns of categorization errors. Although a bag of words classifier had similar performance to human observers, it had a markedly different pattern of errors. However, certain objects are more useful than others, and ceiling classification performance could be achieved using only the 64 most informative objects. As object location tends not to vary as a function of category, structural information provided little additional information. Additionally, these data provide valuable information on natural scene redundancy that can be exploited for machine vision, and can help the visual cognition community to design experiments guided by statistics

Statistical process control in nursing research.

Science.gov (United States)

Polit, Denise F; Chaboyer, Wendy

2012-02-01

In intervention studies in which randomization to groups is not possible, researchers typically use quasi-experimental designs. Time series designs are strong quasi-experimental designs but are seldom used, perhaps because of technical and analytic hurdles. Statistical process control (SPC) is an alternative analytic approach to testing hypotheses about intervention effects using data collected over time. SPC, like traditional statistical methods, is a tool for understanding variation and involves the construction of control charts that distinguish between normal, random fluctuations (common cause variation), and statistically significant special cause variation that can result from an innovation. The purpose of this article is to provide an overview of SPC and to illustrate its use in a study of a nursing practice improvement intervention. Copyright © 2011 Wiley Periodicals, Inc.

Statistics Anxiety and Business Statistics: The International Student

Science.gov (United States)

Bell, James A.

2008-01-01

Does the international student suffer from statistics anxiety? To investigate this, the Statistics Anxiety Rating Scale (STARS) was administered to sixty-six beginning statistics students, including twelve international students and fifty-four domestic students. Due to the small number of international students, nonparametric methods were used to…

Statistics of Parameter Estimates: A Concrete Example

KAUST Repository

Aguilar, Oscar

2015-01-01

© 2015 Society for Industrial and Applied Mathematics. Most mathematical models include parameters that need to be determined from measurements. The estimated values of these parameters and their uncertainties depend on assumptions made about noise levels, models, or prior knowledge. But what can we say about the validity of such estimates, and the influence of these assumptions? This paper is concerned with methods to address these questions, and for didactic purposes it is written in the context of a concrete nonlinear parameter estimation problem. We will use the results of a physical experiment conducted by Allmaras et al. at Texas A&M University [M. Allmaras et al., SIAM Rev., 55 (2013), pp. 149-167] to illustrate the importance of validation procedures for statistical parameter estimation. We describe statistical methods and data analysis tools to check the choices of likelihood and prior distributions, and provide examples of how to compare Bayesian results with those obtained by non-Bayesian methods based on different types of assumptions. We explain how different statistical methods can be used in complementary ways to improve the understanding of parameter estimates and their uncertainties.

Changing world extreme temperature statistics

Science.gov (United States)

Finkel, J. M.; Katz, J. I.

2018-04-01

We use the Global Historical Climatology Network--daily database to calculate a nonparametric statistic that describes the rate at which all-time daily high and low temperature records have been set in nine geographic regions (continents or major portions of continents) during periods mostly from the mid-20th Century to the present. This statistic was defined in our earlier work on temperature records in the 48 contiguous United States. In contrast to this earlier work, we find that in every region except North America all-time high records were set at a rate significantly (at least $3\\sigma$) higher than in the null hypothesis of a stationary climate. Except in Antarctica, all-time low records were set at a rate significantly lower than in the null hypothesis. In Europe, North Africa and North Asia the rate of setting new all-time highs increased suddenly in the 1990's, suggesting a change in regional climate regime; in most other regions there was a steadier increase.

Applying Statistical Mechanics to pixel detectors

International Nuclear Information System (INIS)

Pindo, Massimiliano

2002-01-01

Pixel detectors, being made of a large number of active cells of the same kind, can be considered as significant sets to which Statistical Mechanics variables and methods can be applied. By properly redefining well known statistical parameters in order to let them match the ones that actually characterize pixel detectors, an analysis of the way they work can be performed in a totally new perspective. A deeper understanding of pixel detectors is attained, helping in the evaluation and comparison of their intrinsic characteristics and performance

Introductory statistics for the behavioral sciences

CERN Document Server

Welkowitz, Joan; Cohen, Jacob

1971-01-01

Introductory Statistics for the Behavioral Sciences provides an introduction to statistical concepts and principles. This book emphasizes the robustness of parametric procedures wherein such significant tests as t and F yield accurate results even if such assumptions as equal population variances and normal population distributions are not well met.Organized into three parts encompassing 16 chapters, this book begins with an overview of the rationale upon which much of behavioral science research is based, namely, drawing inferences about a population based on data obtained from a samp

Dissipative Effects on Inertial-Range Statistics at High Reynolds Numbers.

Science.gov (United States)

Sinhuber, Michael; Bewley, Gregory P; Bodenschatz, Eberhard

2017-09-29

Using the unique capabilities of the Variable Density Turbulence Tunnel at the Max Planck Institute for Dynamics and Self-Organization, Göttingen, we report experimental measurements in classical grid turbulence that uncover oscillations of the velocity structure functions in the inertial range. This was made possible by measuring extremely long time series of up to 10^{10} samples of the turbulent fluctuating velocity, which corresponds to O(10^{7}) integral length scales. The measurements were conducted in a well-controlled environment at a wide range of high Reynolds numbers from R_{λ}=110 up to R_{λ}=1600, using both traditional hot-wire probes as well as the nanoscale thermal anemometry probe developed at Princeton University. An implication of the observed oscillations is that dissipation influences the inertial-range statistics of turbulent flows at scales significantly larger than predicted by current models and theories.

Spreadsheets as tools for statistical computing and statistics education

OpenAIRE

Neuwirth, Erich

2000-01-01

Spreadsheets are an ubiquitous program category, and we will discuss their use in statistics and statistics education on various levels, ranging from very basic examples to extremely powerful methods. Since the spreadsheet paradigm is very familiar to many potential users, using it as the interface to statistical methods can make statistics more easily accessible.

An Empirical Study of Presage Variables in the Teaching-Learning of Statistics, in the Light of Research on Competencies

Science.gov (United States)

Rodriguez, Clemente; Gutierrez-Perez, Jose; Pozo, Teresa

2010-01-01

Introduction: This research seeks to determine the influence exercised by a set of presage and process variables (students' pre-existing opinion towards statistics, their dedication to mastery of statistics content, assessment of the teaching materials, and the teacher's effort in the teaching of statistics) in students' resolution of activities…

A multimodal wave spectrum-based approach for statistical downscaling of local wave climate

Science.gov (United States)

Hegermiller, Christie; Antolinez, Jose A A; Rueda, Ana C.; Camus, Paula; Perez, Jorge; Erikson, Li; Barnard, Patrick; Mendez, Fernando J.

2017-01-01

Characterization of wave climate by bulk wave parameters is insufficient for many coastal studies, including those focused on assessing coastal hazards and long-term wave climate influences on coastal evolution. This issue is particularly relevant for studies using statistical downscaling of atmospheric fields to local wave conditions, which are often multimodal in large ocean basins (e.g. the Pacific). Swell may be generated in vastly different wave generation regions, yielding complex wave spectra that are inadequately represented by a single set of bulk wave parameters. Furthermore, the relationship between atmospheric systems and local wave conditions is complicated by variations in arrival time of wave groups from different parts of the basin. Here, we address these two challenges by improving upon the spatiotemporal definition of the atmospheric predictor used in statistical downscaling of local wave climate. The improved methodology separates the local wave spectrum into “wave families,” defined by spectral peaks and discrete generation regions, and relates atmospheric conditions in distant regions of the ocean basin to local wave conditions by incorporating travel times computed from effective energy flux across the ocean basin. When applied to locations with multimodal wave spectra, including Southern California and Trujillo, Peru, the new methodology improves the ability of the statistical model to project significant wave height, peak period, and direction for each wave family, retaining more information from the full wave spectrum. This work is the base of statistical downscaling by weather types, which has recently been applied to coastal flooding and morphodynamic applications.

Statistical modeling of Earth's plasmasphere

Science.gov (United States)

Veibell, Victoir

The behavior of plasma near Earth's geosynchronous orbit is of vital importance to both satellite operators and magnetosphere modelers because it also has a significant influence on energy transport, ion composition, and induced currents. The system is highly complex in both time and space, making the forecasting of extreme space weather events difficult. This dissertation examines the behavior and statistical properties of plasma mass density near geosynchronous orbit by using both linear and nonlinear models, as well as epoch analyses, in an attempt to better understand the physical processes that precipitates and drives its variations. It is shown that while equatorial mass density does vary significantly on an hourly timescale when a drop in the disturbance time scale index ( Dst) was observed, it does not vary significantly between the day of a Dst event onset and the day immediately following. It is also shown that increases in equatorial mass density were not, on average, preceded or followed by any significant change in the examined solar wind or geomagnetic variables, including Dst, despite prior results that considered a few selected events and found a notable influence. It is verified that equatorial mass density and and solar activity via the F10.7 index have a strong correlation, which is stronger over longer timescales such as 27 days than it is over an hourly timescale. It is then shown that this connection seems to affect the behavior of equatorial mass density most during periods of strong solar activity leading to large mass density reactions to Dst drops for high values of F10.7. It is also shown that equatorial mass density behaves differently before and after events based on the value of F10.7 at the onset of an equatorial mass density event or a Dst event, and that a southward interplanetary magnetic field at onset leads to slowed mass density growth after event onset. These behavioral differences provide insight into how solar and geomagnetic

An Exploration of the Perceived Usefulness of the Introductory Statistics Course and Students’ Intentions to Further Engage in Statistics

Directory of Open Access Journals (Sweden)

Rossi Hassad

2018-01-01

Full Text Available Students� attitude, including perceived usefulness, is generally associated with academic success. The related research in statistics education has focused almost exclusively on the role of attitude in explaining and predicting academic learning outcomes, hence there is a paucity of research evidence on how attitude (particularly perceived usefulness impacts students� intentions to use and stay engaged in statistics beyond the introductory course. This study explored the relationship between college students� perception of the usefulness of an introductory statistics course, their beliefs about where statistics will be most useful, and their intentions to take another statistics course. A cross-sectional study of 106 students was conducted. The mean rating for usefulness was 4.7 (out of 7, with no statistically significant differences based on gender and age. Sixty-four percent reported that they would consider taking another statistics course, and this subgroup rated the course as more useful (p = .01. The majority (67% reported that statistics would be most useful for either graduate school or research, whereas 14% indicated their job, and 19% were undecided. The �undecided� students had the lowest mean rating for usefulness of the course (p = .001. Addressing data, in the context of real-world problem-solving and decision-making, could facilitate students to better appreciate the usefulness and practicality of statistics. Qualitative research methods could help to elucidate these findings.

Understanding the significance variables for fabrication of fish gelatin nanoparticles by Plackett-Burman design

Science.gov (United States)

Subara, Deni; Jaswir, Irwandi; Alkhatib, Maan Fahmi Rashid; Noorbatcha, Ibrahim Ali

2018-01-01

The aim of this experiment is to screen and to understand the process variables on the fabrication of fish gelatin nanoparticles by using quality-design approach. The most influencing process variables were screened by using Plackett-Burman design. Mean particles size, size distribution, and zeta potential were found in the range 240±9.76 nm, 0.3, and -9 mV, respectively. Statistical results explained that concentration of acetone, pH of solution during precipitation step and volume of cross linker had a most significant effect on particles size of fish gelatin nanoparticles. It was found that, time and chemical consuming is lower than previous research. This study revealed the potential of quality-by design in understanding the effects of process variables on the fish gelatin nanoparticles production.

Dry Sliding Wear Behavior of Super Duplex Stainless Steel AISI 2507: a Statistical Approach

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Davanageri M.

2016-12-01

Full Text Available The dry sliding wear behavior of heat-treated super duplex stainless steel AISI 2507 was examined by taking pin-on-disc type of wear-test rig. Independent parameters, namely applied load, sliding distance, and sliding speed, influence mainly the wear rate of super duplex stainless steel. The said material was heat treated to a temperature of 850°C for 1 hour followed by water quenching. The heat treatment was carried out to precipitate the secondary sigma phase formation. Experiments were conducted to study the influence of independent parameters set at three factor levels using the L27 orthogonal array of the Taguchi experimental design on the wear rate. Statistical significance of both individual and combined factor effects was determined for specific wear rate. Surface plots were drawn to explain the behavior of independent variables on the measured wear rate. Statistically, the models were validated using the analysis of variance test. Multiple non-linear regression equations were derived for wear rate expressed as non-linear functions of independent variables. Further, the prediction accuracy of the developed regression equation was tested with the actual experiments. The independent parameters responsible for the desired minimum wear rate were determined by using the desirability function approach. The worn-out surface characteristics obtained for the minimum wear rate was examined using the scanning electron microscope. The desired smooth surface was obtained for the determined optimal condition by desirability function approach.

Data-driven inference for the spatial scan statistic

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Duczmal Luiz H

2011-08-01

Full Text Available Abstract Background Kulldorff's spatial scan statistic for aggregated area maps searches for clusters of cases without specifying their size (number of areas or geographic location in advance. Their statistical significance is tested while adjusting for the multiple testing inherent in such a procedure. However, as is shown in this work, this adjustment is not done in an even manner for all possible cluster sizes. Results A modification is proposed to the usual inference test of the spatial scan statistic, incorporating additional information about the size of the most likely cluster found. A new interpretation of the results of the spatial scan statistic is done, posing a modified inference question: what is the probability that the null hypothesis is rejected for the original observed cases map with a most likely cluster of size k, taking into account only those most likely clusters of size k found under null hypothesis for comparison? This question is especially important when the p-value computed by the usual inference process is near the alpha significance level, regarding the correctness of the decision based in this inference. Conclusions A practical procedure is provided to make more accurate inferences about the most likely cluster found by the spatial scan statistic.

Register-based statistics statistical methods for administrative data

CERN Document Server

Wallgren, Anders

2014-01-01

This book provides a comprehensive and up to date treatment of  theory and practical implementation in Register-based statistics. It begins by defining the area, before explaining how to structure such systems, as well as detailing alternative approaches. It explains how to create statistical registers, how to implement quality assurance, and the use of IT systems for register-based statistics. Further to this, clear details are given about the practicalities of implementing such statistical methods, such as protection of privacy and the coordination and coherence of such an undertaking. Thi

Cancer Statistics

Science.gov (United States)

... What Is Cancer? Cancer Statistics Cancer Disparities Cancer Statistics Cancer has a major impact on society in ... success of efforts to control and manage cancer. Statistics at a Glance: The Burden of Cancer in ...

Accelerator driven reactors, - the significance of the energy distribution of spallation neutrons on the neutron statistics

Energy Technology Data Exchange (ETDEWEB)

Fhager, V

2000-01-01

In order to make correct predictions of the second moment of statistical nuclear variables, such as the number of fissions and the number of thermalized neutrons, the dependence of the energy distribution of the source particles on their number should be considered. It has been pointed out recently that neglecting this number dependence in accelerator driven systems might result in bad estimates of the second moment, and this paper contains qualitative and quantitative estimates of the size of these efforts. We walk towards the requested results in two steps. First, models of the number dependent energy distributions of the neutrons that are ejected in the spallation reactions are constructed, both by simple assumptions and by extracting energy distributions of spallation neutrons from a high-energy particle transport code. Then, the second moment of nuclear variables in a sub-critical reactor, into which spallation neutrons are injected, is calculated. The results from second moment calculations using number dependent energy distributions for the source neutrons are compared to those where only the average energy distribution is used. Two physical models are employed to simulate the neutron transport in the reactor. One is analytical, treating only slowing down of neutrons by elastic scattering in the core material. For this model, equations are written down and solved for the second moment of thermalized neutrons that include the distribution of energy of the spallation neutrons. The other model utilizes Monte Carlo methods for tracking the source neutrons as they travel inside the reactor material. Fast and thermal fission reactions are considered, as well as neutron capture and elastic scattering, and the second moment of the number of fissions, the number of neutrons that leaked out of the system, etc. are calculated. Both models use a cylindrical core with a homogenous mixture of core material. Our results indicate that the number dependence of the energy

Accelerator driven reactors, - the significance of the energy distribution of spallation neutrons on the neutron statistics

International Nuclear Information System (INIS)

Fhager, V.

2000-01-01

In order to make correct predictions of the second moment of statistical nuclear variables, such as the number of fissions and the number of thermalized neutrons, the dependence of the energy distribution of the source particles on their number should be considered. It has been pointed out recently that neglecting this number dependence in accelerator driven systems might result in bad estimates of the second moment, and this paper contains qualitative and quantitative estimates of the size of these efforts. We walk towards the requested results in two steps. First, models of the number dependent energy distributions of the neutrons that are ejected in the spallation reactions are constructed, both by simple assumptions and by extracting energy distributions of spallation neutrons from a high-energy particle transport code. Then, the second moment of nuclear variables in a sub-critical reactor, into which spallation neutrons are injected, is calculated. The results from second moment calculations using number dependent energy distributions for the source neutrons are compared to those where only the average energy distribution is used. Two physical models are employed to simulate the neutron transport in the reactor. One is analytical, treating only slowing down of neutrons by elastic scattering in the core material. For this model, equations are written down and solved for the second moment of thermalized neutrons that include the distribution of energy of the spallation neutrons. The other model utilizes Monte Carlo methods for tracking the source neutrons as they travel inside the reactor material. Fast and thermal fission reactions are considered, as well as neutron capture and elastic scattering, and the second moment of the number of fissions, the number of neutrons that leaked out of the system, etc. are calculated. Both models use a cylindrical core with a homogenous mixture of core material. Our results indicate that the number dependence of the energy

Social and cultural influences among Mexican border entrepreneurs.

Science.gov (United States)

Díaz Bretones, Francisco; Cappello, Héctor M; Garcia, Pedro A

2009-06-01

Social and cultural conditions (including U.S. border and inland influence, role models within the family, and educational background) which affect locus of control and achievement motivation among Mexican entrepreneurs were explored among 64 selected entrepreneurs in two Mexican towns, one on the Mexico-U.S. border, the other located inland. Analyses showed that the border subsample scored higher on External locus of control; however, in both subsamples the father was an important element in the locus of control variable and the entrepreneur status. No statistically significant mean difference was noted for achievement motivation. Practical applications and limitations are discussed.

Measuring streetscape complexity based on the statistics of local contrast and spatial frequency.

Directory of Open Access Journals (Sweden)

André Cavalcante

Full Text Available Streetscapes are basic urban elements which play a major role in the livability of a city. The visual complexity of streetscapes is known to influence how people behave in such built spaces. However, how and which characteristics of a visual scene influence our perception of complexity have yet to be fully understood. This study proposes a method to evaluate the complexity perceived in streetscapes based on the statistics of local contrast and spatial frequency. Here, 74 streetscape images from four cities, including daytime and nighttime scenes, were ranked for complexity by 40 participants. Image processing was then used to locally segment contrast and spatial frequency in the streetscapes. The statistics of these characteristics were extracted and later combined to form a single objective measure. The direct use of statistics revealed structural or morphological patterns in streetscapes related to the perception of complexity. Furthermore, in comparison to conventional measures of visual complexity, the proposed objective measure exhibits a higher correlation with the opinion of the participants. Also, the performance of this method is more robust regarding different time scenarios.

Influence of schooling on language abilities of adults without linguistic disorders

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Ellen Cristina Siqueira Soares

Full Text Available CONTEXT AND OBJECTIVE: In order to properly assess language, sociodemographic variables that can influence the linguistic performance of individuals with or without linguistic disorders need to be taken into account. The aim of this study was to evaluate the influence of schooling and age on the results from the Montreal Toulouse (Modified MT Beta-86 language assessment test among individuals without linguistic disorders. DESIGN AND SETTING: Cross-sectional study carried out between March 2006 and August 2007 in the Speech, Language and Hearing Pathology Department of Universidade Federal de São Paulo (Unifesp, São Paulo, Brazil. METHODS: Eighty volunteers were selected. Schooling was stratified into three bands: A (1-4 years, B (5-8 years and C (nine years and over. The age range was from 17 to 80 years. All the subjects underwent the Montreal Toulouse (Modified MT Beta-86 language assessment protocol. RESULTS: Statistically significant differences were found in relation to schooling levels, in the tasks of oral comprehension, reading, graphical comprehension, naming, lexical availability, dictation, graphical naming of actions and number reading. Statistically significant age-related differences in dictation and lexical availability tasks were observed. CONCLUSIONS: The Montreal Toulouse (Modified MT Beta-86 test seems to be sensitive to variations in schooling and age. These variables should be taken into account when this test is used for assessing patients with brain damage.

Influence of schooling on language abilities of adults without linguistic disorders.

Science.gov (United States)

Soares, Ellen Cristina Siqueira; Ortiz, Karin Zazo

2009-01-01

In order to properly assess language, sociodemographic variables that can influence the linguistic performance of individuals with or without linguistic disorders need to be taken into account. The aim of this study was to evaluate the influence of schooling and age on the results from the Montreal Toulouse (Modified MT Beta-86) language assessment test among individuals without linguistic disorders. Cross-sectional study carried out between March 2006 and August 2007 in the Speech, Language and Hearing Pathology Department of Universidade Federal de São Paulo (Unifesp), São Paulo, Brazil. Eighty volunteers were selected. Schooling was stratified into three bands: A (1-4 years), B (5-8 years) and C (nine years and over). The age range was from 17 to 80 years. All the subjects underwent the Montreal Toulouse (Modified MT Beta-86) language assessment protocol. Statistically significant differences were found in relation to schooling levels, in the tasks of oral comprehension, reading, graphical comprehension, naming, lexical availability, dictation, graphical naming of actions and number reading. Statistically significant age-related differences in dictation and lexical availability tasks were observed. The Montreal Toulouse (Modified MT Beta-86) test seems to be sensitive to variations in schooling and age. These variables should be taken into account when this test is used for assessing patients with brain damage.

Aplication of the statistical experimental design to optimize mine-impacted water (MIW) remediation using shrimp-shell.

Science.gov (United States)

Núñez-Gómez, Dámaris; Alves, Alcione Aparecida de Almeida; Lapolli, Flavio Rubens; Lobo-Recio, María A

2017-01-01

Mine-impacted water (MIW) is one of the most serious mining problems and has a high negative impact on water resources and aquatic life. The main characteristics of MIW are a low pH (between 2 and 4) and high concentrations of SO 4 2- and metal ions (Cd, Cu, Ni, Pb, Zn, Fe, Al, Cr, Mn, Mg, etc.), many of which are toxic to ecosystems and human life. Shrimp shell was selected as a MIW treatment agent because it is a low-cost metal-sorbent biopolymer with a high chitin content and contains calcium carbonate, an acid-neutralizing agent. To determine the best metal-removal conditions, a statistical study using statistical planning was carried out. Thus, the objective of this work was to identify the degree of influence and dependence of the shrimp-shell content for the removal of Fe, Al, Mn, Co, and Ni from MIW. In this study, a central composite rotational experimental design (CCRD) with a quadruplicate at the midpoint (2 2 ) was used to evaluate the joint influence of two formulation variables-agitation and the shrimp-shell content. The statistical results showed the significant influence (p < 0.05) of the agitation variable for Fe and Ni removal (linear and quadratic form, respectively) and of the shrimp-shell content variable for Mn (linear form), Al and Co (linear and quadratic form) removal. Analysis of variance (ANOVA) for Al, Co, and Ni removal showed that the model is valid at the 95% confidence interval and that no adjustment needed within the ranges evaluated of agitation (0-251.5 rpm) and shrimp-shell content (1.2-12.8 g L -1 ). The model required adjustments to the 90% and 75% confidence interval for Fe and Mn removal, respectively. In terms of efficiency in removing pollutants, it was possible to determine the best experimental values of the variables considered as 188 rpm and 9.36 g L -1 of shrimp-shells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Software Used to Generate Cancer Statistics - SEER Cancer Statistics

Science.gov (United States)

Videos that highlight topics and trends in cancer statistics and definitions of statistical terms. Also software tools for analyzing and reporting cancer statistics, which are used to compile SEER's annual reports.

Influence of adaptive statistical iterative reconstruction algorithm on image quality in coronary computed tomography angiography

Directory of Open Access Journals (Sweden)

Helle Precht

2016-12-01

Full Text Available Background Coronary computed tomography angiography (CCTA requires high spatial and temporal resolution, increased low contrast resolution for the assessment of coronary artery stenosis, plaque detection, and/or non-coronary pathology. Therefore, new reconstruction algorithms, particularly iterative reconstruction (IR techniques, have been developed in an attempt to improve image quality with no cost in radiation exposure. Purpose To evaluate whether adaptive statistical iterative reconstruction (ASIR enhances perceived image quality in CCTA compared to filtered back projection (FBP. Material and Methods Thirty patients underwent CCTA due to suspected coronary artery disease. Images were reconstructed using FBP, 30% ASIR, and 60% ASIR. Ninety image sets were evaluated by five observers using the subjective visual grading analysis (VGA and assessed by proportional odds modeling. Objective quality assessment (contrast, noise, and the contrast-to-noise ratio [CNR] was analyzed with linear mixed effects modeling on log-transformed data. The need for ethical approval was waived by the local ethics committee as the study only involved anonymously collected clinical data. Results VGA showed significant improvements in sharpness by comparing FBP with ASIR, resulting in odds ratios of 1.54 for 30% ASIR and 1.89 for 60% ASIR (P = 0.004. The objective measures showed significant differences between FBP and 60% ASIR (P < 0.0001 for noise, with an estimated ratio of 0.82, and for CNR, with an estimated ratio of 1.26. Conclusion ASIR improved the subjective image quality of parameter sharpness and, objectively, reduced noise and increased CNR.

Statistical Compilation of the ICT Sector and Policy Analysis | Page 4 ...

International Development Research Centre (IDRC) Digital Library (Canada)

Statistical Compilation of the ICT Sector and Policy Analysis. As the presence and influence of information and communication technologies (ICTs) continues to widen and deepen, so too does its impact on economic development. However, much work needs to be done before the linkages between economic development ...

Statistical Compilation of the ICT Sector and Policy Analysis | Page 3 ...

International Development Research Centre (IDRC) Digital Library (Canada)

Statistical Compilation of the ICT Sector and Policy Analysis. As the presence and influence of information and communication technologies (ICTs) continues to widen and deepen, so too does its impact on economic development. However, much work needs to be done before the linkages between economic development ...

Application of statistical experimental design to study the formulation variables influencing the coating process of lidocaine liposomes.

Science.gov (United States)

González-Rodríguez, M L; Barros, L B; Palma, J; González-Rodríguez, P L; Rabasco, A M

2007-06-07

In this paper, we have used statistical experimental design to investigate the effect of several factors in coating process of lidocaine hydrochloride (LID) liposomes by a biodegradable polymer (chitosan, CH). These variables were the concentration of CH coating solution, the dripping rate of this solution on the liposome colloidal dispersion, the stirring rate, the time since the liposome production to the liposome coating and finally the amount of drug entrapped into liposomes. The selected response variables were drug encapsulation efficiency (EE, %), coating efficiency (CE, %) and zeta potential. Liposomes were obtained by thin-layer evaporation method. They were subsequently coated with CH according the experimental plan provided by a fractional factorial (2(5-1)) screening matrix. We have used spectroscopic methods to determine the zeta potential values. The EE (%) assay was carried out in dialysis bags and the brilliant red probe was used to determine CE (%) due to its property of forming molecular complexes with CH. The graphic analysis of the effects allowed the identification of the main formulation and technological factors by the analysis of the selected responses and permitted the determination of the proper level of these factors for the response improvement. Moreover, fractional design allowed quantifying the interactions between the factors, which will consider in next experiments. The results obtained pointed out that LID amount was the predominant factor that increased the drug entrapment capacity (EE). The CE (%) response was mainly affected by the concentration of the CH solution and the stirring rate, although all the interactions between the main factors have statistical significance.

Quantifying the Clinical Significance of Cannabis Withdrawal

Science.gov (United States)

Allsop, David J.; Copeland, Jan; Norberg, Melissa M.; Fu, Shanlin; Molnar, Anna; Lewis, John; Budney, Alan J.

2012-01-01

Background and Aims Questions over the clinical significance of cannabis withdrawal have hindered its inclusion as a discrete cannabis induced psychiatric condition in the Diagnostic and Statistical Manual of Mental Disorders (DSM IV). This study aims to quantify functional impairment to normal daily activities from cannabis withdrawal, and looks at the factors predicting functional impairment. In addition the study tests the influence of functional impairment from cannabis withdrawal on cannabis use during and after an abstinence attempt. Methods and Results A volunteer sample of 49 non-treatment seeking cannabis users who met DSM-IV criteria for dependence provided daily withdrawal-related functional impairment scores during a one-week baseline phase and two weeks of monitored abstinence from cannabis with a one month follow up. Functional impairment from withdrawal symptoms was strongly associated with symptom severity (p = 0.0001). Participants with more severe cannabis dependence before the abstinence attempt reported greater functional impairment from cannabis withdrawal (p = 0.03). Relapse to cannabis use during the abstinence period was associated with greater functional impairment from a subset of withdrawal symptoms in high dependence users. Higher levels of functional impairment during the abstinence attempt predicted higher levels of cannabis use at one month follow up (p = 0.001). Conclusions Cannabis withdrawal is clinically significant because it is associated with functional impairment to normal daily activities, as well as relapse to cannabis use. Sample size in the relapse group was small and the use of a non-treatment seeking population requires findings to be replicated in clinical samples. Tailoring treatments to target withdrawal symptoms contributing to functional impairment during a quit attempt may improve treatment outcomes. PMID:23049760

Quantifying the clinical significance of cannabis withdrawal.

Directory of Open Access Journals (Sweden)

David J Allsop

Full Text Available Questions over the clinical significance of cannabis withdrawal have hindered its inclusion as a discrete cannabis induced psychiatric condition in the Diagnostic and Statistical Manual of Mental Disorders (DSM IV. This study aims to quantify functional impairment to normal daily activities from cannabis withdrawal, and looks at the factors predicting functional impairment. In addition the study tests the influence of functional impairment from cannabis withdrawal on cannabis use during and after an abstinence attempt.A volunteer sample of 49 non-treatment seeking cannabis users who met DSM-IV criteria for dependence provided daily withdrawal-related functional impairment scores during a one-week baseline phase and two weeks of monitored abstinence from cannabis with a one month follow up. Functional impairment from withdrawal symptoms was strongly associated with symptom severity (p=0.0001. Participants with more severe cannabis dependence before the abstinence attempt reported greater functional impairment from cannabis withdrawal (p=0.03. Relapse to cannabis use during the abstinence period was associated with greater functional impairment from a subset of withdrawal symptoms in high dependence users. Higher levels of functional impairment during the abstinence attempt predicted higher levels of cannabis use at one month follow up (p=0.001.Cannabis withdrawal is clinically significant because it is associated with functional impairment to normal daily activities, as well as relapse to cannabis use. Sample size in the relapse group was small and the use of a non-treatment seeking population requires findings to be replicated in clinical samples. Tailoring treatments to target withdrawal symptoms contributing to functional impairment during a quit attempt may improve treatment outcomes.

Using the Statistical Indicators for the General Insurances Activity

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Ion Partachi

2007-04-01

Full Text Available The statistics of the general insurances activity is largely used in the actuarial calculations. The actuarial analysis are achieved exclusively on the basis of primary and derived indicators, which are drawn up by various statistical methods. The statistical indicators which are used in this respect are obtained on the basis of the factors and conditions allowing the compensation cases to occur.The actuarial analysis is performed over the time as well, by using the chronological which allow the decomposition of the phenomenon being studied by its factors of influence.In this article, after briefly presenting a number of point of view regarding the utilization of the statistical indicators in the actuarial analysis, we have analyzed, successively, a series of issues, such as: the statistical indicators as regards the general insurances fund forming, expressed in physical and value units, or as absolute, relative and average volumes; the statistical indicators of the utilization of the general insurances funds (with the same diversified form of expression and the statistical indicators of the outcomes of the general insurances activity.A particular accent went to the underlying of certain methodological aspects regarding the calculation of the above mentioned indicators, emphasizing certain particular characteristics concerning their utilization in the frame of the actuarial analysis.The article is stressing the clarification of the fact that these indicators are used in the actuarial analysis as a real system. The respective proportions are enumerated, by underlying the concrete possibilities of computation, which secure the possibility of performing the necessary analysis involved by a decisional process.

New robust statistical procedures for the polytomous logistic regression models.

Science.gov (United States)

Castilla, Elena; Ghosh, Abhik; Martin, Nirian; Pardo, Leandro

2018-05-17

This article derives a new family of estimators, namely the minimum density power divergence estimators, as a robust generalization of the maximum likelihood estimator for the polytomous logistic regression model. Based on these estimators, a family of Wald-type test statistics for linear hypotheses is introduced. Robustness properties of both the proposed estimators and the test statistics are theoretically studied through the classical influence function analysis. Appropriate real life examples are presented to justify the requirement of suitable robust statistical procedures in place of the likelihood based inference for the polytomous logistic regression model. The validity of the theoretical results established in the article are further confirmed empirically through suitable simulation studies. Finally, an approach for the data-driven selection of the robustness tuning parameter is proposed with empirical justifications. © 2018, The International Biometric Society.

Understanding Statistics and Statistics Education: A Chinese Perspective

Science.gov (United States)

Shi, Ning-Zhong; He, Xuming; Tao, Jian

2009-01-01

In recent years, statistics education in China has made great strides. However, there still exists a fairly large gap with the advanced levels of statistics education in more developed countries. In this paper, we identify some existing problems in statistics education in Chinese schools and make some proposals as to how they may be overcome. We…

Investigating spousal concordance of diabetes through statistical analysis and data mining.

Directory of Open Access Journals (Sweden)

Jong-Yi Wang

Full Text Available Spousal clustering of diabetes merits attention. Whether old-age vulnerability or a shared family environment determines the concordance of diabetes is also uncertain. This study investigated the spousal concordance of diabetes and compared the risk of diabetes concordance between couples and noncouples by using nationally representative data.A total of 22,572 individuals identified from the 2002-2013 National Health Insurance Research Database of Taiwan constituted 5,643 couples and 5,643 noncouples through 1:1 dual propensity score matching (PSM. Factors associated with concordance in both spouses with diabetes were analyzed at the individual level. The risk of diabetes concordance between couples and noncouples was compared at the couple level. Logistic regression was the main statistical method. Statistical data were analyzed using SAS 9.4. C&RT and Apriori of data mining conducted in IBM SPSS Modeler 13 served as a supplement to statistics.High odds of the spousal concordance of diabetes were associated with old age, middle levels of urbanization, and high comorbidities (all P < 0.05. The dual PSM analysis revealed that the risk of diabetes concordance was significantly higher in couples (5.19% than in noncouples (0.09%; OR = 61.743, P < 0.0001.A high concordance rate of diabetes in couples may indicate the influences of assortative mating and shared environment. Diabetes in a spouse implicates its risk in the partner. Family-based diabetes care that emphasizes the screening of couples at risk of diabetes by using the identified risk factors is suggested in prospective clinical practice interventions.

Mathematical statistics

CERN Document Server

Pestman, Wiebe R

2009-01-01

This textbook provides a broad and solid introduction to mathematical statistics, including the classical subjects hypothesis testing, normal regression analysis, and normal analysis of variance. In addition, non-parametric statistics and vectorial statistics are considered, as well as applications of stochastic analysis in modern statistics, e.g., Kolmogorov-Smirnov testing, smoothing techniques, robustness and density estimation. For students with some elementary mathematical background. With many exercises. Prerequisites from measure theory and linear algebra are presented.

Evaluating statistical and clinical significance of intervention effects in single-case experimental designs: An SPSS method to analyze univariate data

NARCIS (Netherlands)

Maric, M.; de Haan, M.; Hogendoorn, S.M.; Wolters, L.H.; Huizenga, H.M.

2015-01-01

Single-case experimental designs are useful methods in clinical research practice to investigate individual client progress. Their proliferation might have been hampered by methodological challenges such as the difficulty applying existing statistical procedures. In this article, we describe a

Evaluating statistical and clinical significance of intervention effects in single-case experimental designs: an SPSS method to analyze univariate data

NARCIS (Netherlands)

Maric, Marija; de Haan, Else; Hogendoorn, Sanne M.; Wolters, Lidewij H.; Huizenga, Hilde M.

2015-01-01

Single-case experimental designs are useful methods in clinical research practice to investigate individual client progress. Their proliferation might have been hampered by methodological challenges such as the difficulty applying existing statistical procedures. In this article, we describe a

Statistical inference and visualization in scale-space for spatially dependent images

KAUST Repository

Vaughan, Amy

2012-03-01

SiZer (SIgnificant ZERo crossing of the derivatives) is a graphical scale-space visualization tool that allows for statistical inferences. In this paper we develop a spatial SiZer for finding significant features and conducting goodness-of-fit tests for spatially dependent images. The spatial SiZer utilizes a family of kernel estimates of the image and provides not only exploratory data analysis but also statistical inference with spatial correlation taken into account. It is also capable of comparing the observed image with a specific null model being tested by adjusting the statistical inference using an assumed covariance structure. Pixel locations having statistically significant differences between the image and a given null model are highlighted by arrows. The spatial SiZer is compared with the existing independent SiZer via the analysis of simulated data with and without signal on both planar and spherical domains. We apply the spatial SiZer method to the decadal temperature change over some regions of the Earth. © 2011 The Korean Statistical Society.

Statistical methods for quantitative indicators of impacts, applied to transmission line projects

International Nuclear Information System (INIS)

Ospina Norena, Jesus Efren; Lema Tapias, Alvaro de Jesus

2005-01-01

Multivariate statistical analyses are proposed for encountering the relationships between variables and impacts, to obtain high explanatory power for interpretation of the causes and effects and achieve the highest certainty possible, to evaluate and classify impacts by their level of influence

The Role of Statistics in Business and Industry

CERN Document Server

Hahn, Gerald J

2011-01-01

An insightful guide to the use of statistics for solving key problems in modern-day business and industry This book has been awarded the Technometrics Ziegel Prize for the best book reviewed by the journal in 2010. Technometrics is a journal of statistics for the physical, chemical and engineering sciences, published jointly by the American Society for Quality and the American Statistical Association. Criteria for the award include that the book brings together in one volume a body of material previously only available in scattered research articles and having the potential to significantly im

Statistical analysis of the influence of lancing on the secondary corrosion affecting SG tube ends in the CP0 series of PWRs

International Nuclear Information System (INIS)

Souchois, T.

1995-05-01

The main method of tube sheet cleaning during unit outages is high pressure lancing. A new tool called CECIL has been in use for this purpose since 1991 on the CP0 series of PWRs. This paper presents a statistical analysis of inspection data providing a basis for determining whether the type of lancing tool used has a 'statistically' significant effect, on the one hand, on the progression of the secondary corrosion affecting the CP0 type PWR SG tube ends and, on the other hand, on the appearance of corrosion on sound tubes after one operating cycle. The study results showed the CECIL cleaning method to be more efficient in tat larger amounts of accumulated deposits were removed and the risks of early corrosion were 14 times lower, with slower degradation in the course of subsequent cycles. (author). 2 refs., 8 figs., 19 tabs

Sampling, Probability Models and Statistical Reasoning Statistical

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 5. Sampling, Probability Models and Statistical Reasoning Statistical Inference. Mohan Delampady V R Padmawar. General Article Volume 1 Issue 5 May 1996 pp 49-58 ...

Statistical Symbolic Execution with Informed Sampling

Science.gov (United States)

Filieri, Antonio; Pasareanu, Corina S.; Visser, Willem; Geldenhuys, Jaco

2014-01-01

Symbolic execution techniques have been proposed recently for the probabilistic analysis of programs. These techniques seek to quantify the likelihood of reaching program events of interest, e.g., assert violations. They have many promising applications but have scalability issues due to high computational demand. To address this challenge, we propose a statistical symbolic execution technique that performs Monte Carlo sampling of the symbolic program paths and uses the obtained information for Bayesian estimation and hypothesis testing with respect to the probability of reaching the target events. To speed up the convergence of the statistical analysis, we propose Informed Sampling, an iterative symbolic execution that first explores the paths that have high statistical significance, prunes them from the state space and guides the execution towards less likely paths. The technique combines Bayesian estimation with a partial exact analysis for the pruned paths leading to provably improved convergence of the statistical analysis. We have implemented statistical symbolic execution with in- formed sampling in the Symbolic PathFinder tool. We show experimentally that the informed sampling obtains more precise results and converges faster than a purely statistical analysis and may also be more efficient than an exact symbolic analysis. When the latter does not terminate symbolic execution with informed sampling can give meaningful results under the same time and memory limits.

Statistical shape analysis with applications in R

CERN Document Server

Dryden, Ian L

2016-01-01

A thoroughly revised and updated edition of this introduction to modern statistical methods for shape analysis Shape analysis is an important tool in the many disciplines where objects are compared using geometrical features. Examples include comparing brain shape in schizophrenia; investigating protein molecules in bioinformatics; and describing growth of organisms in biology. This book is a significant update of the highly-regarded `Statistical Shape Analysis’ by the same authors. The new edition lays the foundations of landmark shape analysis, including geometrical concepts and statistical techniques, and extends to include analysis of curves, surfaces, images and other types of object data. Key definitions and concepts are discussed throughout, and the relative merits of different approaches are presented. The authors have included substantial new material on recent statistical developments and offer numerous examples throughout the text. Concepts are introduced in an accessible manner, while reta...

The census categorization of ethnic identity: Between theoretical comprehensions and statistical practice

Directory of Open Access Journals (Sweden)

Knežević Aleksandar

2016-01-01

Full Text Available Theoretical debates about ethnic identity during the second half of the 20th century did not just attract attention of academic circles, but they influenced creation of political discourse which determined public life in almost every multinational society, regardless the level of socio-economic development. In recent decades, many theories about ethnic identity have emerged, especially those about ethnicity as a relatively new concept, which caused a great deal of controversy that has been ongoing since the 1960s. Modern demography deals with problems of great social importance, especially when it comes to anthropological, social and political demography, whose results often take lead in the modern political debate. In that sense, a lot of theoretical approaches tried to emphasize the decline of importance of traditional elements of ethnic identity, even their disappearance in favor of supranational concepts, over the past more than half a century. However, in practice, the opposite processes are constantly repeating and the awareness of belonging to certain ethnic group, not only remained the important part of social life, but its significance rapidly grew in certain periods and societies. Ethnic and social pluralism of modern societies, together with massive migration flows, have initiated the review of sustainability, not only the traditional definitions of ethnic identity, but also the various supranational concepts which have mostly emerged from ethnic identification and legal nationality. The fear that ethno-cultural pluralism will have negative effects on ethno-demographic differentiation increased the need for quantitative researches of demographic characteristics of population towards ethnic marks, also for reviewing of methodological solutions of ethno-statistic evidence, starting from definitions, categorizations and statistic classification, as far as the ways of collecting and publishing the data. In that sense the censuses are

Statistics

International Nuclear Information System (INIS)

2005-01-01

For the years 2004 and 2005 the figures shown in the tables of Energy Review are partly preliminary. The annual statistics published in Energy Review are presented in more detail in a publication called Energy Statistics that comes out yearly. Energy Statistics also includes historical time-series over a longer period of time (see e.g. Energy Statistics, Statistics Finland, Helsinki 2004.) The applied energy units and conversion coefficients are shown in the back cover of the Review. Explanatory notes to the statistical tables can be found after tables and figures. The figures presents: Changes in GDP, energy consumption and electricity consumption, Carbon dioxide emissions from fossile fuels use, Coal consumption, Consumption of natural gas, Peat consumption, Domestic oil deliveries, Import prices of oil, Consumer prices of principal oil products, Fuel prices in heat production, Fuel prices in electricity production, Price of electricity by type of consumer, Average monthly spot prices at the Nord pool power exchange, Total energy consumption by source and CO 2 -emissions, Supplies and total consumption of electricity GWh, Energy imports by country of origin in January-June 2003, Energy exports by recipient country in January-June 2003, Consumer prices of liquid fuels, Consumer prices of hard coal, natural gas and indigenous fuels, Price of natural gas by type of consumer, Price of electricity by type of consumer, Price of district heating by type of consumer, Excise taxes, value added taxes and fiscal charges and fees included in consumer prices of some energy sources and Energy taxes, precautionary stock fees and oil pollution fees

Frog Statistics

Science.gov (United States)

Whole Frog Project and Virtual Frog Dissection Statistics wwwstats output for January 1 through duplicate or extraneous accesses. For example, in these statistics, while a POST requesting an image is as well. Note that this under-represents the bytes requested. Starting date for following statistics

Teaching biology through statistics: application of statistical methods in genetics and zoology courses.

Science.gov (United States)

Colon-Berlingeri, Migdalisel; Burrowes, Patricia A

2011-01-01

Incorporation of mathematics into biology curricula is critical to underscore for undergraduate students the relevance of mathematics to most fields of biology and the usefulness of developing quantitative process skills demanded in modern biology. At our institution, we have made significant changes to better integrate mathematics into the undergraduate biology curriculum. The curricular revision included changes in the suggested course sequence, addition of statistics and precalculus as prerequisites to core science courses, and incorporating interdisciplinary (math-biology) learning activities in genetics and zoology courses. In this article, we describe the activities developed for these two courses and the assessment tools used to measure the learning that took place with respect to biology and statistics. We distinguished the effectiveness of these learning opportunities in helping students improve their understanding of the math and statistical concepts addressed and, more importantly, their ability to apply them to solve a biological problem. We also identified areas that need emphasis in both biology and mathematics courses. In light of our observations, we recommend best practices that biology and mathematics academic departments can implement to train undergraduates for the demands of modern biology.

Influence of self-esteem and negative affectivity on oral health related quality of life in patients with partial tooth loss

DEFF Research Database (Denmark)

Øzhayat, Esben Boeskov

2013-01-01

NA would be associated with worse OHRQoL.Methods: OHRQoL measured by the Oral Health Impact Profile 49 (OHIP-49), self-esteem measured by the Rosenberg Self-Esteem Scale (RSES), NA measured by the Eysenck Personality Inventory Questionnaire (EPI-Q), global oral rating of oral comfort and controlling......To meaningfully interpret oral health-related quality of life (OHRQoL) measures, the influence of personality traits must be investigated. Objectives:To investigate and quantify the influence of self-esteem and negative affectivity (NA) on OHRQoL. It was hypothesized that low self-esteem and high...... and clinically significantly higher and self-esteem was statistically significantly lower in patients reporting worse oral comfort. Conclusion: NA had the strongest and most clinically meaningful influence, but both NA and self-esteem was found to influence OHRQoL; low self-esteem and high NA was associated...

Intimate partner violence influence on deliveries assisted by skilled health personnel.

Science.gov (United States)

Refaat, Amany

2013-01-01

Millennium Development Goal 5 calls for increasing proportions of deliveries assisted by skilled health personnel to reduce maternal mortality. This study aims to identifying the implication of exposure to intimate partner violence on these proportions. This study used domestic violence modules data of Demographic and Health Surveys of six countries from 2005 to 2007. Proportions of assisted deliveries were examined by sociodemographic characteristics and exposure to intimate partner violence in the studied countries. Influence on the proportion was examined against exposure to intimate partner violence through odds ratio and 95% of logistic regression analysis after controlling for women age, residence (urban/rural), household wealth level, economic level of country, educational level and working status of women and their husbands/partners. Data sets of 18,507 participants over 20 years of age showed that almost three-quarters (73%) of women had deliveries assisted by skilled health personnel. One-third of the women were ever exposed to intimate partner violence (37%) and 9% of them to the severe level. Exposure to intimate partner violence statistically significantly lowered this proportion to 69% (odds ratio: 0.73; 95% confidence interval: 0.67-0.78) meanwhile severe violence lowered it to 65% (odds ratio 0.64; 95% confidence interval: 0.58-0.72). When running multiple regression analysis, exposure to intimate partner violence retained its statistically significant decreasing influence on proportions and was not biased by the other stronger socioeconomic characteristics. Intimate partner violence has an independent influence on reducing assisted deliveries by skilled health personnel. Programs working for increasing proportions of assisted deliveries by skilled health personnel are recommended to integrate protection women from violence.

Statistical learning and selective inference.

Science.gov (United States)

Taylor, Jonathan; Tibshirani, Robert J

2015-06-23

We describe the problem of "selective inference." This addresses the following challenge: Having mined a set of data to find potential associations, how do we properly assess the strength of these associations? The fact that we have "cherry-picked"--searched for the strongest associations--means that we must set a higher bar for declaring significant the associations that we see. This challenge becomes more important in the era of big data and complex statistical modeling. The cherry tree (dataset) can be very large and the tools for cherry picking (statistical learning methods) are now very sophisticated. We describe some recent new developments in selective inference and illustrate their use in forward stepwise regression, the lasso, and principal components analysis.

Significance of Perceived Social Expectation and Implications to Conservation Education: Turtle Conservation as a Case Study

Science.gov (United States)

Lo, Alex Y.; Chow, Alex T.; Cheung, Sze Man

2012-11-01

The likelihood of participating in wildlife conservation programs is dependent on social influences and circumstances. This view is validated by a case study of behavioral intention to support conservation of Asian turtles. A total of 776 college students in China completed a questionnaire survey designed to identify factors associated with their intention to support conservation. A regression model explained 48 % of variance in the level of intention. Perceived social expectation was the strongest predictor, followed by attitudes toward turtle protection and perceived behavioral control, altogether explaining 44 %. Strong ethics and socio-economic variables had some statistical significant impacts and accounted for 3 % of the variance. The effects of general environmental awareness, trust and responsibility ascription were modest. Knowledge about turtles was a weak predictor. We conclude that perceived social expectation is a limiting factor of conservation behavior. Sustained interest and commitment to conservation can be created by enhancing positive social influences. Conservation educators should explore the potential of professionally supported, group-based actions that can nurture a sense of collective achievement as part of an educational campaign.

The influence of journal submission guidelines on authors' reporting of statistics and use of open research practices.

Science.gov (United States)

Giofrè, David; Cumming, Geoff; Fresc, Luca; Boedker, Ingrid; Tressoldi, Patrizio

2017-01-01

From January 2014, Psychological Science introduced new submission guidelines that encouraged the use of effect sizes, estimation, and meta-analysis (the "new statistics"), required extra detail of methods, and offered badges for use of open science practices. We investigated the use of these practices in empirical articles published by Psychological Science and, for comparison, by the Journal of Experimental Psychology: General, during the period of January 2013 to December 2015. The use of null hypothesis significance testing (NHST) was extremely high at all times and in both journals. In Psychological Science, the use of confidence intervals increased markedly overall, from 28% of articles in 2013 to 70% in 2015, as did the availability of open data (3 to 39%) and open materials (7 to 31%). The other journal showed smaller or much smaller changes. Our findings suggest that journal-specific submission guidelines may encourage desirable changes in authors' practices.

Statistical reporting inconsistencies in experimental philosophy.

Science.gov (United States)

Colombo, Matteo; Duev, Georgi; Nuijten, Michèle B; Sprenger, Jan

2018-01-01

Experimental philosophy (x-phi) is a young field of research in the intersection of philosophy and psychology. It aims to make progress on philosophical questions by using experimental methods traditionally associated with the psychological and behavioral sciences, such as null hypothesis significance testing (NHST). Motivated by recent discussions about a methodological crisis in the behavioral sciences, questions have been raised about the methodological standards of x-phi. Here, we focus on one aspect of this question, namely the rate of inconsistencies in statistical reporting. Previous research has examined the extent to which published articles in psychology and other behavioral sciences present statistical inconsistencies in reporting the results of NHST. In this study, we used the R package statcheck to detect statistical inconsistencies in x-phi, and compared rates of inconsistencies in psychology and philosophy. We found that rates of inconsistencies in x-phi are lower than in the psychological and behavioral sciences. From the point of view of statistical reporting consistency, x-phi seems to do no worse, and perhaps even better, than psychological science.

Statistical reporting inconsistencies in experimental philosophy

Science.gov (United States)

Colombo, Matteo; Duev, Georgi; Nuijten, Michèle B.; Sprenger, Jan

2018-01-01

Experimental philosophy (x-phi) is a young field of research in the intersection of philosophy and psychology. It aims to make progress on philosophical questions by using experimental methods traditionally associated with the psychological and behavioral sciences, such as null hypothesis significance testing (NHST). Motivated by recent discussions about a methodological crisis in the behavioral sciences, questions have been raised about the methodological standards of x-phi. Here, we focus on one aspect of this question, namely the rate of inconsistencies in statistical reporting. Previous research has examined the extent to which published articles in psychology and other behavioral sciences present statistical inconsistencies in reporting the results of NHST. In this study, we used the R package statcheck to detect statistical inconsistencies in x-phi, and compared rates of inconsistencies in psychology and philosophy. We found that rates of inconsistencies in x-phi are lower than in the psychological and behavioral sciences. From the point of view of statistical reporting consistency, x-phi seems to do no worse, and perhaps even better, than psychological science. PMID:29649220

Statistical Analysis of Big Data on Pharmacogenomics

Science.gov (United States)

Fan, Jianqing; Liu, Han

2013-01-01

This paper discusses statistical methods for estimating complex correlation structure from large pharmacogenomic datasets. We selectively review several prominent statistical methods for estimating large covariance matrix for understanding correlation structure, inverse covariance matrix for network modeling, large-scale simultaneous tests for selecting significantly differently expressed genes and proteins and genetic markers for complex diseases, and high dimensional variable selection for identifying important molecules for understanding molecule mechanisms in pharmacogenomics. Their applications to gene network estimation and biomarker selection are used to illustrate the methodological power. Several new challenges of Big data analysis, including complex data distribution, missing data, measurement error, spurious correlation, endogeneity, and the need for robust statistical methods, are also discussed. PMID:23602905

Familiar units prevail over statistical cues in word segmentation.

Science.gov (United States)

Poulin-Charronnat, Bénédicte; Perruchet, Pierre; Tillmann, Barbara; Peereman, Ronald

2017-09-01

In language acquisition research, the prevailing position is that listeners exploit statistical cues, in particular transitional probabilities between syllables, to discover words of a language. However, other cues are also involved in word discovery. Assessing the weight learners give to these different cues leads to a better understanding of the processes underlying speech segmentation. The present study evaluated whether adult learners preferentially used known units or statistical cues for segmenting continuous speech. Before the exposure phase, participants were familiarized with part-words of a three-word artificial language. This design allowed the dissociation of the influence of statistical cues and familiar units, with statistical cues favoring word segmentation and familiar units favoring (nonoptimal) part-word segmentation. In Experiment 1, performance in a two-alternative forced choice (2AFC) task between words and part-words revealed part-word segmentation (even though part-words were less cohesive in terms of transitional probabilities and less frequent than words). By contrast, an unfamiliarized group exhibited word segmentation, as usually observed in standard conditions. Experiment 2 used a syllable-detection task to remove the likely contamination of performance by memory and strategy effects in the 2AFC task. Overall, the results suggest that familiar units overrode statistical cues, ultimately questioning the need for computation mechanisms of transitional probabilities (TPs) in natural language speech segmentation.

Analysis of statistical misconception in terms of statistical reasoning

Science.gov (United States)

Maryati, I.; Priatna, N.

2018-05-01

Reasoning skill is needed for everyone to face globalization era, because every person have to be able to manage and use information from all over the world which can be obtained easily. Statistical reasoning skill is the ability to collect, group, process, interpret, and draw conclusion of information. Developing this skill can be done through various levels of education. However, the skill is low because many people assume that statistics is just the ability to count and using formulas and so do students. Students still have negative attitude toward course which is related to research. The purpose of this research is analyzing students’ misconception in descriptive statistic course toward the statistical reasoning skill. The observation was done by analyzing the misconception test result and statistical reasoning skill test; observing the students’ misconception effect toward statistical reasoning skill. The sample of this research was 32 students of math education department who had taken descriptive statistic course. The mean value of misconception test was 49,7 and standard deviation was 10,6 whereas the mean value of statistical reasoning skill test was 51,8 and standard deviation was 8,5. If the minimal value is 65 to state the standard achievement of a course competence, students’ mean value is lower than the standard competence. The result of students’ misconception study emphasized on which sub discussion that should be considered. Based on the assessment result, it was found that students’ misconception happen on this: 1) writing mathematical sentence and symbol well, 2) understanding basic definitions, 3) determining concept that will be used in solving problem. In statistical reasoning skill, the assessment was done to measure reasoning from: 1) data, 2) representation, 3) statistic format, 4) probability, 5) sample, and 6) association.

Statistical Inference at Work: Statistical Process Control as an Example

Science.gov (United States)

Bakker, Arthur; Kent, Phillip; Derry, Jan; Noss, Richard; Hoyles, Celia

2008-01-01

To characterise statistical inference in the workplace this paper compares a prototypical type of statistical inference at work, statistical process control (SPC), with a type of statistical inference that is better known in educational settings, hypothesis testing. Although there are some similarities between the reasoning structure involved in…

What can we learn from noise? - Mesoscopic nonequilibrium statistical physics.

Science.gov (United States)

Kobayashi, Kensuke

2016-01-01

Mesoscopic systems - small electric circuits working in quantum regime - offer us a unique experimental stage to explorer quantum transport in a tunable and precise way. The purpose of this Review is to show how they can contribute to statistical physics. We introduce the significance of fluctuation, or equivalently noise, as noise measurement enables us to address the fundamental aspects of a physical system. The significance of the fluctuation theorem (FT) in statistical physics is noted. We explain what information can be deduced from the current noise measurement in mesoscopic systems. As an important application of the noise measurement to statistical physics, we describe our experimental work on the current and current noise in an electron interferometer, which is the first experimental test of FT in quantum regime. Our attempt will shed new light in the research field of mesoscopic quantum statistical physics.

Influence of Thunderstorms on the Structure of the Ionosphere using Composite Analysis

Science.gov (United States)

Nava, O.; Sutherland, E.

2017-12-01

It is well known in the amateur (ham) radio community that thunderstorms have a significant influence on local and long-distance high-frequency (HF) communications. This study aims to characterize the structure of the ionosphere in response to strong convective activity and cloud electrification. Superposed Epoch Analysis is applied to surface weather observations and ionosonde data at Eglin Air Force Base, Florida from August 2014 to July 2017. Preliminary results indicate that thunderstorms significantly modify the structure of the ionosphere, generating statistically different measurements of several key parameters (e.g., foEs, hmF2, ITEC) compared to clear-sky observations. Seasonal and diurnal influences between the thunderstorm and clear sky cases are also explored. Accurate characterization of the ionosphere in response to thunderstorms has important implications for the effective use of HF communications in civilian and military operations, to include emergency services, aviation, amateur radio, and over-the-horizon radar.

Fast recognition of single molecules based on single-event photon statistics

International Nuclear Information System (INIS)

Dong Shuangli; Huang Tao; Liu Yuan; Wang Jun; Zhang Guofeng; Xiao Liantuan; Jia Suotang

2007-01-01

Mandel's Q parameter, which is determined from single-event photon statistics, provides an alternative way to recognize single molecules with fluorescence detection, other than the second-order correlation function. It is shown that the Q parameter of an assumed ideal double-molecule fluorescence with the same average photon number as that of the sample fluorescence can act as the criterion for single-molecule recognition. The influence of signal-to-background ratio and the error estimates for photon statistics are also presented. We have applied this method to ascertain single Cy5 dye molecules within hundreds of milliseconds

The extraction and integration framework: a two-process account of statistical learning.

Science.gov (United States)

Thiessen, Erik D; Kronstein, Alexandra T; Hufnagle, Daniel G

2013-07-01

The term statistical learning in infancy research originally referred to sensitivity to transitional probabilities. Subsequent research has demonstrated that statistical learning contributes to infant development in a wide array of domains. The range of statistical learning phenomena necessitates a broader view of the processes underlying statistical learning. Learners are sensitive to a much wider range of statistical information than the conditional relations indexed by transitional probabilities, including distributional and cue-based statistics. We propose a novel framework that unifies learning about all of these kinds of statistical structure. From our perspective, learning about conditional relations outputs discrete representations (such as words). Integration across these discrete representations yields sensitivity to cues and distributional information. To achieve sensitivity to all of these kinds of statistical structure, our framework combines processes that extract segments of the input with processes that compare across these extracted items. In this framework, the items extracted from the input serve as exemplars in long-term memory. The similarity structure of those exemplars in long-term memory leads to the discovery of cues and categorical structure, which guides subsequent extraction. The extraction and integration framework provides a way to explain sensitivity to both conditional statistical structure (such as transitional probabilities) and distributional statistical structure (such as item frequency and variability), and also a framework for thinking about how these different aspects of statistical learning influence each other. 2013 APA, all rights reserved

Influence of Compacting Rate on the Properties of Compressed Earth Blocks

Directory of Open Access Journals (Sweden)

Humphrey Danso

2016-01-01

Full Text Available Compaction of blocks contributes significantly to the strength properties of compressed earth blocks. This paper investigates the influence of compacting rates on the properties of compressed earth blocks. Experiments were conducted to determine the density, compressive strength, splitting tensile strength, and erosion properties of compressed earth blocks produced with different rates of compacting speed. The study concludes that although the low rate of compaction achieved slightly better performance characteristics, there is no statistically significant difference between the soil blocks produced with low compacting rate and high compacting rate. The study demonstrates that there is not much influence on the properties of compressed earth blocks produced with low and high compacting rates. It was further found that there are strong linear correlations between the compressive strength test and density, and density and the erosion. However, a weak linear correlation was found between tensile strength and compressive strength, and tensile strength and density.

A Statistical Primer: Understanding Descriptive and Inferential Statistics

OpenAIRE

Gillian Byrne

2007-01-01

As libraries and librarians move more towards evidence‐based decision making, the data being generated in libraries is growing. Understanding the basics of statistical analysis is crucial for evidence‐based practice (EBP), in order to correctly design and analyze researchas well as to evaluate the research of others. This article covers the fundamentals of descriptive and inferential statistics, from hypothesis construction to sampling to common statistical techniques including chi‐square, co...

Solution of the statistical bootstrap with Bose statistics

International Nuclear Information System (INIS)

Engels, J.; Fabricius, K.; Schilling, K.

1977-01-01

A brief and transparent way to introduce Bose statistics into the statistical bootstrap of Hagedorn and Frautschi is presented. The resulting bootstrap equation is solved by a cluster expansion for the grand canonical partition function. The shift of the ultimate temperature due to Bose statistics is determined through an iteration process. We discuss two-particle spectra of the decaying fireball (with given mass) as obtained from its grand microcanonical level density

Non-statistical behavior of coupled optical systems

International Nuclear Information System (INIS)

Perez, G.; Pando Lambruschini, C.; Sinha, S.; Cerdeira, H.A.

1991-10-01

We study globally coupled chaotic maps modeling an optical system, and find clear evidence of non-statistical behavior: the mean square deviation (MSD) of the mean field saturates with respect to increase in the number of elements coupled, after a critical value, and its distribution is clearly non-Gaussian. We also find that the power spectrum of the mean field displays well defined peaks, indicating a subtle coherence among different elements, even in the ''turbulent'' phase. This system is a physically realistic model that may be experimentally realizable. It is also a higher dimensional example (as each individual element is given by a complex map). Its study confirms that the phenomena observed in a wide class of coupled one-dimensional maps are present here as well. This gives more evidence to believe that such non-statistical behavior is probably generic in globally coupled systems. We also investigate the influence of parametric fluctuations on the MSD. (author). 10 refs, 7 figs, 1 tab

Pointwise probability reinforcements for robust statistical inference.

Science.gov (United States)