10 CFR 51.32 - Finding of no significant impact.

Science.gov (United States)

2010-01-01

... assessment is included, the finding need not repeat any of the discussion in the assessment but may... 10 Energy 2 2010-01-01 2010-01-01 false Finding of no significant impact. 51.32 Section 51.32... Section 102(2) Finding of No Significant Impact § 51.32 Finding of no significant impact. (a) A finding of...

Swiss solar power statistics 2007 - Significant expansion

International Nuclear Information System (INIS)

Hostettler, T.

2008-01-01

This article presents and discusses the 2007 statistics for solar power in Switzerland. A significant number of new installations is noted as is the high production figures from newer installations. The basics behind the compilation of the Swiss solar power statistics are briefly reviewed and an overview for the period 1989 to 2007 is presented which includes figures on the number of photovoltaic plant in service and installed peak power. Typical production figures in kilowatt-hours (kWh) per installed kilowatt-peak power (kWp) are presented and discussed for installations of various sizes. Increased production after inverter replacement in older installations is noted. Finally, the general political situation in Switzerland as far as solar power is concerned are briefly discussed as are international developments.

Test for the statistical significance of differences between ROC curves

International Nuclear Information System (INIS)

Metz, C.E.; Kronman, H.B.

1979-01-01

A test for the statistical significance of observed differences between two measured Receiver Operating Characteristic (ROC) curves has been designed and evaluated. The set of observer response data for each ROC curve is assumed to be independent and to arise from a ROC curve having a form which, in the absence of statistical fluctuations in the response data, graphs as a straight line on double normal-deviate axes. To test the significance of an apparent difference between two measured ROC curves, maximum likelihood estimates of the two parameters of each curve and the associated parameter variances and covariance are calculated from the corresponding set of observer response data. An approximate Chi-square statistic with two degrees of freedom is then constructed from the differences between the parameters estimated for each ROC curve and from the variances and covariances of these estimates. This statistic is known to be truly Chi-square distributed only in the limit of large numbers of trials in the observer performance experiments. Performance of the statistic for data arising from a limited number of experimental trials was evaluated. Independent sets of rating scale data arising from the same underlying ROC curve were paired, and the fraction of differences found (falsely) significant was compared to the significance level, α, used with the test. Although test performance was found to be somewhat dependent on both the number of trials in the data and the position of the underlying ROC curve in the ROC space, the results for various significance levels showed the test to be reliable under practical experimental conditions

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.

On detection and assessment of statistical significance of Genomic Islands

Directory of Open Access Journals (Sweden)

Chaudhuri Probal

2008-04-01

Full Text Available Abstract Background Many of the available methods for detecting Genomic Islands (GIs in prokaryotic genomes use markers such as transposons, proximal tRNAs, flanking repeats etc., or they use other supervised techniques requiring training datasets. Most of these methods are primarily based on the biases in GC content or codon and amino acid usage of the islands. However, these methods either do not use any formal statistical test of significance or use statistical tests for which the critical values and the P-values are not adequately justified. We propose a method, which is unsupervised in nature and uses Monte-Carlo statistical tests based on randomly selected segments of a chromosome. Such tests are supported by precise statistical distribution theory, and consequently, the resulting P-values are quite reliable for making the decision. Results Our algorithm (named Design-Island, an acronym for Detection of Statistically Significant Genomic Island runs in two phases. Some 'putative GIs' are identified in the first phase, and those are refined into smaller segments containing horizontally acquired genes in the refinement phase. This method is applied to Salmonella typhi CT18 genome leading to the discovery of several new pathogenicity, antibiotic resistance and metabolic islands that were missed by earlier methods. Many of these islands contain mobile genetic elements like phage-mediated genes, transposons, integrase and IS elements confirming their horizontal acquirement. Conclusion The proposed method is based on statistical tests supported by precise distribution theory and reliable P-values along with a technique for visualizing statistically significant islands. The performance of our method is better than many other well known methods in terms of their sensitivity and accuracy, and in terms of specificity, it is comparable to other methods.

Increasing the statistical significance of entanglement detection in experiments.

Science.gov (United States)

Jungnitsch, Bastian; Niekamp, Sönke; Kleinmann, Matthias; Gühne, Otfried; Lu, He; Gao, Wei-Bo; Chen, Yu-Ao; Chen, Zeng-Bing; Pan, Jian-Wei

2010-05-28

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. Experimentally, we observe this phenomenon in a four-photon experiment, testing the Mermin and Ardehali inequality for different levels of noise. Furthermore, we provide a way to develop entanglement tests with high statistical significance.

Testing the Difference of Correlated Agreement Coefficients for Statistical Significance

Science.gov (United States)

Gwet, Kilem L.

2016-01-01

This article addresses the problem of testing the difference between two correlated agreement coefficients for statistical significance. A number of authors have proposed methods for testing the difference between two correlated kappa coefficients, which require either the use of resampling methods or the use of advanced statistical modeling…

Network Expansion and Pathway Enrichment Analysis towards Biologically Significant Findings from Microarrays

Directory of Open Access Journals (Sweden)

Wu Xiaogang

2012-06-01

Full Text Available In many cases, crucial genes show relatively slight changes between groups of samples (e.g. normal vs. disease, and many genes selected from microarray differential analysis by measuring the expression level statistically are also poorly annotated and lack of biological significance. In this paper, we present an innovative approach - network expansion and pathway enrichment analysis (NEPEA for integrative microarray analysis. We assume that organized knowledge will help microarray data analysis in significant ways, and the organized knowledge could be represented as molecular interaction networks or biological pathways. Based on this hypothesis, we develop the NEPEA framework based on network expansion from the human annotated and predicted protein interaction (HAPPI database, and pathway enrichment from the human pathway database (HPD. We use a recently-published microarray dataset (GSE24215 related to insulin resistance and type 2 diabetes (T2D as case study, since this study provided a thorough experimental validation for both genes and pathways identified computationally from classical microarray analysis and pathway analysis. We perform our NEPEA analysis for this dataset based on the results from the classical microarray analysis to identify biologically significant genes and pathways. Our findings are not only consistent with the original findings mostly, but also obtained more supports from other literatures.

42 CFR 417.806 - Financial records, statistical data, and cost finding.

Science.gov (United States)

2010-10-01

... 42 Public Health 3 2010-10-01 2010-10-01 false Financial records, statistical data, and cost... MEDICAL PLANS, AND HEALTH CARE PREPAYMENT PLANS Health Care Prepayment Plans § 417.806 Financial records, statistical data, and cost finding. (a) The principles specified in § 417.568 apply to HCPPs, except those in...

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.

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…

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

Significant events in psychotherapy: An update of research findings.

Science.gov (United States)

Timulak, Ladislav

2010-11-01

Significant events research represents a specific approach to studying client-identified important moments in the therapy process. The current study provides an overview of the significant events research conducted, the methodology used together with findings and implications. PsychInfo database was searched with keywords such as significant events, important events, significant moments, important moments, and counselling or psychotherapy. The references of the selected studies were also searched. This process led to the identification of 41 primary studies that used client-identified significant event(s) as a main or secondary focus of the study. These were consequently reviewed with regard to their methodology and findings. The findings are presented according to type of study conducted. The impacts of helpful events reported by clients are focused on contributions to therapeutic relationship and to in-session outcomes. Hindering events focus on some client disappointment with the therapist or therapy. The group therapy modality highlighted additional helpful impacts (like learning from others). Perspectives on what is significant in therapy differ between clients and therapists. The intensive qualitative studies reviewed confirm that the processes involved in significant events are complex and ambiguous. Studies show that the helpful events may also contain many hindering elements and that specific events are deeply contextually embedded in the preceding events of therapy. Some studies suggest that helpful significant events are therapeutically productive although this may need to be established further. Specific intensive studies show that the clients' perceptions in therapy may differ dramatically from that of the therapist. Furthermore, the relational and emotional aspects of significant moments may be more important for the clients than the cognitive aspects of therapy which are frequently stressed by therapists. 2010 The British Psychological Society.

40 CFR 1508.13 - Finding of no significant impact.

Science.gov (United States)

2010-07-01

... note any other environmental documents related to it (§ 1501.7(a)(5)). If the assessment is included, the finding need not repeat any of the discussion in the assessment but may incorporate it by... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Finding of no significant impact. 1508...

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…

"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...

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 ...

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…

Frequency and clinical significance of CAT findings in purulent and lymphocytic meningitis

International Nuclear Information System (INIS)

Schneider, E.; Kloes, G.; Hopp, G.; Becker, H.

1982-01-01

From 1974-1980, computerized tomography was carried out on 34 patients with purulent and on 17 patients with lymphocytic meningitis. 25 out of the patients with purulent meningitis resp. meningoencephalitis could be examined in the acute stage. For all patients with already attenuated clinical symptoms normal results were obtained, while for the remainder findings were in part highly pathological consisting, e.g. in dilatations or narviowings of the ventricula system, failure to make the outer liquor cavities roentgenoparens, accumulation of pas in the subarachnoidal and subdur spaces including the interhemispheric clefs, cerebral medulla and periventricular edemas, abscesses and signs of ependymitis. Various findings could only be classified as pathological upon serial examination. Correlation statistics showed that all patients with marked pathological CT findings also suffered from distinct pertubations of consciousness. Out of 14 patients with pathological CT findings, 12 died. No connexions could be established between the level of liquor cell counts and CT alterations. Among 17 patients with a lymphocytic meningitis, CT findings were pathological with a mean dilatation of the ventricular system in only one case of chronic course and predominantly basal localization. The patient decreased. Phathological CT findings in purulent and lymphocytic meningitis point to an unfavourable prognosis. (orig.) [de

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.

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...

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.

Prevalence and clinical significance of extravascular incidental findings in patients undergoing CT cervico-cerebral angiography

International Nuclear Information System (INIS)

Crockett, Matthew Thomas; Murphy, Blathnaid; Smith, Jennifer; Kavanagh, Eoin Carl

2015-01-01

Highlights: • CT cervico-cerebral angiography (CTCCA) is a commonly performed study for assessment of vascular pathologies of head and neck. • This study assessed the prevalence, clinical significance and management of extravascular incidental findings detected on CTCCA. • This study demonstrated the presence of clinically significant incidental findings in 14% of patients undergoing CTCCA with 8% of these findings deemed to be highly significant. 19% of patients with highly clinically significant findings did not receive appropriate follow up. • A standardised method of reporting incidental findings, such as that used in this paper is suggested to aid radiologists and referring physicians in recording and communicating these findings. - Abstract: Introduction: CT cervico-cerebral angiography (CTCCA) is now the first line diagnostic imaging modality for the majority of vascular pathologies of the head and neck with diagnostic value comparable to or better than traditional angiographic techniques. The aim of this study was to assess the prevalence, clinical significance and management of extravascular incidental findings detected on CTCCA. Materials and methods: A retrospective review of the CTCCA reports of 302 consecutive patients from 2009 to 2013 was undertaken. Extravascular incidental findings were classified, according to an adaptation of the CT colonography data and reporting system (CRADS), as EV1–EV4. EV1 = no incidental findings, EV2 = clinically insignificant incidental finding, EV3 = incidental finding of intermediate clinical significance, EV4 = highly clinically significant finding. Follow up of the electronic medical records of patients with EV3 or EV4 findings was undertaken to determine subsequent management. Results: Potentially clinically significant findings were demonstrated in 14.2% of patients with 8.6% of patients having a highly clinically significant finding. 4 incidental findings were confirmed to be malignant lesions and 5

Finding the Root Causes of Statistical Inconsistency in Community Earth System Model Output

Science.gov (United States)

Milroy, D.; Hammerling, D.; Baker, A. H.

2017-12-01

Baker et al (2015) developed the Community Earth System Model Ensemble Consistency Test (CESM-ECT) to provide a metric for software quality assurance by determining statistical consistency between an ensemble of CESM outputs and new test runs. The test has proved useful for detecting statistical difference caused by compiler bugs and errors in physical modules. However, detection is only the necessary first step in finding the causes of statistical difference. The CESM is a vastly complex model comprised of millions of lines of code which is developed and maintained by a large community of software engineers and scientists. Any root cause analysis is correspondingly challenging. We propose a new capability for CESM-ECT: identifying the sections of code that cause statistical distinguishability. The first step is to discover CESM variables that cause CESM-ECT to classify new runs as statistically distinct, which we achieve via Randomized Logistic Regression. Next we use a tool developed to identify CESM components that define or compute the variables found in the first step. Finally, we employ the application Kernel GENerator (KGEN) created in Kim et al (2016) to detect fine-grained floating point differences. We demonstrate an example of the procedure and advance a plan to automate this process in our future work.

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.

Recent Literature on Whether Statistical Significance Tests Should or Should Not Be Banned.

Science.gov (United States)

Deegear, James

This paper summarizes the literature regarding statistical significant testing with an emphasis on recent literature in various discipline and literature exploring why researchers have demonstrably failed to be influenced by the American Psychological Association publication manual's encouragement to report effect sizes. Also considered are…

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.

Environmental assessments and findings of no significant impact--FDA. Notice.

Science.gov (United States)

1998-05-18

The Food and Drug Administration (FDA) is announcing that it has reviewed environmental assessments (EA's) and issued findings of no significant impact (FONSI's) relating to the 167 new drug applications (NDA's) and supplemental applications listed in this document. FDA is publishing this notice because Federal regulations require public notice of the availability of environmental documents.

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

Science.gov (United States)

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.

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

7 CFR Exhibit I to Subpart G of... - Finding of No Significant Environmental Impact

Science.gov (United States)

2010-01-01

... 7 Agriculture 13 2010-01-01 2009-01-01 true Finding of No Significant Environmental Impact I... Environmental Impact SUBJECT: Finding of No Significant Environmental Impact and Necessary Environmental... human environment. Therefore, the preparation of an environmental impact statement is not necessary. I...

Meta-analyses triggered by previous (false-)significant findings : Problems and solutions

NARCIS (Netherlands)

Schuit, Ewoud; Roes, Kit C B; Mol, Ben W J; Kwee, Anneke; Moons, Karel G M; Groenwold, Rolf H H

2015-01-01

BACKGROUND: Meta-analyses are typically triggered by a (potentially false-significant) finding in one of the preceding primary studies. We studied consequences of meta-analysis investigating effects when primary studies that triggered such meta-analysis are also included. METHODS: We analytically

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.

78 FR 75370 - Draft Supplemental Environmental Assessment and Finding of No Significant Impact for Flood...

Science.gov (United States)

2013-12-11

... Environmental Assessment and Finding of No Significant Impact for Flood Control Improvements to the Rio Grande... Supplemental Environmental Assessment (SEA) and Finding of No Significant Impact (FONSI). SUMMARY: Pursuant to... Significant Impact for Flood Control Improvements to the Rio Grande Canalization Project in Vado, New Mexico...

75 FR 12581 - Notice of Availability of Environmental Assessment and Finding of No Significant Impact for...

Science.gov (United States)

2010-03-16

... Environmental Assessment and Finding of No Significant Impact for Exemption From 10 CFR 30, 40, and 70... Assessment and Finding of No Significant Impact for Exemption from Commencement of Construction Requirements... has reached a Finding of No Significant Impact. II. Summary of the Environmental Assessment Background...

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...

Necrotizing pneumonia: CT findings and its clinical significance

International Nuclear Information System (INIS)

Park, Hong Suk; Im, Jung Gi; Ryoo, Jae Wook; Yeon, Kyung Mo; Han, Man Chung

1995-01-01

To analyze CT and follow-up chest radiographic findings in patients with necrotizing pneumonia and to evaluate clinical significance of the extent of necrosis. We reviewed medical records and retrospectively analysed CT scans and follow-up chest radiographs of 22 patients with necrotizing pneumonia, confirmed by biopsy (n = 7) and culture (n = 15). Inclusion criteria for necrotizing pneumonia was necrotic low attenuation, with or without cavitation on postcontrast enhanced CT scan. The study group included 15 men and seven women, aged 11-66 years (average: 47 years). The pathogens of necrotizing pneumonia were Klebsiella spp (n = 7), Enterobacter spp (n = 5), Actinomyces spp (n = 4), Pseudomonas spp (n = 4), Nocardia spp (n = 4), and others (n = 5). Average duration of pneumonia was 4.1 months. On CT scan, pneumonic consolidations were well-marginated in 14 patients and there were cavities on initial CT scan in 16 cases. Margins of the necrotic portion on CT scan were well-demarcated in majority of the patients (16/22). Low attenuation areas on initial CT scan resulted in cavitation, fibrosis and volume loss as shown on follow-up chest radiographs. The larger the necrotic areas on CT, the more the volume loss was. CT findings of necrotizing pneumonia were well-marginated air-space consolidation with low attenuation area, with or without cavity. The extent of necrotic area was closely related with the degree of fibrotic change later on. CT is important tool for diagnosis and prediction of parenchymal damage in necrotizing pneumonia

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

Directory of Open Access Journals (Sweden)

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.

Audit of radiology communication systems for critical, urgent, and unexpected significant findings

International Nuclear Information System (INIS)

Duncan, K.A.; Drinkwater, K.J.; Dugar, N.; Howlett, D.C.

2016-01-01

Aim: To determine the compliance of UK radiology departments and trusts/healthcare organisations with National Patient Safety Agency and Royal College of Radiologist's published guidance on the communication of critical, urgent, and unexpected significant radiological findings. Materials and methods: A questionnaire was sent to all UK radiology department audit leads asking for details of their current departmental policy regarding the issuing of alerts; use of automated electronic alert systems; methods of notification of clinicians of critical, urgent, and unexpected significant radiological findings; monitoring of results receipt; and examples of the more common types of serious pathologies for which alerts were issued. Results: One hundred and fifty-four of 229 departments (67%) responded. Eighty-eight percent indicated that they had a policy in place for the communication of critical, urgent, and unexpected significant radiological findings. Only 34% had an automated electronic alert system in place and only 17% had a facility for service-wide electronic tracking of radiology reports. In only 11 departments with an electronic acknowledgement system was someone regularly monitoring the read rate. Conclusion: There is wide variation in practice across the UK with regard to the communication and monitoring of reports with many departments/trusts not fully compliant with published UK guidance. Despite the widespread use of electronic systems, only a minority of departments/trusts have and use electronic tracking to ensure reports have been read and acted upon. - Highlights: • UK wide audit of communication of significant radiology results. • 88% of departments have a communication policy in place. • 34% of departments have an automated electronic alert system. • 17% of Trusts have facility for service wide electronic tracking of radiology reports.

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.

Audit of radiology communication systems for critical, urgent, and unexpected significant findings.

Science.gov (United States)

Duncan, K A; Drinkwater, K J; Dugar, N; Howlett, D C

2016-03-01

To determine the compliance of UK radiology departments and trusts/healthcare organisations with National Patient Safety Agency and Royal College of Radiologist's published guidance on the communication of critical, urgent, and unexpected significant radiological findings. A questionnaire was sent to all UK radiology department audit leads asking for details of their current departmental policy regarding the issuing of alerts; use of automated electronic alert systems; methods of notification of clinicians of critical, urgent, and unexpected significant radiological findings; monitoring of results receipt; and examples of the more common types of serious pathologies for which alerts were issued. One hundred and fifty-four of 229 departments (67%) responded. Eighty-eight percent indicated that they had a policy in place for the communication of critical, urgent, and unexpected significant radiological findings. Only 34% had an automated electronic alert system in place and only 17% had a facility for service-wide electronic tracking of radiology reports. In only 11 departments with an electronic acknowledgement system was someone regularly monitoring the read rate. There is wide variation in practice across the UK with regard to the communication and monitoring of reports with many departments/trusts not fully compliant with published UK guidance. Despite the widespread use of electronic systems, only a minority of departments/trusts have and use electronic tracking to ensure reports have been read and acted upon. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

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.

Communication of Unexpected and Significant Findings on Chest Radiographs With an Automated PACS Alert System.

LENUS (Irish Health Repository)

Hayes, Sara A

2014-08-01

An integral part of realizing the enormous potential of imaging in patient care is close communication between radiologists and referring physicians. One key element of this process is the communication of unexpected significant findings. The authors examined the performance of a PACS-based alert system in the appropriate communication of reports containing unexpected significant findings to referring physicians.

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.

Science.gov (United States)

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....

The Thurgood Marshall School of Law Empirical Findings: A Report of the Statistical Analysis of the July 2010 TMSL Texas Bar Results

Science.gov (United States)

Kadhi, Tau; Holley, D.

2010-01-01

The following report gives the statistical findings of the July 2010 TMSL Bar results. Procedures: Data is pre-existing and was given to the Evaluator by email from the Registrar and Dean. Statistical analyses were run using SPSS 17 to address the following research questions: 1. What are the statistical descriptors of the July 2010 overall TMSL…

The Thurgood Marshall School of Law Empirical Findings: A Report of the Statistical Analysis of the February 2010 TMSL Texas Bar Results

Science.gov (United States)

Kadhi, T.; Holley, D.; Rudley, D.; Garrison, P.; Green, T.

2010-01-01

The following report gives the statistical findings of the 2010 Thurgood Marshall School of Law (TMSL) Texas Bar results. This data was pre-existing and was given to the Evaluator by email from the Dean. Then, in-depth statistical analyses were run using the SPSS 17 to address the following questions: 1. What are the statistical descriptors of the…

Finding differentially expressed genes in high dimensional data: Rank based test statistic via a distance measure.

Science.gov (United States)

Mathur, Sunil; Sadana, Ajit

2015-12-01

We present a rank-based test statistic for the identification of differentially expressed genes using a distance measure. The proposed test statistic is highly robust against extreme values and does not assume the distribution of parent population. Simulation studies show that the proposed test is more powerful than some of the commonly used methods, such as paired t-test, Wilcoxon signed rank test, and significance analysis of microarray (SAM) under certain non-normal distributions. The asymptotic distribution of the test statistic, and the p-value function are discussed. The application of proposed method is shown using a real-life data set. © The Author(s) 2011.

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

Head multidetector computed tomography: emergency medicine physicians overestimate the pretest probability and legal risk of significant findings.

Science.gov (United States)

Baskerville, Jerry Ray; Herrick, John

2012-02-01

This study focuses on clinically assigned prospective estimated pretest probability and pretest perception of legal risk as independent variables in the ordering of multidetector computed tomographic (MDCT) head scans. Our primary aim is to measure the association between pretest probability of a significant finding and pretest perception of legal risk. Secondarily, we measure the percentage of MDCT scans that physicians would not order if there was no legal risk. This study is a prospective, cross-sectional, descriptive analysis of patients 18 years and older for whom emergency medicine physicians ordered a head MDCT. We collected a sample of 138 patients subjected to head MDCT scans. The prevalence of a significant finding in our population was 6%, yet the pretest probability expectation of a significant finding was 33%. The legal risk presumed was even more dramatic at 54%. These data support the hypothesis that physicians presume the legal risk to be significantly higher than the risk of a significant finding. A total of 21% or 15% patients (95% confidence interval, ±5.9%) would not have been subjected to MDCT if there was no legal risk. Physicians overestimated the probability that the computed tomographic scan would yield a significant result and indicated an even greater perceived medicolegal risk if the scan was not obtained. Physician test-ordering behavior is complex, and our study queries pertinent aspects of MDCT testing. The magnification of legal risk vs the pretest probability of a significant finding is demonstrated. Physicians significantly overestimated pretest probability of a significant finding on head MDCT scans and presumed legal risk. Copyright © 2012 Elsevier Inc. All rights reserved.

Chest CT findings of toxocariasis: Correlation with laboratory results

International Nuclear Information System (INIS)

Hur, J.H.; Lee, I.J.; Kim, J.-H.; Kim, D.-G.; Hwang, H.J.; Koh, S.H.; Lee, K.

2014-01-01

Aim: To assess the relationship between chest computed tomography (CT) findings of patients with toxocariasis and levels of serological markers. Materials and methods: A total of 38 cases of patients diagnosed with toxocariasis by enzyme-linked immunosorbent assay (ELISA), CT, and serological markers were retrospectively reviewed. The presence of nodule with or without ground-glass opacity (GGO) halo, consolidation, focal GGO, pleural effusion, and lymphadenopathy at chest CT were evaluated. Statistical analysis was performed with the Fisher's exact test. Results: The most common chest CT findings were nodule (n = 12, 31.6%) and focal GGO (n = 12, 31.6%). In patients with normal eosinophil levels, focal GGO (n = 9, 37.5%) was the most common finding. In contrast, nodule with a GGO halo (n = 7, 50%) was the most common finding in the eosinophilia group. Nodule with a GGO halo was more common in the eosinophilia group, with a statistically significant difference (p = 0.017). Nodule was more common in the eosinophilia group, and focal GGO was more common in the normal eosinophil group. Conclusion: The most common chest CT findings in toxocariasis were nodule with or without GGO halo, and focal GGO. In the eosinophilia group, nodule with a GGO halo was significantly more frequent. Other CT findings did not show a statistically significant relationship with serological markers

Quick Access: Find Statistical Data on the Internet.

Science.gov (United States)

Su, Di

1999-01-01

Provides an annotated list of Internet sources (World Wide Web, ftp, and gopher sites) for current and historical statistical business data, including selected interest rates, the Consumer Price Index, the Producer Price Index, foreign currency exchange rates, noon buying rates, per diem rates, the special drawing right, stock quotes, and mutual…

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)

Contrast-enhanced dynamic magnetic resonance imaging findings of hepatocellular carcinoma and their correlation with histopathologic findings

Energy Technology Data Exchange (ETDEWEB)

Karahan, Okkes I. [Department of Radiology, Erciyes University Medical Faculty, PK: 18 Talas 38280, Kayseri (Turkey)]. E-mail: oikarahan@yahoo.com; Yikilmaz, Ali [Department of Radiology, Erciyes University Medical Faculty, PK: 18 Talas 38280, Kayseri (Turkey); Artis, Tarik [Department of General Surgery, Erciyes University Medical Faculty, PK: 18 Talas 38280, Kayseri (Turkey); Canoz, Ozlem [Department of Pathology, Erciyes University Medical Faculty, PK: 18 Talas 38280, Kayseri (Turkey); Coskun, Abdulhakim [Department of Radiology, Erciyes University Medical Faculty, PK: 18 Talas 38280, Kayseri (Turkey); Torun, Edip [Department of Internal Medicine, Division of Gastrenterology, Erciyes University Medical Faculty, PK: 18 Talas 38280, Kayseri (Turkey)

2006-03-15

Purpose: To investigate the correlations of contrast-enhanced magnetic resonance (MR) imaging findings of large (>5 cm) hepatocellular carcinomas with tumor size and histopathologic findings. Materials and methods: MR imaging was performed in 30 patients with a histopathologic diagnosis of hepatocellular carcinoma. The imaging protocol included non-contrast, hepatic arterial, portal venous and late phases. The signal intensities relative to the liver, enhancement patterns and the morphologic features of the lesions were evaluated in relation to size and degree of differentiation. Results: On histopathologic examination, 12 of 30 (40%) tumors were well-differentiated (grade 1), 6 of 30 (20%) were moderately differentiated (grades 2 and 3) and 12 of 30 (40%) were poorly differentiated (grade 4). Tumor size, tumor boundary, serum alpha-fetoprotein level and portal vein invasion were found to have statistically significant correlations with the degree of differentiation (p < 0.05). Portal vein invasion, capsule formation and tumor surface characteristics showed statistically significant correlations with tumor size (p < 0.05). Conclusion: MR imaging findings of hepatocellular carcinomas larger than 5 cm are partially dependent on tumor size and degree of differentiation.

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.

Finding significantly connected voxels based on histograms of connection strengths

DEFF Research Database (Denmark)

Kasenburg, Niklas; Pedersen, Morten Vester; Darkner, Sune

2016-01-01

We explore a new approach for structural connectivity based segmentations of subcortical brain regions. Connectivity based segmentations are usually based on fibre connections from a seed region to predefined target regions. We present a method for finding significantly connected voxels based...... on the distribution of connection strengths. Paths from seed voxels to all voxels in a target region are obtained from a shortest-path tractography. For each seed voxel we approximate the distribution with a histogram of path scores. We hypothesise that the majority of estimated connections are false-positives...... and that their connection strength is distributed differently from true-positive connections. Therefore, an empirical null-distribution is defined for each target region as the average normalized histogram over all voxels in the seed region. Single histograms are then tested against the corresponding null...

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.

A novel statistic for genome-wide interaction analysis.

Directory of Open Access Journals (Sweden)

Xuesen Wu

2010-09-01

Full Text Available Although great progress in genome-wide association studies (GWAS has been made, the significant SNP associations identified by GWAS account for only a few percent of the genetic variance, leading many to question where and how we can find the missing heritability. There is increasing interest in genome-wide interaction analysis as a possible source of finding heritability unexplained by current GWAS. However, the existing statistics for testing interaction have low power for genome-wide interaction analysis. To meet challenges raised by genome-wide interactional analysis, we have developed a novel statistic for testing interaction between two loci (either linked or unlinked. The null distribution and the type I error rates of the new statistic for testing interaction are validated using simulations. Extensive power studies show that the developed statistic has much higher power to detect interaction than classical logistic regression. The results identified 44 and 211 pairs of SNPs showing significant evidence of interactions with FDR<0.001 and 0.001finding remaining missing heritability unexplained by the current GWAS, and the developed novel statistic is able to search significant interaction between SNPs across the genome. Real data analysis showed that the results of genome-wide interaction analysis can be replicated in two independent studies.

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

The clinical significance of equivocal findings on spinal MRI in children with medulloblastoma.

Science.gov (United States)

Bennett, Julie; Ashmawy, Ramy; Ramaswamy, Vijay; Stephens, Derek; Bouffet, Eric; Laperriere, Normand; Taylor, Michael; Shroff, Manohar; Bartels, Ute

2017-08-01

Medulloblastoma (MB) is the most common malignant brain tumor of childhood, with cerebrospinal fluid spread the most common site of metastasis. Currently, children diagnosed with MB and evidence of spinal metastasis are treated with an increased dose of craniospinal radiation (CSI). This report reviewed equivocal abnormalities including nerve root clumping, linear vascular enhancement, nerve root enhancement and/or other vague findings on spinal magnetic resonance imaging (MRI) to elucidate their prognostic significance and aid in risk stratification. This retrospective cohort study identified children (≥3 years) diagnosed with MB between 1988 and 2012. Children treated with upfront CSI were included, and staging spine MRI must have been done preoperatively or within 72 hr of primary tumor resection. Initial MRI of the spine was assessed by two independent reviewers blinded to outcome to evaluate for equivocal findings. Survival analysis was done to determine impact on prognosis. One hundred of 157 patients were eligible for the analysis. Equivocal findings were identified in 48 (48%) patients, with MRI done preoperatively in 45 (94%) patients. Analysis by subgroup identified a higher proportion of equivocal findings in the sonic hedgehog (SHH) subgroup (P = 0.007). Five-year overall survival (OS) in children with equivocal findings compared to those with normal MRI was not different, 80 vs. 84.8% respectively, while OS in M3 patients was worse at 54.7% (P = 0.02). A higher proportion of equivocal findings was identified in the SHH subgroup. This institutional retrospective review demonstrates equivocal findings are common, not associated with decreased OS and should not prompt increased dose of CSI. © 2017 Wiley Periodicals, Inc.

MR findings of tuberculous arthritis; significance of tuberculoma

International Nuclear Information System (INIS)

Jang, Han Won; Kim, Jeen Woo; Cho, Kil Ho

2001-01-01

To determine the magnetic resonance (MR) imaging findings of tuberculous arthritis, and the frequency-in such cases-with which tuberculoma occurs. MR images of 26 patients (M;F, 14;12: mean age, 46.2 years) with pathologically proven tuberculous arthritis were retrospectively reviewed. The presence of joint effusion, subchondral erosion, synovial proliferation and soft tissue abscess, and whether the inner wall of this abscess was smooth, were assessed. In particular, we determined whether a nodular lesion which showed low SI on T1WI, central low SI with peripheral hjigh SI on T2WI, and rim enhancement on contrast study, was a tuberculoma. The joints involved were those of the knee (n=7), hip (n=7), shoulder (n=4), sacroiliac region (n=3), elbow (n=3), and ankle (n=2). Joint effusion was noted in 15 cases (58%), and subchondral erosion in 24 (92%). synovial proliferation was found in 23 cases (88%), and soft tissue abscess in 24 (92%). The inner wall of this abscess was irregular in 17 cases (71%). A tuberculoma was present in intra-or extra-or extra-articular soft tissue in 18 cases (69%). The MR findings of tuberculous arthritis were subchondral erosion, synovial proliferation, and soft tissue abscess. The presence of a tuberculoma in intra-or extra-articular soft tissue, a specific finding in tuberculous arthritis, was noted in 69% of our cases

MR findings of tuberculous arthritis; significance of tuberculoma

Energy Technology Data Exchange (ETDEWEB)

Jang, Han Won; Kim, Jeen Woo; Cho, Kil Ho [Yeungnam Univ. College of Medicine, Taegu (Korea, Republic of)

2001-02-01

To determine the magnetic resonance (MR) imaging findings of tuberculous arthritis, and the frequency-in such cases-with which tuberculoma occurs. MR images of 26 patients (M;F, 14;12: mean age, 46.2 years) with pathologically proven tuberculous arthritis were retrospectively reviewed. The presence of joint effusion, subchondral erosion, synovial proliferation and soft tissue abscess, and whether the inner wall of this abscess was smooth, were assessed. In particular, we determined whether a nodular lesion which showed low SI on T1WI, central low SI with peripheral hjigh SI on T2WI, and rim enhancement on contrast study, was a tuberculoma. The joints involved were those of the knee (n=7), hip (n=7), shoulder (n=4), sacroiliac region (n=3), elbow (n=3), and ankle (n=2). Joint effusion was noted in 15 cases (58%), and subchondral erosion in 24 (92%). synovial proliferation was found in 23 cases (88%), and soft tissue abscess in 24 (92%). The inner wall of this abscess was irregular in 17 cases (71%). A tuberculoma was present in intra-or extra-or extra-articular soft tissue in 18 cases (69%). The MR findings of tuberculous arthritis were subchondral erosion, synovial proliferation, and soft tissue abscess. The presence of a tuberculoma in intra-or extra-articular soft tissue, a specific finding in tuberculous arthritis, was noted in 69% of our cases.

The relationship between cerebral infarction on MR and angiographic findings in moyamoya disease: significance of the posterior circulation

Energy Technology Data Exchange (ETDEWEB)

Lee, Eun Ja; Song, Soon Young [College of Medicine, Kwangdong Univ., Koyang (Korea, Republic of); Yu, Won Jong; Jung, So Lyung; Chung, Bong Gak; Kag, Si Won [College of Medicine, The Catholic Univ. of Korea, Seoul (Korea, Republic of); Kim, Man Deuk [College of Medicine, Pochon CHA Univ., Pochon (Korea, Republic of)

2002-06-01

To investigate the relationship between changes in the posterior and anterior circulation, as seen at angiography, and the frequency and extent of cerebral infarction revealed by MR imaging in moyamoya disease. This study involved 34 patients (22 females and 12 males, aged 2-52 years) in whom cerebral angiography revealed the presence of moyamoya disease (bilateral; unilateral= 24:10; total hemispheres=58) and who also underwent brain MR imaging. To evaluate the angiographic findings, we applied each angiographic staging system to the anterior and posterior circulation. Leptomeningeal collateral circulation from the cortical branches of the posterior cerebral artery (PCA) was also assigned one of four grades. At MR imaging, areas of cerebral cortical or subcortical infarction in the hemisphere were divided into six zones. White matter and basal ganglionic infarction, ventricular dilatation, cortical atrophy, and hemorrhagic lesions were also evaluated. To demonstrate the statistical significance of the relationship between the angiographic and the MR findings, both the Mantel-Haenszel chi-square test for trend and the chi-square test were used. The degree of steno-occlusive PCA change correlated significantly with the internal carotid artery (ICA) stage (p<0.0001). As PCA stages advanced, the degree of leptomeningeal collaterals from the PCA decreased significantly (P<0.0001), but ICA stages were not significant (p>0.05). The prevalence of infarction showed significant correlation with the degree of steno-occlusive change in both the ICA and PCA. The degree of cerebral ischemia in moyamoya patients increased proportionally with the severity of PCA stenosis rather than with that of steno-occlusive lesins of the anterior circulation. Infarctions tended to be distributed in the anterior part of the hemisphere at PCA state I or II, while in more advanced PCA lesions, they were also found posteriorly, especially in the territories of the posterior middle cerebral artery

Potential errors and misuse of statistics in studies on leakage in endodontics.

Science.gov (United States)

Lucena, C; Lopez, J M; Pulgar, R; Abalos, C; Valderrama, M J

2013-04-01

To assess the quality of the statistical methodology used in studies of leakage in Endodontics, and to compare the results found using appropriate versus inappropriate inferential statistical methods. The search strategy used the descriptors 'root filling' 'microleakage', 'dye penetration', 'dye leakage', 'polymicrobial leakage' and 'fluid filtration' for the time interval 2001-2010 in journals within the categories 'Dentistry, Oral Surgery and Medicine' and 'Materials Science, Biomaterials' of the Journal Citation Report. All retrieved articles were reviewed to find potential pitfalls in statistical methodology that may be encountered during study design, data management or data analysis. The database included 209 papers. In all the studies reviewed, the statistical methods used were appropriate for the category attributed to the outcome variable, but in 41% of the cases, the chi-square test or parametric methods were inappropriately selected subsequently. In 2% of the papers, no statistical test was used. In 99% of cases, a statistically 'significant' or 'not significant' effect was reported as a main finding, whilst only 1% also presented an estimation of the magnitude of the effect. When the appropriate statistical methods were applied in the studies with originally inappropriate data analysis, the conclusions changed in 19% of the cases. Statistical deficiencies in leakage studies may affect their results and interpretation and might be one of the reasons for the poor agreement amongst the reported findings. Therefore, more effort should be made to standardize statistical methodology. © 2012 International Endodontic Journal.

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

Directory of Open Access Journals (Sweden)

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.

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...

Use of statistical analysis to validate ecogenotoxicology findings arising from various comet assay components.

Science.gov (United States)

Hussain, Bilal; Sultana, Tayyaba; Sultana, Salma; Al-Ghanim, Khalid Abdullah; Masoud, Muhammad Shahreef; Mahboob, Shahid

2018-04-01

Cirrhinus mrigala, Labeo rohita, and Catla catla are economically important fish for human consumption in Pakistan, but industrial and sewage pollution has drastically reduced their population in the River Chenab. Statistics are an important tool to analyze and interpret comet assay results. The specific aims of the study were to determine the DNA damage in Cirrhinus mrigala, Labeo rohita, and Catla catla due to chemical pollution and to assess the validity of statistical analyses to determine the viability of the comet assay for a possible use with these freshwater fish species as a good indicator of pollution load and habitat degradation. Comet assay results indicated a significant (P comet head diameter, comet tail length, and % DNA damage. Regression analysis and correlation matrices conducted among the parameters of the comet assay affirmed the precision and the legitimacy of the results. The present study, therefore, strongly recommends that genotoxicological studies conduct appropriate analysis of the various components of comet assays to offer better interpretation of the assay data.

Thyroiditis: Radioisotope Scan Findings and Clinical Significance

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Chae; Han, Duck Sup; Park, Jung Suck; Kim, Se Jong; Park, Byung Lan; Kim, Byoung Geun [Kwangju Christian Hospital, Kwangju (Korea, Republic of)

1991-07-15

We analyzed Radioisotope scan findings of 46 patients of thyroiditis which were proven pathologically at K.C.H. The results were as follows 1) 45 patients were female, one was male and average age of patients was 37 years old. 2) The lesion site was predominant in both lobe (67%) Hashimoto's thyroiditis showed enlarged thyroid (85%) with cold nodule (20%), diffuse decreased activity (10%), while subacute thyroiditis was presented absent activity (53%), poor visualization (20%) or cold nodule (7%). 4) Radioisotope scan was valuable in evaluating function of thyroid gland and detection of lesion but there was a limit of pathological nature.

Behavioral investment strategy matters: a statistical arbitrage approach

OpenAIRE

Sun, David; Tsai, Shih-Chuan; Wang, Wei

2011-01-01

In this study, we employ a statistical arbitrage approach to demonstrate that momentum investment strategy tend to work better in periods longer than six months, a result different from findings in past literature. Compared with standard parametric tests, the statistical arbitrage method produces more clearly that momentum strategies work only in longer formation and holding periods. Also they yield positive significant returns in an up market, but negative yet insignificant returns in a down...

Testing Significance Testing

Directory of Open Access Journals (Sweden)

Joachim I. Krueger

2018-04-01

Full Text Available The practice of Significance Testing (ST remains widespread in psychological science despite continual criticism of its flaws and abuses. Using simulation experiments, we address four concerns about ST and for two of these we compare ST’s performance with prominent alternatives. We find the following: First, the 'p' values delivered by ST predict the posterior probability of the tested hypothesis well under many research conditions. Second, low 'p' values support inductive inferences because they are most likely to occur when the tested hypothesis is false. Third, 'p' values track likelihood ratios without raising the uncertainties of relative inference. Fourth, 'p' values predict the replicability of research findings better than confidence intervals do. Given these results, we conclude that 'p' values may be used judiciously as a heuristic tool for inductive inference. Yet, 'p' values cannot bear the full burden of inference. We encourage researchers to be flexible in their selection and use of statistical methods.

Statistical comparison of leaching behavior of incineration bottom ash using seawater and deionized water: Significant findings based on several leaching methods.

Science.gov (United States)

Yin, Ke; Dou, Xiaomin; Ren, Fei; Chan, Wei-Ping; Chang, Victor Wei-Chung

2018-02-15

Bottom ashes generated from municipal solid waste incineration have gained increasing popularity as alternative construction materials, however, they contains elevated heavy metals posing a challenge for its free usage. Different leaching methods are developed to quantify leaching potential of incineration bottom ashes meanwhile guide its environmentally friendly application. Yet, there are diverse IBA applications while the in situ environment is always complicated, challenging its legislation. In this study, leaching tests were conveyed using batch and column leaching methods with seawater as opposed to deionized water, to unveil the metal leaching potential of IBA subjected to salty environment, which is commonly encountered when using IBA in land reclamation yet not well understood. Statistical analysis for different leaching methods suggested disparate performance between seawater and deionized water primarily ascribed to ionic strength. Impacts of leachant are metal-specific dependent on leaching methods and have a function of intrinsic characteristics of incineration bottom ashes. Leaching performances were further compared on additional perspectives, e.g. leaching approach and liquid to solid ratio, indicating sophisticated leaching potentials dominated by combined geochemistry. It is necessary to develop application-oriented leaching methods with corresponding leaching criteria to preclude discriminations between different applications, e.g., terrestrial applications vs. land reclamation. Copyright © 2017 Elsevier B.V. All rights reserved.

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

KAUST Repository

Vaughan, Amy; Jun, Mikyoung; Park, Cheolwoo

2012-01-01

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

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.

Interpreting Statistical Findings A Guide For Health Professionals And Students

CERN Document Server

Walker, Jan

2010-01-01

This book is aimed at those studying and working in the field of health care, including nurses and the professions allied to medicine, who have little prior knowledge of statistics but for whom critical review of research is an essential skill.

Os odontoideum: a significant radiographic finding

International Nuclear Information System (INIS)

Choit, Rachel L.; Reilly, Christopher W.; Jamieson, Douglas H.

2005-01-01

Os odontoideum can lead to instability of the atlantoaxial joint and places the spinal cord at significant risk for acute catastrophic events after minor trauma or chronic neurological change. We present two cases of os odontoideum in pediatric patients that were not appreciated at earlier remote imaging but were, in retrospect, detectable. One patient presented with an acute spinal cord injury. Incorporating assessment of dens integrity into the evaluation algorithm for all pediatric cervical spine studies should lead to early detection of os odontoideum lesions and allow referral to appropriate clinical spinal services for evaluation, surveillance and possible surgery to prevent future complications. (orig.)

Os odontoideum: a significant radiographic finding

Energy Technology Data Exchange (ETDEWEB)

Choit, Rachel L.; Reilly, Christopher W. [BC Children' s Hospital, Department of Orthopaedics, Vancouver, BC (Canada); Jamieson, Douglas H. [BC Children' s Hospital, Department of Radiology, Vancouver (Canada)

2005-08-01

Os odontoideum can lead to instability of the atlantoaxial joint and places the spinal cord at significant risk for acute catastrophic events after minor trauma or chronic neurological change. We present two cases of os odontoideum in pediatric patients that were not appreciated at earlier remote imaging but were, in retrospect, detectable. One patient presented with an acute spinal cord injury. Incorporating assessment of dens integrity into the evaluation algorithm for all pediatric cervical spine studies should lead to early detection of os odontoideum lesions and allow referral to appropriate clinical spinal services for evaluation, surveillance and possible surgery to prevent future complications. (orig.)

Common misconceptions about data analysis and statistics.

Science.gov (United States)

Motulsky, Harvey J

2014-11-01

Ideally, any experienced investigator with the right tools should be able to reproduce a finding published in a peer-reviewed biomedical science journal. In fact, the reproducibility of a large percentage of published findings has been questioned. Undoubtedly, there are many reasons for this, but one reason maybe that investigators fool themselves due to a poor understanding of statistical concepts. In particular, investigators often make these mistakes: 1. P-Hacking. This is when you reanalyze a data set in many different ways, or perhaps reanalyze with additional replicates, until you get the result you want. 2. Overemphasis on P values rather than on the actual size of the observed effect. 3. Overuse of statistical hypothesis testing, and being seduced by the word "significant". 4. Overreliance on standard errors, which are often misunderstood.

Common misconceptions about data analysis and statistics.

Science.gov (United States)

Motulsky, Harvey J

2015-02-01

Ideally, any experienced investigator with the right tools should be able to reproduce a finding published in a peer-reviewed biomedical science journal. In fact, the reproducibility of a large percentage of published findings has been questioned. Undoubtedly, there are many reasons for this, but one reason may be that investigators fool themselves due to a poor understanding of statistical concepts. In particular, investigators often make these mistakes: (1) P-Hacking. This is when you reanalyze a data set in many different ways, or perhaps reanalyze with additional replicates, until you get the result you want. (2) Overemphasis on P values rather than on the actual size of the observed effect. (3) Overuse of statistical hypothesis testing, and being seduced by the word "significant". (4) Overreliance on standard errors, which are often misunderstood.

Electromyographic Findings in Overt Hypothyroidism and Subclinical Hypothyroidism

Directory of Open Access Journals (Sweden)

Emel Oğuz Akarsu

2013-12-01

Full Text Available OBJECTIVE: Hypothyroidism may cause neurologic signs and symptoms as its effects neuromuscular system like many other systems. Subclinical hypothyroidism is the most common thyroid dysfuntion, it may cause neuromuscular signs and symptoms. In this retrospective study, it is aimed to compare neuromuscular symptoms and electromyographic (EMG manifestations between hypothyroid patients and control group with normal thyroid function and without a disease causing polyneuropathy. METHODS: 31 overt hypothyroidic, 139 subclinic hypothyroidic patients and 50 individuals with normal thyroid function, without a disease causing polyneuropathy, as control group whom made EMG for another reason were included to the study. Neuromuscular symptoms, neurological examination and electrophysiological findings was obtained from the patient records. RESULTS: In our study, we observed frequent neuromuscular complaints such as fatigue, morning stiffness, cramp, general pain and paresthesia in favor of both for overt and subclinic hypothyroidism. Carpal Tunnel Syndrom(CTS, was statistically higher in overt hypothyroidism group than control group. CTS was also observed higher in subclinic hypothyroidism group when compared with control group but it didn't reach to statistical significance. We did not detect polyneuropathy in any group. Motor nerve velocity and compound muscle action potential amplitudes were found to be statistically significant difference between hypothyroid ve control group. CONCLUSION: Since motor fibres' and neuromuscular area's being affected in hypothyroidism, which we interpret to happen due to basal metabolism's slowing down, can show a significant recovery after thyroid replacement therapy. We consider that, in further studies, comparison of electrophysiological findings after treatment with the findings of pre -treatment is necessary

Wave Mechanics or Wave Statistical Mechanics

International Nuclear Information System (INIS)

Qian Shangwu; Xu Laizi

2007-01-01

By comparison between equations of motion of geometrical optics and that of classical statistical mechanics, this paper finds that there should be an analogy between geometrical optics and classical statistical mechanics instead of geometrical mechanics and classical mechanics. Furthermore, by comparison between the classical limit of quantum mechanics and classical statistical mechanics, it finds that classical limit of quantum mechanics is classical statistical mechanics not classical mechanics, hence it demonstrates that quantum mechanics is a natural generalization of classical statistical mechanics instead of classical mechanics. Thence quantum mechanics in its true appearance is a wave statistical mechanics instead of a wave mechanics.

Statistical power and the Rorschach: 1975-1991.

Science.gov (United States)

Acklin, M W; McDowell, C J; Orndoff, S

1992-10-01

The Rorschach Inkblot Test has been the source of long-standing controversies as to its nature and its psychometric properties. Consistent with behavioral science research in general, the concept of statistical power has been entirely ignored by Rorschach researchers. The concept of power is introduced and discussed, and a power survey of the Rorschach literature published between 1975 and 1991 in the Journal of Personality Assessment, Journal of Consulting and Clinical Psychology, Journal of Abnormal Psychology, Journal of Clinical Psychology, Journal of Personality, Psychological Bulletin, American Journal of Psychiatry, and Journal of Personality and Social Psychology was undertaken. Power was calculated for 2,300 statistical tests in 158 journal articles. Power to detect small, medium, and large effect sizes was .13, .56, and .85, respectively. Similar to the findings in other power surveys conducted on behavioral science research, we concluded that Rorschach research is underpowered to detect the differences under investigation. This undoubtedly contributes to the inconsistency of research findings which has been a source of controversy and criticism over the decades. It appears that research conducted according to the Comprehensive System for the Rorschach is more powerful. Recommendations are offered for improving power and strengthening the design sensitivity of Rorschach research, including increasing sample sizes, use of parametric statistics, reduction of error variance, more accurate reporting of findings, and editorial policies reflecting concern about the magnitude of relationships beyond an exclusive focus on levels of statistical significance.

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.

The anterior tilt angle of the proximal tibia epiphyseal plate: a significant radiological finding in young children with trampoline fractures.

Science.gov (United States)

Stranzinger, Enno; Leidolt, Lars; Eich, Georg; Klimek, Peter Michael

2014-08-01

Evaluation of the anterior tilt angle of the proximal tibia epiphyseal plate in young children, which suffered a trampoline fracture in comparison with a normal population. 62 children (31 females, 31 males) between 2 and 5 years of age (average 2 years 11 months, standard deviation 11 months) with radiographs in two views of the tibia were included in this retrospective study. 25 children with proximal tibia fractures were injured with a history of jumping on a trampoline. All other causes for tibia fractures were excluded. A normal age-mapped control cohort of 37 children was compared. These children had neither evidence of a trampoline related injury nor a fracture of the tibia. The anterior tilt angle of the epiphyseal plate of the tibia was defined as an angle between the proximal tibia physis and the distal tibia physis on a lateral view. Two radiologists evaluated all radiographs for fractures and measured the anterior tilt angle in consensus. An unpaired Student's t-test was used for statistical analysis (SPSS). Original reports were reviewed and compared with the radiological findings and follow-up radiographs. In the normal control group, the average anterior tilt angle measured -3.2°, SD ± 2.8°. The children with trampoline fractures showed an anterior tilt of +4.4°, SD ± 2.9°. The difference was statistically significant, Ptrampoline. These fractures may be very subtle and difficult to detect on initial radiographs. Measurement of the anterior tilt angle of the proximal tibia epiphyseal plate on lateral radiographs is supportive for interpreting correctly trampoline fractures. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

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

Clinical significance of pneumatosis intestinalis - correlation of MDCT-findings with treatment and outcome

Energy Technology Data Exchange (ETDEWEB)

Treyaud, Marc-Olivier; Duran, Rafael; Knebel, Jean-Francois; Meuli, Reto A.; Schmidt, Sabine [Lausanne University Hospital, Department of Diagnostic and Interventional Radiology, Lausanne (Switzerland); Zins, Marc [Fondation Hopital St Joseph, Department of Radiology, Paris (France)

2017-01-15

To evaluate the clinical significance of pneumatosis intestinalis (PI) including the influence on treatment and outcome. Two radiologists jointly reviewed MDCT-examinations of 149 consecutive emergency patients (53 women, mean age 64, range 21-95) with PI of the stomach (n = 4), small (n = 68) and/or large bowel (n = 96). PI extension, distribution and possibly associated porto-mesenteric venous gas (PMVG) were correlated with other MDCT-findings, risk factors, clinical management, laboratory, histopathology, final diagnosis and outcome. The most frequent cause of PI was intestinal ischemia (n = 80,53.7 %), followed by infection (n = 18,12.1 %), obstructive (n = 12,8.1 %) and non-obstructive (n = 10,6.7 %) bowel dilatation, unknown aetiologies (n = 8,5.4 %), drugs (n = 8,5.4 %), inflammation (n = 7,4.7 %), and others (n = 6,4 %). Neither PI distribution nor extension significantly correlated with underlying ischemia. Overall mortality was 41.6 % (n = 62), mostly related to intestinal ischemia (p = 0.003). Associated PMVG significantly correlated with underlying ischemia (p = 0.009), as did the anatomical distribution of PMVG (p = 0.015). Decreased mural contrast-enhancement was the only other MDCT-feature significantly associated with ischemia (p p < 0.001). Elevated white blood count significantly correlated with ischemia (p = 0.03). In emergency patients, ischemia remains the most common aetiology of PI, showing the highest mortality. PI with associated PMVG is an alerting sign. PI together with decreased mural contrast-enhancement indicates underlying ischemia. (orig.)

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.

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

Alcohol Facts and Statistics

Science.gov (United States)

... Standard Drink? Drinking Levels Defined Alcohol Facts and Statistics Print version Alcohol Use in the United States: ... 1238–1245, 2004. PMID: 15010446 National Center for Statistics and Analysis. 2014 Crash Data Key Findings (Traffic ...

75 FR 63519 - Notice of Availability of Draft Environmental Assessment and Draft Finding of No Significant...

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2010-10-15

... reduced for certain environmental resource areas (i.e., for transportation, public and occupational health... NUCLEAR REGULATORY COMMISSION [NRC-2009-0435] Notice of Availability of Draft Environmental... of Availability of Draft Environmental Assessment and Draft Finding of No Significant Impact; Notice...

76 FR 41528 - Notice of Availability of Environmental Assessment and Finding of No Significant Impact for...

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2011-07-14

... license renewal. Staff considered the following environmental resource areas in its evaluation: Land use... Protection and Performance Assessment Directorate, Division of Waste Management and Environmental Protection... Environmental Assessment and Finding of No Significant Impact for License Renewal for Uranium One USA Inc...

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.

Are studies reporting significant results more likely to be published?

Science.gov (United States)

Koletsi, Despina; Karagianni, Anthi; Pandis, Nikolaos; Makou, Margarita; Polychronopoulou, Argy; Eliades, Theodore

2009-11-01

Our objective was to assess the hypothesis that there are variations of the proportion of articles reporting a significant effect, with a higher percentage of those articles published in journals with impact factors. The contents of 5 orthodontic journals (American Journal of Orthodontics and Dentofacial Orthopedics, Angle Orthodontist, European Journal of Orthodontics, Journal of Orthodontics, and Orthodontics and Craniofacial Research), published between 2004 and 2008, were hand-searched. Articles with statistical analysis of data were included in the study and classified into 4 categories: behavior and psychology, biomaterials and biomechanics, diagnostic procedures and treatment, and craniofacial growth, morphology, and genetics. In total, 2622 articles were examined, with 1785 included in the analysis. Univariate and multivariate logistic regression analyses were applied with statistical significance as the dependent variable, and whether the journal had an impact factor, the subject, and the year were the independent predictors. A higher percentage of articles showed significant results relative to those without significant associations (on average, 88% vs 12%) for those journals. Overall, these journals published significantly more studies with significant results, ranging from 75% to 90% (P = 0.02). Multivariate modeling showed that journals with impact factors had a 100% increased probability of publishing a statistically significant result compared with journals with no impact factor (odds ratio [OR], 1.99; 95% CI, 1.19-3.31). Compared with articles on biomaterials and biomechanics, all other subject categories showed lower probabilities of significant results. Nonsignificant findings in behavior and psychology and diagnosis and treatment were 1.8 (OR, 1.75; 95% CI, 1.51-2.67) and 3.5 (OR, 3.50; 95% CI, 2.27-5.37) times more likely to be published, respectively. Journals seem to prefer reporting significant results; this might be because of authors

76 FR 56820 - Detroit Edison Company, Fermi 2; Environmental Assessment and Finding of No Significant Impact

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2011-09-14

.... Ken Yale, of the Michigan Department of Natural Resources and Environment regarding the environmental...; Environmental Assessment and Finding of No Significant Impact The U.S. Nuclear Regulatory Commission (NRC) is..., the NRC performed an environmental assessment. Based on the results of the environmental assessment...

78 FR 17383 - Notice of Availability of Environmental Assessment and Draft Finding of No Significant Impact...

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2013-03-21

... (truck, rail, and marine). DLA Energy's implementation of a systemic change to the use of commercial..., Terrestrial, and Cultural Resources--Transport and storage of fuel products is highly regulated. DLA Energy's... of Environmental Assessment and Draft Finding of No Significant Impact Regarding DLA Energy's...

Environmental Assessment and Finding of No Significant Impact: Pond B Dam Repair Project at the Savannah River Site

Energy Technology Data Exchange (ETDEWEB)

N/A

1999-09-27

The Department of Energy (DOE) has prepared an environmental assessment (EA) (DOE/EA-1285) for the proposed repair of the Pond B dam at the Savannah River Site (SRS), located near Aiken, South Carolina. Based on the analyses in the EA, DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act of 1969 (NEPA). Therefore, the preparation of an environmental impact statement (EIS) is not required, and DOE is issuing this Finding of No Significant Impact (FONSI) and Floodplain Statement of Findings.

75 FR 63518 - Notice of Availability of Environmental Assessment and Finding of No Significant Impact for...

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2010-10-15

...: I. Introduction The Nuclear Regulatory Commission (NRC) is considering the issuance of a license.... II. Finding of No Significant Impact Based on the analysis contained in this EA, the staff concluded... access the NRC's Agencywide Document Access and Management System (ADAMS), which provides text and image...

76 FR 19794 - Notice of Availability of Environmental Assessment and Finding of No Significant Impact for...

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2011-04-08

... . From this site, you can access the NRC's Agency Wide Document Access and Management System (ADAMS... Environmental Assessment and Finding of No Significant Impact for License Amendment for the University of Alaska... the release of an incinerator previously used at the Arctic Health Research Building for unrestricted...

Bayesian statistical inference

Directory of Open Access Journals (Sweden)

Bruno De Finetti

2017-04-01

Full Text Available This work was translated into English and published in the volume: Bruno De Finetti, Induction and Probability, Biblioteca di Statistica, eds. P. Monari, D. Cocchi, Clueb, Bologna, 1993.Bayesian statistical Inference is one of the last fundamental philosophical papers in which we can find the essential De Finetti's approach to the statistical inference.

75 FR 11575 - James A. Fitzpatrick Nuclear Power Plant Environmental Assessment and Finding of No Significant...

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2010-03-11

... Power Plant Environmental Assessment and Finding of No Significant Impact The U.S. Nuclear Regulatory...), for the operation of the James A. FitzPatrick Nuclear Power Plant (JAFNPP) located in Oswego County... the Final Environmental Statement for the James A. FitzPatrick Nuclear Power Plant, Docket No. 50-333...

Sunspot activity and influenza pandemics: a statistical assessment of the purported association.

Science.gov (United States)

Towers, S

2017-10-01

Since 1978, a series of papers in the literature have claimed to find a significant association between sunspot activity and the timing of influenza pandemics. This paper examines these analyses, and attempts to recreate the three most recent statistical analyses by Ertel (1994), Tapping et al. (2001), and Yeung (2006), which all have purported to find a significant relationship between sunspot numbers and pandemic influenza. As will be discussed, each analysis had errors in the data. In addition, in each analysis arbitrary selections or assumptions were also made, and the authors did not assess the robustness of their analyses to changes in those arbitrary assumptions. Varying the arbitrary assumptions to other, equally valid, assumptions negates the claims of significance. Indeed, an arbitrary selection made in one of the analyses appears to have resulted in almost maximal apparent significance; changing it only slightly yields a null result. This analysis applies statistically rigorous methodology to examine the purported sunspot/pandemic link, using more statistically powerful un-binned analysis methods, rather than relying on arbitrarily binned data. The analyses are repeated using both the Wolf and Group sunspot numbers. In all cases, no statistically significant evidence of any association was found. However, while the focus in this particular analysis was on the purported relationship of influenza pandemics to sunspot activity, the faults found in the past analyses are common pitfalls; inattention to analysis reproducibility and robustness assessment are common problems in the sciences, that are unfortunately not noted often enough in review.

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

Directory of Open Access Journals (Sweden)

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 interval or p-value--similarities and differences between two important methods of statistical inference of quantitative studies].

Science.gov (United States)

Harari, Gil

2014-01-01

Statistic significance, also known as p-value, and CI (Confidence Interval) are common statistics measures and are essential for the statistical analysis of studies in medicine and life sciences. These measures provide complementary information about the statistical probability and conclusions regarding the clinical significance of study findings. This article is intended to describe the methodologies, compare between the methods, assert their suitability for the different needs of study results analysis and to explain situations in which each method should be used.

Reversible Statistics

DEFF Research Database (Denmark)

Tryggestad, Kjell

2004-01-01

The study aims is to describe how the inclusion and exclusion of materials and calculative devices construct the boundaries and distinctions between statistical facts and artifacts in economics. My methodological approach is inspired by John Graunt's (1667) Political arithmetic and more recent work...... within constructivism and the field of Science and Technology Studies (STS). The result of this approach is here termed reversible statistics, reconstructing the findings of a statistical study within economics in three different ways. It is argued that all three accounts are quite normal, albeit...... in different ways. The presence and absence of diverse materials, both natural and political, is what distinguishes them from each other. Arguments are presented for a more symmetric relation between the scientific statistical text and the reader. I will argue that a more symmetric relation can be achieved...

Fibroadenomas of the breast showing an ill-defined margin on ultrasonogram: Correlation with histopathologic findings

International Nuclear Information System (INIS)

Hwang, Ji Young; Choi, Hye Young; Shim, Sung Shine; Rhee, Chung Sik; Sung, Soon Hee

2002-01-01

To correlate the sonographic finding of ill-defined fibroadenoma with the histopathologic findings. Sonographic finding of forty nine surgically proven fibroadenomas were retrospectively correlated with histopathologic findings. We evaluated sonographic findings including the margin, shape, size and the echotexture of fibroadenoma. The histopathologic glandular structure, stromal type of fibroadenoma, type of the surrounding breast tissue and presence of interdigitation between fibroadenoma and the surrounding breast tissue were pathologically reviewed and analyzed statistically. Breast sonography of fibroadenomas demonstrated well-defined margin in 28 (57%) and ill-defined margin in 21 (43%) among 49 lesions. Histopathologically, the glandular structure and type of the surrounding breast tissue were not significantly different between well-defined and ill-defined fibroadenomas. The stromal type of fibroadenoma was sclerotic in 8 (29%) well-defined fibroadenomas while sclerotic in 15 (72%) of 21 ill-defined fibroadenomas,showing difference with a statistical significance between well-defined and ill-defined fibroadenomas (p<0.05). Twenty (71%) of 28 fibroadenomas with well-defined sonographic margins showed well-defined border between mass and the surrounding breast tissue, pathologically. Meanwhile, twenty (95%) of 21 fibroadenomas with ill-defined sonographic margins demonstrated interdigitation of the surrounding breast tissue and mass, exhibiting a statistical significance (p<0.005). Ill-defined margins of fibroadenomas on sonography represent the interdigitation of the surrounding breast tissue with a mass and is seen in the sclerotic stromal type of fibroadenomas.

Fibroadenomas of the breast showing an ill-defined margin on ultrasonogram: Correlation with histopathologic findings

Energy Technology Data Exchange (ETDEWEB)

Hwang, Ji Young; Choi, Hye Young; Shim, Sung Shine; Rhee, Chung Sik; Sung, Soon Hee [Ewha Womans University College of Medicine, Seoul (Korea, Republic of)

2002-12-15

To correlate the sonographic finding of ill-defined fibroadenoma with the histopathologic findings. Sonographic finding of forty nine surgically proven fibroadenomas were retrospectively correlated with histopathologic findings. We evaluated sonographic findings including the margin, shape, size and the echotexture of fibroadenoma. The histopathologic glandular structure, stromal type of fibroadenoma, type of the surrounding breast tissue and presence of interdigitation between fibroadenoma and the surrounding breast tissue were pathologically reviewed and analyzed statistically. Breast sonography of fibroadenomas demonstrated well-defined margin in 28 (57%) and ill-defined margin in 21 (43%) among 49 lesions. Histopathologically, the glandular structure and type of the surrounding breast tissue were not significantly different between well-defined and ill-defined fibroadenomas. The stromal type of fibroadenoma was sclerotic in 8 (29%) well-defined fibroadenomas while sclerotic in 15 (72%) of 21 ill-defined fibroadenomas,showing difference with a statistical significance between well-defined and ill-defined fibroadenomas (p<0.05). Twenty (71%) of 28 fibroadenomas with well-defined sonographic margins showed well-defined border between mass and the surrounding breast tissue, pathologically. Meanwhile, twenty (95%) of 21 fibroadenomas with ill-defined sonographic margins demonstrated interdigitation of the surrounding breast tissue and mass, exhibiting a statistical significance (p<0.005). Ill-defined margins of fibroadenomas on sonography represent the interdigitation of the surrounding breast tissue with a mass and is seen in the sclerotic stromal type of fibroadenomas.

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.

East African Journal of Statistics

African Journals Online (AJOL)

AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING ... EASJOSTA publishes the latest findings in applied and theoretical statistics. ... mathematics and acturial sciences, all considered as part of applied statistics.

Statistics Anxiety and Worry: The Roles of Worry Beliefs, Negative Problem Orientation, and Cognitive Avoidance

Science.gov (United States)

Williams, Amanda S.

2015-01-01

Statistics anxiety is a common problem for graduate students. This study explores the multivariate relationship between a set of worry-related variables and six types of statistics anxiety. Canonical correlation analysis indicates a significant relationship between the two sets of variables. Findings suggest that students who are more intolerant…

Physics of Hard Spheres Experiment: Significant and Quantitative Findings Made

Science.gov (United States)

Doherty, Michael P.

2000-01-01

Direct examination of atomic interactions is difficult. One powerful approach to visualizing atomic interactions is to study near-index-matched colloidal dispersions of microscopic plastic spheres, which can be probed by visible light. Such spheres interact through hydrodynamic and Brownian forces, but they feel no direct force before an infinite repulsion at contact. Through the microgravity flight of the Physics of Hard Spheres Experiment (PHaSE), researchers have sought a more complete understanding of the entropically driven disorder-order transition in hard-sphere colloidal dispersions. The experiment was conceived by Professors Paul M. Chaikin and William B. Russel of Princeton University. Microgravity was required because, on Earth, index-matched colloidal dispersions often cannot be density matched, resulting in significant settling over the crystallization period. This settling makes them a poor model of the equilibrium atomic system, where the effect of gravity is truly negligible. For this purpose, a customized light-scattering instrument was designed, built, and flown by the NASA Glenn Research Center at Lewis Field on the space shuttle (shuttle missions STS 83 and STS 94). This instrument performed both static and dynamic light scattering, with sample oscillation for determining rheological properties. Scattered light from a 532- nm laser was recorded either by a 10-bit charge-coupled discharge (CCD) camera from a concentric screen covering angles of 0 to 60 or by sensitive avalanche photodiode detectors, which convert the photons into binary data from which two correlators compute autocorrelation functions. The sample cell was driven by a direct-current servomotor to allow sinusoidal oscillation for the measurement of rheological properties. Significant microgravity research findings include the observation of beautiful dendritic crystals, the crystallization of a "glassy phase" sample in microgravity that did not crystallize for over 1 year in 1g

Electrophysiologic Findings and Pain in Carpal Tunnel Syndrome

Directory of Open Access Journals (Sweden)

Hava Dönmez Keklikoğlu

2009-12-01

Full Text Available OBJECTIVE: Carpal tunnel syndrome (CTS is defined as median nerve entrapment within the carpal tunnel at the wrist. Pain and paresthesia are the most common presenting symptoms of the patients. In this study, our aim was to identify the association between intensity of presenting symptoms and electrophysiologic findings in patients referred to the electrophysiology laboratory with prediagnosis of CTS. METHODS: Sixty-two consecutive patients who were referred to the electrophysiology laboratory with the diagnosis of CTS were enrolled in the study. The intensity of pain was determined by visual analog scale, the findings of Tinel-Phalen tests were assessed, and clinico-demographic findings were recorded. Nerve conduction studies were performed bilaterally in median and ulnar nerves. The severity of CTS was determined with electrophysiologic evaluation, and the association between electrophysiologic findings and symptoms were analyzed statistically. RESULTS: Sixty-two (57 female, 5 male patients were examined in the study. CTS was bilateral in 53 patients and unilateral in 9 patients (total 115 hands. Mean pain score was 5.78 ± 3.50. In 28 hands with a clinical diagnosis of CTS, no electrophysiologic CTS findings were found, whereas in 32 hands mild, in 41 hands moderate and in 14 hands severe findings were obtained. CONCLUSION: According to our study, there was no statistically significant association between severity of symptoms and severity of electrophysiologic findings in CTS

Aspects of statistical consulting not taught by acedemia

DEFF Research Database (Denmark)

Kenett, R.; Thyregod, Poul

2006-01-01

Education in statistics is preparing for statistical analysis but not necessarily for statistical consulting. The objective of this paper is to explore the phases that precede and follow statistical analysis. Specifically these include: problem elicitation, data collection and, following statisti......Education in statistics is preparing for statistical analysis but not necessarily for statistical consulting. The objective of this paper is to explore the phases that precede and follow statistical analysis. Specifically these include: problem elicitation, data collection and, following...... statistical data analysis, formulation of findings, and presentation of findings, and recommendations. Some insights derived from a literature review and real-life case studies are provided. Areas for joint research by statisticians and cognitive scientists are outlined....

Image Statistics

Energy Technology Data Exchange (ETDEWEB)

Wendelberger, Laura Jean [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-08-08

In large datasets, it is time consuming or even impossible to pick out interesting images. Our proposed solution is to find statistics to quantify the information in each image and use those to identify and pick out images of interest.

Clinical, hematological, and biochemical findings in puppies with coronavirus and parvovirus enteritis

Science.gov (United States)

Castro, Tatiana X.; Cubel Garcia, Rita de Cássia N.; Gonçalves, Luciana P. S.; Costa, Erika M.; Marcello, Gracy C.G.; Labarthe, Norma V.; Mendes-de-Almeida, Flavya

2013-01-01

The clinical and laboratory findings in puppies naturally infected with canine coronavirus (CCoV) and/or canine parvovirus (CPV) were compared with findings in uninfected puppies. Lymphopenia was the only parameter related to CCoV infection that was statistically significant; vomiting, anorexia, lethargy, hemorrhagic fluid diarrhea, leukopenia, lymphopenia, thrombocytopenia, hypoglycemia, and hypoproteinemia were correlated with CPV infection. PMID:24155496

Accessory ossicles and sesamoid bones of the ankle and foot: imaging findings, clinical significance and differential diagnosis

International Nuclear Information System (INIS)

Mellado, J.M.; Ramos, A.; Salvado, E.; Camins, A.; Sauri, A.; Danus, M.

2003-01-01

Accessory ossicles and sesamoid bones are frequent findings in routine radiographs of the ankle and foot. They are commonly considered fortuitous and unrelated to the patient's complaint; however, they may eventually cause painful syndromes or degenerative changes in response to overuse and trauma. They may also suffer or simulate fractures. Our aim was to review, illustrate and discuss the imaging findings of some of the more frequent accessory ossicles and sesamoid bones of the ankle and foot region, with particular emphasis on those that may be of clinical significance or simulate fractures. (orig.)

Evaluating statistical tests on OLAP cubes to compare degree of disease.

Science.gov (United States)

Ordonez, Carlos; Chen, Zhibo

2009-09-01

Statistical tests represent an important technique used to formulate and validate hypotheses on a dataset. They are particularly useful in the medical domain, where hypotheses link disease with medical measurements, risk factors, and treatment. In this paper, we propose to compute parametric statistical tests treating patient records as elements in a multidimensional cube. We introduce a technique that combines dimension lattice traversal and statistical tests to discover significant differences in the degree of disease within pairs of patient groups. In order to understand a cause-effect relationship, we focus on patient group pairs differing in one dimension. We introduce several optimizations to prune the search space, to discover significant group pairs, and to summarize results. We present experiments showing important medical findings and evaluating scalability with medical datasets.

Mid-Columbia Coho Reintroduction Feasibility Project : Final Environmental Assessment and Finding of No Significant Impact.

Energy Technology Data Exchange (ETDEWEB)

United States. Bonneville Power Administration; Confederated Tribes and Bands of the Yakama Nation; Washington State Department of Fish and Wildlife

1999-04-01

Bonneville Power Administration (BPA) is proposing to fund research for 2 to 3 years on the feasibility of reintroducing coho salmon into mid-Columbia River basin tributaries. The research would take place in the Methow and Wenatchee river basins in Chelan and Okanogan Counties, Washington. BPA has prepared an Environmental Assessment (EA) (DOE/EA-1282) evaluating the proposed project. Based on the analysis in the EA, BPA has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement (EIS) is not required, and BPA is issuing this Finding of No Significant Impact.

Mid-Columbia Coho Reintroduction Feasibility Project. Final Environmental Assessment and Finding of No Significant Impact

International Nuclear Information System (INIS)

1999-01-01

Bonneville Power Administration (BPA) is proposing to fund research for 2 to 3 years on the feasibility of reintroducing coho salmon into mid-Columbia River basin tributaries. The research would take place in the Methow and Wenatchee river basins in Chelan and Okanogan Counties, Washington. BPA has prepared an Environmental Assessment (EA) (DOE/EA-1282) evaluating the proposed project. Based on the analysis in the EA, BPA has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement (EIS) is not required, and BPA is issuing this Finding of No Significant Impact

Statistical learning across development: Flexible yet constrained

Directory of Open Access Journals (Sweden)

Lauren eKrogh

2013-01-01

Full Text Available Much research in the past two decades has documented infants’ and adults' ability to extract statistical regularities from auditory input. Importantly, recent research has extended these findings to the visual domain, demonstrating learners' sensitivity to statistical patterns within visual arrays and sequences of shapes. In this review we discuss both auditory and visual statistical learning to elucidate both the generality of and constraints on statistical learning. The review first outlines the major findings of the statistical learning literature with infants, followed by discussion of statistical learning across domains, modalities, and development. The second part of this review considers constraints on statistical learning. The discussion focuses on two categories of constraint: constraints on the types of input over which statistical learning operates and constraints based on the state of the learner. The review concludes with a discussion of possible mechanisms underlying statistical learning.

Correlation of MRI findings with clinical findings of trochanteric pain syndrome

Energy Technology Data Exchange (ETDEWEB)

Blankenbaker, Donna G.; Ullrick, Steven R.; Davis, Kirkland W.; De Smet, Arthur A. [University of Wisconsin School of Medicine and Public Health, Department of Radiology, Madison, WI (United States); Haaland, Ben; Fine, Jason P. [University of Wisconsin School of Medicine and Public Health, Departments of Biostatistics and Medical Informatics and Statistics, Madison, WI (United States)

2008-10-15

Greater trochanter pain syndrome due to tendinopathy or bursitis is a common cause of hip pain. The previously reported magnetic resonance (MR) findings of trochanteric tendinopathy and bursitis are peritrochanteric fluid and abductor tendon abnormality. We have often noted peritrochanteric high T2 signal in patients without trochanteric symptoms. The purpose of this study was to determine whether the MR findings of peritrochanteric fluid or hip abductor tendon pathology correlate with trochanteric pain. We retrospectively reviewed 131 consecutive MR examinations of the pelvis (256 hips) for T2 peritrochanteric signal and abductor tendon abnormalities without knowledge of the clinical symptoms. Any T2 peritrochanteric abnormality was characterized by size as tiny, small, medium, or large; by morphology as feathery, crescentic, or round; and by location as bursal or intratendinous. The clinical symptoms of hip pain and trochanteric pain were compared to the MR findings on coronal, sagittal, and axial T2 sequences using chi-square or Fisher's exact test with significance assigned as p<0.05. Clinical symptoms of trochanteric pain syndrome were present in only 16 of the 256 hips. All 16 hips with trochanteric pain and 212 (88%) of 240 without trochanteric pain had peritrochanteric abnormalities (p=0.15). Eighty-eight percent of hips with trochanteric symptoms had gluteus tendinopathy while 50% of those without symptoms had such findings (p=0.004). Other than tendinopathy, there was no statistically significant difference between hips with or without trochanteric symptoms and the presence of peritrochanteric T2 abnormality, its size or shape, and the presence of gluteus medius or minimus partial thickness tears. Patients with trochanteric pain syndrome always have peritrochanteric T2 abnormalities and are significantly more likely to have abductor tendinopathy on magnetic resonance imaging (MRI). However, although the absence of peritrochanteric T2 MR abnormalities

Correlation of MRI findings with clinical findings of trochanteric pain syndrome

International Nuclear Information System (INIS)

Blankenbaker, Donna G.; Ullrick, Steven R.; Davis, Kirkland W.; De Smet, Arthur A.; Haaland, Ben; Fine, Jason P.

2008-01-01

Greater trochanter pain syndrome due to tendinopathy or bursitis is a common cause of hip pain. The previously reported magnetic resonance (MR) findings of trochanteric tendinopathy and bursitis are peritrochanteric fluid and abductor tendon abnormality. We have often noted peritrochanteric high T2 signal in patients without trochanteric symptoms. The purpose of this study was to determine whether the MR findings of peritrochanteric fluid or hip abductor tendon pathology correlate with trochanteric pain. We retrospectively reviewed 131 consecutive MR examinations of the pelvis (256 hips) for T2 peritrochanteric signal and abductor tendon abnormalities without knowledge of the clinical symptoms. Any T2 peritrochanteric abnormality was characterized by size as tiny, small, medium, or large; by morphology as feathery, crescentic, or round; and by location as bursal or intratendinous. The clinical symptoms of hip pain and trochanteric pain were compared to the MR findings on coronal, sagittal, and axial T2 sequences using chi-square or Fisher's exact test with significance assigned as p<0.05. Clinical symptoms of trochanteric pain syndrome were present in only 16 of the 256 hips. All 16 hips with trochanteric pain and 212 (88%) of 240 without trochanteric pain had peritrochanteric abnormalities (p=0.15). Eighty-eight percent of hips with trochanteric symptoms had gluteus tendinopathy while 50% of those without symptoms had such findings (p=0.004). Other than tendinopathy, there was no statistically significant difference between hips with or without trochanteric symptoms and the presence of peritrochanteric T2 abnormality, its size or shape, and the presence of gluteus medius or minimus partial thickness tears. Patients with trochanteric pain syndrome always have peritrochanteric T2 abnormalities and are significantly more likely to have abductor tendinopathy on magnetic resonance imaging (MRI). However, although the absence of peritrochanteric T2 MR abnormalities

Evaluation of early atherosclerotic findings in women with polycystic ovary syndrome

Directory of Open Access Journals (Sweden)

Mohammadi Afshin

2011-10-01

Full Text Available Background Polycystic ovary syndrome (PCOS is the most common endocrinopathy in women of childbearing age, and it seems better to consider it as an ovarian manifestation of metabolic syndrome. The aim of the current study was to evaluate early atherosclerotic findings in patients with PCOS. Methods We enrolled 46 women with PCOS and 45 normal control subjects who were referred to our hospital's endocrinology outpatient clinic. Carotid intima media thickness (CIMT and flow-mediated dilatation (FMD were performed in both cases and matched controls. Results Patients with PCOS showed an increased mean CIMT (0.63 ± 0.16 mm when compared with the control subjects (0.33 ± 0.06 mm. This difference was statistically significant (p = 0.001. The mean FMD in young patients with PCOS was 10.07 ± 1.2%, while it was 6.5 ± 2.06% in normal subjects. This difference was also statistically significant (p = 0.001. Conclusion Our findings suggest that PCOS is related with early atherosclerotic findings.

Debate on GMOs health risks after statistical findings in regulatory tests.

Science.gov (United States)

de Vendômois, Joël Spiroux; Cellier, Dominique; Vélot, Christian; Clair, Emilie; Mesnage, Robin; Séralini, Gilles-Eric

2010-10-05

We summarize the major points of international debate on health risk studies for the main commercialized edible GMOs. These GMOs are soy, maize and oilseed rape designed to contain new pesticide residues since they have been modified to be herbicide-tolerant (mostly to Roundup) or to produce mutated Bt toxins. The debated alimentary chronic risks may come from unpredictable insertional mutagenesis effects, metabolic effects, or from the new pesticide residues. The most detailed regulatory tests on the GMOs are three-month long feeding trials of laboratory rats, which are biochemically assessed. The tests are not compulsory, and are not independently conducted. The test data and the corresponding results are kept in secret by the companies. Our previous analyses of regulatory raw data at these levels, taking the representative examples of three GM maize NK 603, MON 810, and MON 863 led us to conclude that hepatorenal toxicities were possible, and that longer testing was necessary. Our study was criticized by the company developing the GMOs in question and the regulatory bodies, mainly on the divergent biological interpretations of statistically significant biochemical and physiological effects. We present the scientific reasons for the crucially different biological interpretations and also highlight the shortcomings in the experimental protocols designed by the company. The debate implies an enormous responsibility towards public health and is essential due to nonexistent traceability or epidemiological studies in the GMO-producing countries.

Narrative Review of Statistical Reporting Checklists, Mandatory Statistical Editing, and Rectifying Common Problems in the Reporting of Scientific Articles.

Science.gov (United States)

Dexter, Franklin; Shafer, Steven L

2017-03-01

Considerable attention has been drawn to poor reproducibility in the biomedical literature. One explanation is inadequate reporting of statistical methods by authors and inadequate assessment of statistical reporting and methods during peer review. In this narrative review, we examine scientific studies of several well-publicized efforts to improve statistical reporting. We also review several retrospective assessments of the impact of these efforts. These studies show that instructions to authors and statistical checklists are not sufficient; no findings suggested that either improves the quality of statistical methods and reporting. Second, even basic statistics, such as power analyses, are frequently missing or incorrectly performed. Third, statistical review is needed for all papers that involve data analysis. A consistent finding in the studies was that nonstatistical reviewers (eg, "scientific reviewers") and journal editors generally poorly assess statistical quality. We finish by discussing our experience with statistical review at Anesthesia & Analgesia from 2006 to 2016.

76 FR 8708 - Availability of an Environmental Assessment and Finding of No Significant Impact for a Biological...

Science.gov (United States)

2011-02-15

...] Availability of an Environmental Assessment and Finding of No Significant Impact for a Biological Control Agent... have been prepared by the Animal and Plant Health Inspection Service relative to a proposed biological... review and analysis of environmental impacts associated with the proposed biological control program...

CORRELATIONS BETWEEN FINDINGS OF OCCLUSAL AND MANUAL ANALYSIS IN TMD-PATIENTS

Directory of Open Access Journals (Sweden)

Mariana Dimova

2016-08-01

Full Text Available The aim of this study was to investigate and analyze the possible correlations between findings by manual functional analysis and clinical occlusal analysis in TMD-patients. Material and methods: Material of this study are 111 TMD-patients selected after visual diagnostics, functional brief review under Ahlers Jakstatt, intraoral examination and taking periodontal status. In the period September 2014 - March 2016 all patients were subjected to manual functional analysis and clinical occlusal analysis. 17 people (10 women and 7 men underwent imaging with cone-beam computed tomography. Results: There were found many statistically significant correlations between tests of the structural analysis that indicate the relationships between findings. Conclusion: The presence of statistically significant correlations between occlusal relationships, freedom in the centric and condition of the muscle complex of masticatory system and TMJ confirm the relationship between the state of occlusal components and TMD.

Multiparametric statistics

CERN Document Server

Serdobolskii, Vadim Ivanovich

2007-01-01

This monograph presents mathematical theory of statistical models described by the essentially large number of unknown parameters, comparable with sample size but can also be much larger. In this meaning, the proposed theory can be called "essentially multiparametric". It is developed on the basis of the Kolmogorov asymptotic approach in which sample size increases along with the number of unknown parameters.This theory opens a way for solution of central problems of multivariate statistics, which up until now have not been solved. Traditional statistical methods based on the idea of an infinite sampling often break down in the solution of real problems, and, dependent on data, can be inefficient, unstable and even not applicable. In this situation, practical statisticians are forced to use various heuristic methods in the hope the will find a satisfactory solution.Mathematical theory developed in this book presents a regular technique for implementing new, more efficient versions of statistical procedures. ...

The anterior tilt angle of the proximal tibia epiphyseal plate: A significant radiological finding in young children with trampoline fractures

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Stranzinger, Enno, E-mail: enno.stranzinger@insel.ch [University Hospital Bern, Inselspital, Department of Diagnostic, Interventional and Pediatric Radiology, CH-3010 Bern (Switzerland); Leidolt, Lars, E-mail: lars.leidolt@insel.ch [University Hospital Bern, Inselspital, Department of Diagnostic, Interventional and Pediatric Radiology, CH-3010 Bern (Switzerland); Eich, Georg, E-mail: georg.eich@ksa.ch [Cantonal Hospital Aarau, Pediatric Radiology, Tellstrasse, CH-5001 Aarau (Switzerland); Klimek, Peter Michael, E-mail: peter.klimek@ksa.ch [Cantonal Hospital Aarau, Pediatric Surgery, Tellstrasse, CH-5001 Aarau (Switzerland)

2014-08-15

Objective: Evaluation of the anterior tilt angle of the proximal tibia epiphyseal plate in young children, which suffered a trampoline fracture in comparison with a normal population. Materials and methods: 62 children (31 females, 31 males) between 2 and 5 years of age (average 2 years 11 months, standard deviation 11 months) with radiographs in two views of the tibia were included in this retrospective study. 25 children with proximal tibia fractures were injured with a history of jumping on a trampoline. All other causes for tibia fractures were excluded. A normal age-mapped control cohort of 37 children was compared. These children had neither evidence of a trampoline related injury nor a fracture of the tibia. The anterior tilt angle of the epiphyseal plate of the tibia was defined as an angle between the proximal tibia physis and the distal tibia physis on a lateral view. Two radiologists evaluated all radiographs for fractures and measured the anterior tilt angle in consensus. An unpaired Student's t-test was used for statistical analysis (SPSS). Original reports were reviewed and compared with the radiological findings and follow-up radiographs. Results: In the normal control group, the average anterior tilt angle measured −3.2°, SD ± 2.8°. The children with trampoline fractures showed an anterior tilt of +4.4°, SD ± 2.9°. The difference was statistically significant, P < 0.0001. In 6 patients (24% of all patients with confirmed fractures) the original report missed to diagnose the proximal tibial fracture. Conclusion: Young children between 2 and 5 years of age are at risk for proximal tibia fractures while jumping on a trampoline. These fractures may be very subtle and difficult to detect on initial radiographs. Measurement of the anterior tilt angle of the proximal tibia epiphyseal plate on lateral radiographs is supportive for interpreting correctly trampoline fractures.

The anterior tilt angle of the proximal tibia epiphyseal plate: A significant radiological finding in young children with trampoline fractures

International Nuclear Information System (INIS)

Stranzinger, Enno; Leidolt, Lars; Eich, Georg; Klimek, Peter Michael

2014-01-01

Objective: Evaluation of the anterior tilt angle of the proximal tibia epiphyseal plate in young children, which suffered a trampoline fracture in comparison with a normal population. Materials and methods: 62 children (31 females, 31 males) between 2 and 5 years of age (average 2 years 11 months, standard deviation 11 months) with radiographs in two views of the tibia were included in this retrospective study. 25 children with proximal tibia fractures were injured with a history of jumping on a trampoline. All other causes for tibia fractures were excluded. A normal age-mapped control cohort of 37 children was compared. These children had neither evidence of a trampoline related injury nor a fracture of the tibia. The anterior tilt angle of the epiphyseal plate of the tibia was defined as an angle between the proximal tibia physis and the distal tibia physis on a lateral view. Two radiologists evaluated all radiographs for fractures and measured the anterior tilt angle in consensus. An unpaired Student's t-test was used for statistical analysis (SPSS). Original reports were reviewed and compared with the radiological findings and follow-up radiographs. Results: In the normal control group, the average anterior tilt angle measured −3.2°, SD ± 2.8°. The children with trampoline fractures showed an anterior tilt of +4.4°, SD ± 2.9°. The difference was statistically significant, P < 0.0001. In 6 patients (24% of all patients with confirmed fractures) the original report missed to diagnose the proximal tibial fracture. Conclusion: Young children between 2 and 5 years of age are at risk for proximal tibia fractures while jumping on a trampoline. These fractures may be very subtle and difficult to detect on initial radiographs. Measurement of the anterior tilt angle of the proximal tibia epiphyseal plate on lateral radiographs is supportive for interpreting correctly trampoline fractures

The earth is flat (p > 0.05): significance thresholds and the crisis of unreplicable research.

Science.gov (United States)

Amrhein, Valentin; Korner-Nievergelt, Fränzi; Roth, Tobias

2017-01-01

The widespread use of 'statistical significance' as a license for making a claim of a scientific finding leads to considerable distortion of the scientific process (according to the American Statistical Association). We review why degrading p -values into 'significant' and 'nonsignificant' contributes to making studies irreproducible, or to making them seem irreproducible. A major problem is that we tend to take small p -values at face value, but mistrust results with larger p -values. In either case, p -values tell little about reliability of research, because they are hardly replicable even if an alternative hypothesis is true. Also significance ( p  ≤ 0.05) is hardly replicable: at a good statistical power of 80%, two studies will be 'conflicting', meaning that one is significant and the other is not, in one third of the cases if there is a true effect. A replication can therefore not be interpreted as having failed only because it is nonsignificant. Many apparent replication failures may thus reflect faulty judgment based on significance thresholds rather than a crisis of unreplicable research. Reliable conclusions on replicability and practical importance of a finding can only be drawn using cumulative evidence from multiple independent studies. However, applying significance thresholds makes cumulative knowledge unreliable. One reason is that with anything but ideal statistical power, significant effect sizes will be biased upwards. Interpreting inflated significant results while ignoring nonsignificant results will thus lead to wrong conclusions. But current incentives to hunt for significance lead to selective reporting and to publication bias against nonsignificant findings. Data dredging, p -hacking, and publication bias should be addressed by removing fixed significance thresholds. Consistent with the recommendations of the late Ronald Fisher, p -values should be interpreted as graded measures of the strength of evidence against the null hypothesis

Topics in theoretical and applied statistics

CERN Document Server

Giommi, Andrea

2016-01-01

This book highlights the latest research findings from the 46th International Meeting of the Italian Statistical Society (SIS) in Rome, during which both methodological and applied statistical research was discussed. This selection of fully peer-reviewed papers, originally presented at the meeting, addresses a broad range of topics, including the theory of statistical inference; data mining and multivariate statistical analysis; survey methodologies; analysis of social, demographic and health data; and economic statistics and econometrics.

76 FR 71583 - Notice of Availability of Finding of No Significant Impact for Field Release of Insects for...

Science.gov (United States)

2011-11-18

... Finding of No Significant Impact for Field Release of Insects for Biological Control of Carrizo Cane... insects, the Arundo scale and the Arundo wasp as biological control agents for the non-native and invasive... [[Page 71584

Learning Predictive Statistics: Strategies and Brain Mechanisms.

Science.gov (United States)

Wang, Rui; Shen, Yuan; Tino, Peter; Welchman, Andrew E; Kourtzi, Zoe

2017-08-30

When immersed in a new environment, we are challenged to decipher initially incomprehensible streams of sensory information. However, quite rapidly, the brain finds structure and meaning in these incoming signals, helping us to predict and prepare ourselves for future actions. This skill relies on extracting the statistics of event streams in the environment that contain regularities of variable complexity from simple repetitive patterns to complex probabilistic combinations. Here, we test the brain mechanisms that mediate our ability to adapt to the environment's statistics and predict upcoming events. By combining behavioral training and multisession fMRI in human participants (male and female), we track the corticostriatal mechanisms that mediate learning of temporal sequences as they change in structure complexity. We show that learning of predictive structures relates to individual decision strategy; that is, selecting the most probable outcome in a given context (maximizing) versus matching the exact sequence statistics. These strategies engage distinct human brain regions: maximizing engages dorsolateral prefrontal, cingulate, sensory-motor regions, and basal ganglia (dorsal caudate, putamen), whereas matching engages occipitotemporal regions (including the hippocampus) and basal ganglia (ventral caudate). Our findings provide evidence for distinct corticostriatal mechanisms that facilitate our ability to extract behaviorally relevant statistics to make predictions. SIGNIFICANCE STATEMENT Making predictions about future events relies on interpreting streams of information that may initially appear incomprehensible. Past work has studied how humans identify repetitive patterns and associative pairings. However, the natural environment contains regularities that vary in complexity from simple repetition to complex probabilistic combinations. Here, we combine behavior and multisession fMRI to track the brain mechanisms that mediate our ability to adapt to

Prevalence of ocular findings in a sample of Egyptian patients with psoriasis

Directory of Open Access Journals (Sweden)

Salma Samir Omar

2018-01-01

Conclusion: This is the first report on the prevalence of eye comorbidities in Egyptian psoriatic patients. Dry eyes were more common with psoriasis, particularly the erythrodermic type. Other ocular findings were not statistically significantly different except for conjunctival injection and pinguecula.

Pedagogical Utilization and Assessment of the Statistic Online Computational Resource in Introductory Probability and Statistics Courses.

Science.gov (United States)

Dinov, Ivo D; Sanchez, Juana; Christou, Nicolas

2008-01-01

Technology-based instruction represents a new recent pedagogical paradigm that is rooted in the realization that new generations are much more comfortable with, and excited about, new technologies. The rapid technological advancement over the past decade has fueled an enormous demand for the integration of modern networking, informational and computational tools with classical pedagogical instruments. Consequently, teaching with technology typically involves utilizing a variety of IT and multimedia resources for online learning, course management, electronic course materials, and novel tools of communication, engagement, experimental, critical thinking and assessment.The NSF-funded Statistics Online Computational Resource (SOCR) provides a number of interactive tools for enhancing instruction in various undergraduate and graduate courses in probability and statistics. These resources include online instructional materials, statistical calculators, interactive graphical user interfaces, computational and simulation applets, tools for data analysis and visualization. The tools provided as part of SOCR include conceptual simulations and statistical computing interfaces, which are designed to bridge between the introductory and the more advanced computational and applied probability and statistics courses. In this manuscript, we describe our designs for utilizing SOCR technology in instruction in a recent study. In addition, present the results of the effectiveness of using SOCR tools at two different course intensity levels on three outcome measures: exam scores, student satisfaction and choice of technology to complete assignments. Learning styles assessment was completed at baseline. We have used three very different designs for three different undergraduate classes. Each course included a treatment group, using the SOCR resources, and a control group, using classical instruction techniques. Our findings include marginal effects of the SOCR treatment per individual

Intuitive introductory statistics

CERN Document Server

Wolfe, Douglas A

2017-01-01

This textbook is designed to give an engaging introduction to statistics and the art of data analysis. The unique scope includes, but also goes beyond, classical methodology associated with the normal distribution. What if the normal model is not valid for a particular data set? This cutting-edge approach provides the alternatives. It is an introduction to the world and possibilities of statistics that uses exercises, computer analyses, and simulations throughout the core lessons. These elementary statistical methods are intuitive. Counting and ranking features prominently in the text. Nonparametric methods, for instance, are often based on counts and ranks and are very easy to integrate into an introductory course. The ease of computation with advanced calculators and statistical software, both of which factor into this text, allows important techniques to be introduced earlier in the study of statistics. This book's novel scope also includes measuring symmetry with Walsh averages, finding a nonp...

Beginning R The Statistical Programming Language

CERN Document Server

Gardener, Mark

2012-01-01

Conquer the complexities of this open source statistical language R is fast becoming the de facto standard for statistical computing and analysis in science, business, engineering, and related fields. This book examines this complex language using simple statistical examples, showing how R operates in a user-friendly context. Both students and workers in fields that require extensive statistical analysis will find this book helpful as they learn to use R for simple summary statistics, hypothesis testing, creating graphs, regression, and much more. It covers formula notation, complex statistics

Low statistical power in biomedical science: a review of three human research domains

Science.gov (United States)

Dumas-Mallet, Estelle; Button, Katherine S.; Boraud, Thomas; Gonon, Francois

2017-01-01

Studies with low statistical power increase the likelihood that a statistically significant finding represents a false positive result. We conducted a review of meta-analyses of studies investigating the association of biological, environmental or cognitive parameters with neurological, psychiatric and somatic diseases, excluding treatment studies, in order to estimate the average statistical power across these domains. Taking the effect size indicated by a meta-analysis as the best estimate of the likely true effect size, and assuming a threshold for declaring statistical significance of 5%, we found that approximately 50% of studies have statistical power in the 0–10% or 11–20% range, well below the minimum of 80% that is often considered conventional. Studies with low statistical power appear to be common in the biomedical sciences, at least in the specific subject areas captured by our search strategy. However, we also observe evidence that this depends in part on research methodology, with candidate gene studies showing very low average power and studies using cognitive/behavioural measures showing high average power. This warrants further investigation. PMID:28386409

Statistical deception at work

CERN Document Server

Mauro, John

2013-01-01

Written to reveal statistical deceptions often thrust upon unsuspecting journalists, this book views the use of numbers from a public perspective. Illustrating how the statistical naivete of journalists often nourishes quantitative misinformation, the author's intent is to make journalists more critical appraisers of numerical data so that in reporting them they do not deceive the public. The book frequently uses actual reported examples of misused statistical data reported by mass media and describes how journalists can avoid being taken in by them. Because reports of survey findings seldom g

Finding of No Significant Impact and Environmental Assessment for Flight Test to the Edge of Space

Science.gov (United States)

2008-12-01

Runway 22 or on Rogers Dry Lakebed at Edwards AFB. 17 On the basis of the findings of the Environmental Assessment, no significant impact to human...FLIGHT TEST CENTER Environmental Assessment for Flight Test to the Edge of Space Page 5-3 Bowles, A.E., S. Eckert, L . Starke, E. Berg, L . Wolski, and...Numbers. Anne Choate, Laura 20 Pederson , Jeremy Scharfenberg, Henry Farland. Washington, D.C. September. 21 Jeppesen Sanderson, Incorporated 22

Diagnostic accuracy of the clinical and CT findings for differentiating Kikuchi's disease and tuberculous lymphadenitis presenting with cervical lymphadenopathy.

Science.gov (United States)

Baek, Hye Jin; Lee, Jeong Hyun; Lim, Hyun Kyung; Lee, Ha Young; Baek, Jung Hwan

2014-11-01

To determine the optimal clinical and CT findings for differentiating Kikuchi's disease (KD) and tuberculous lymphadenitis (TB) in patients presenting with cervical lymphadenopathy. From 2006 to 2010, 87 consecutive patients who were finally diagnosed with KD or TB were enrolled. Two radiologists performed independent analysis of contrast-enhanced neck CT images with regard to the involvement pattern, nodal or perinodal changes, and evidence of the previous infection. Significant clinical and CT findings of KD were determined by statistical analyses. Of the 87 patients, 27 (31%) were classified as having KD and 60 (69%) as having TB. Statistically significant findings of KD patients were younger age, presence of fever, involvement of ≥5 nodal levels or the bilateral neck, no or minimal nodal necrosis, marked perinodal infiltration, and no evidence of upper lung lesion or mediastinal lymphadenopathy. The presence of four or more statistically significant clinical and CT findings of KD had the largest area under the receiver-operating characteristic curve (A z = 0.861; 95% confidence intervals 0.801, 0.909), with a sensitivity of 89% and specificity of 83%. CT can be a helpful tool for differentiating KD from TB, especially when it is combined with the clinical findings.

Pattern statistics on Markov chains and sensitivity to parameter estimation

Directory of Open Access Journals (Sweden)

Nuel Grégory

2006-10-01

Full Text Available Abstract Background: In order to compute pattern statistics in computational biology a Markov model is commonly used to take into account the sequence composition. Usually its parameter must be estimated. The aim of this paper is to determine how sensitive these statistics are to parameter estimation, and what are the consequences of this variability on pattern studies (finding the most over-represented words in a genome, the most significant common words to a set of sequences,.... Results: In the particular case where pattern statistics (overlap counting only computed through binomial approximations we use the delta-method to give an explicit expression of σ, the standard deviation of a pattern statistic. This result is validated using simulations and a simple pattern study is also considered. Conclusion: We establish that the use of high order Markov model could easily lead to major mistakes due to the high sensitivity of pattern statistics to parameter estimation.

42 CFR 417.568 - Adequate financial records, statistical data, and cost finding.

Science.gov (United States)

2010-10-01

... this section, on the accrual method of accounting. (3) For governmental institutions that use a cash basis of accounting, cost data developed on this basis is acceptable. However, only depreciation on... definitions and accounting, statistics, and reporting practices that are widely accepted in the health care...

Environmental Assessment and Finding of No Significant Impact: Implementation of the Wetland Mitigation Bank Program at the Savannah River Site

Energy Technology Data Exchange (ETDEWEB)

N/A

1999-04-28

The Department of Energy (DOE) has prepared an environmental assessment (EA) (DOE/EA-1205) for the proposed implementation of a wetland mitigation bank program at the Savannah River Site (SRS), located near Aiken, South Carolina. Based on the analyses in the EA, DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act of 1969 (NEPA). Therefore, the preparation of an environmental impact statement (EIS) is not required, and DOE is issuing this Finding of No Significant Impact (FONSI) and Floodplain Statement of Findings.

Quality of statistical reporting in developmental disability journals.

Science.gov (United States)

Namasivayam, Aravind K; Yan, Tina; Wong, Wing Yiu Stephanie; van Lieshout, Pascal

2015-12-01

Null hypothesis significance testing (NHST) dominates quantitative data analysis, but its use is controversial and has been heavily criticized. The American Psychological Association has advocated the reporting of effect sizes (ES), confidence intervals (CIs), and statistical power analysis to complement NHST results to provide a more comprehensive understanding of research findings. The aim of this paper is to carry out a sample survey of statistical reporting practices in two journals with the highest h5-index scores in the areas of developmental disability and rehabilitation. Using a checklist that includes critical recommendations by American Psychological Association, we examined 100 randomly selected articles out of 456 articles reporting inferential statistics in the year 2013 in the Journal of Autism and Developmental Disorders (JADD) and Research in Developmental Disabilities (RDD). The results showed that for both journals, ES were reported only half the time (JADD 59.3%; RDD 55.87%). These findings are similar to psychology journals, but are in stark contrast to ES reporting in educational journals (73%). Furthermore, a priori power and sample size determination (JADD 10%; RDD 6%), along with reporting and interpreting precision measures (CI: JADD 13.33%; RDD 16.67%), were the least reported metrics in these journals, but not dissimilar to journals in other disciplines. To advance the science in developmental disability and rehabilitation and to bridge the research-to-practice divide, reforms in statistical reporting, such as providing supplemental measures to NHST, are clearly needed.

Tucannon River Spring Chinook Captive Broodstock Program Final Environmental Assessment and Finding of No Significant Impact

Energy Technology Data Exchange (ETDEWEB)

N/A

2000-05-24

Bonneville Power Administration (BPA) is proposing to fund the Tucannon River Spring Chinook Captive Broodstock Program, a small-scale production initiative designed to increase numbers of a weak but potentially recoverable population of spring chinook salmon in the Tucannon River in the State of Washington. BPA has prepared an Environmental Assessment (EA) (DOE/EA-l326) evaluating the proposed project. Based on the analysis in the EA, BPA has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement (EIS) is not required, and BPA is issuing this Finding of No Significant Impact (FONSI).

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.

The significance of multi-slice helical CT multiplanar reconstruction in the diagnoses of laryngeal carcinoma

International Nuclear Information System (INIS)

Li Lin; Luo Dehong; Zhou Chunwu; Zhao Xinming; Jiang Liming; Huang Yao; Jiang Lingxia; Li Jing; Wu Ning

2006-01-01

Objective: To evaluate the significance of multi-slice helical CT with multiplanar reconstruction in laryngeal carcinoma. Methods: Thirty-five patients with laryngeal carcinoma were studied by helical CT, MPR were subsequently done. The lesion extent of the axial image findings, MPR findings and the combined image findings were compared with the pathological results respectively. The data were statistically analyzed. Results: In the evaluation of the anterior commissure, the axial image findings, MPR findings and the combined image findings were 82.9%, 68.6% and 91.4% in accuracy respectively, the results were statistically different (P 0.05). The combined images were superior to the axial images and the MPR images in sensitivity, specificity and accuracy of the lesion extent. Conclusion: The axial images could show the shape, size, extension of the tumor and the lymphadenopathy, MPR images displayed the shape, size and extension roundly and directly, they were the supplement for the axial images. Axial images combined with MPR could improve the accuracy in the diagnoses of laryngeal carcinoma. (authors)

Incorporating an Interactive Statistics Workshop into an Introductory Biology Course-Based Undergraduate Research Experience (CURE) Enhances Students' Statistical Reasoning and Quantitative Literacy Skills.

Science.gov (United States)

Olimpo, Jeffrey T; Pevey, Ryan S; McCabe, Thomas M

2018-01-01

Course-based undergraduate research experiences (CUREs) provide an avenue for student participation in authentic scientific opportunities. Within the context of such coursework, students are often expected to collect, analyze, and evaluate data obtained from their own investigations. Yet, limited research has been conducted that examines mechanisms for supporting students in these endeavors. In this article, we discuss the development and evaluation of an interactive statistics workshop that was expressly designed to provide students with an open platform for graduate teaching assistant (GTA)-mentored data processing, statistical testing, and synthesis of their own research findings. Mixed methods analyses of pre/post-intervention survey data indicated a statistically significant increase in students' reasoning and quantitative literacy abilities in the domain, as well as enhancement of student self-reported confidence in and knowledge of the application of various statistical metrics to real-world contexts. Collectively, these data reify an important role for scaffolded instruction in statistics in preparing emergent scientists to be data-savvy researchers in a globally expansive STEM workforce.

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 ...

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.

Doctorate Education in Canada: Findings from the Survey of Earned Doctorates, 2005/2006. Culture, Tourism and the Centre for Education Statistics. Research Paper. Catalogue no. 81-595-M No. 069

Science.gov (United States)

King, Darren; Eisl-Culkin, Judy; Desjardins, Louise

2008-01-01

"Doctorate Education in Canada: Findings from the Survey of Earned Doctorates, 2005/2006" is the third paper in a series of reports written by the Learning Policy Directorate of Human Resources and Social Development Canada (HRSDC) and the Centre for Education Statistics of Statistics Canada. Each report presents an overview of doctoral…

Are Statistics Labs Worth the Effort?--Comparison of Introductory Statistics Courses Using Different Teaching Methods

Directory of Open Access Journals (Sweden)

Jose H. Guardiola

2010-01-01

Full Text Available This paper compares the academic performance of students in three similar elementary statistics courses taught by the same instructor, but with the lab component differing among the three. One course is traditionally taught without a lab component; the second with a lab component using scenarios and an extensive use of technology, but without explicit coordination between lab and lecture; and the third using a lab component with an extensive use of technology that carefully coordinates the lab with the lecture. Extensive use of technology means, in this context, using Minitab software in the lab section, doing homework and quizzes using MyMathlab ©, and emphasizing interpretation of computer output during lectures. Initially, an online instrument based on Gardner’s multiple intelligences theory, is given to students to try to identify students’ learning styles and intelligence types as covariates. An analysis of covariance is performed in order to compare differences in achievement. In this study there is no attempt to measure difference in student performance across the different treatments. The purpose of this study is to find indications of associations among variables that support the claim that statistics labs could be associated with superior academic achievement in one of these three instructional environments. Also, this study tries to identify individual student characteristics that could be associated with superior academic performance. This study did not find evidence of any individual student characteristics that could be associated with superior achievement. The response variable was computed as percentage of correct answers for the three exams during the semester added together. The results of this study indicate a significant difference across these three different instructional methods, showing significantly higher mean scores for the response variable on students taking the lab component that was carefully coordinated with

75 FR 74131 - Notice of Finding of No Significant Impact for the Washington State Portion of the Pacific...

Science.gov (United States)

2010-11-30

... Environmental Assessment AGENCY: Federal Railroad Administration (FRA), United States Department of... Transportation (WSDOT) prepared a Tier-1 Environmental Assessment (Tier-1 EA) that evaluates the impacts of a... have a significant impact on the quality of the human or natural environment and has issued a Finding...

Environmental Assessment and Finding of No Significant Impact: Kalina Geothermal Demonstration Project Steamboat Springs, Nevada

Energy Technology Data Exchange (ETDEWEB)

N/A

1999-02-22

The Department of Energy (DOE) has prepared an Environmental Assessment (EA) to provide the DOE and other public agency decision makers with the environmental documentation required to take informed discretionary action on the proposed Kalina Geothermal Demonstration project. The EA assesses the potential environmental impacts and cumulative impacts, possible ways to minimize effects associated with partial funding of the proposed project, and discusses alternatives to DOE actions. The DOE will use this EA as a basis for their decision to provide financial assistance to Exergy, Inc. (Exergy), the project applicant. Based on the analysis in the EA, DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human or physical environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an environmental impact statement is not required and DOE is issuing this Finding of No Significant Impact (FONSI).

Infant Statistical Learning

Science.gov (United States)

Saffran, Jenny R.; Kirkham, Natasha Z.

2017-01-01

Perception involves making sense of a dynamic, multimodal environment. In the absence of mechanisms capable of exploiting the statistical patterns in the natural world, infants would face an insurmountable computational problem. Infant statistical learning mechanisms facilitate the detection of structure. These abilities allow the infant to compute across elements in their environmental input, extracting patterns for further processing and subsequent learning. In this selective review, we summarize findings that show that statistical learning is both a broad and flexible mechanism (supporting learning from different modalities across many different content areas) and input specific (shifting computations depending on the type of input and goal of learning). We suggest that statistical learning not only provides a framework for studying language development and object knowledge in constrained laboratory settings, but also allows researchers to tackle real-world problems, such as multilingualism, the role of ever-changing learning environments, and differential developmental trajectories. PMID:28793812

Changes in electrocardiographic findings after closed thoracostomy in patients with spontaneous pneumothorax

Science.gov (United States)

Lee, Wonjae; Lee, Yoonje; Kim, Changsun; Choi, Hyuk Joong; Kang, Bossng; Lim, Tae Ho; Oh, Jaehoon; Kang, Hyunggoo; Shin, Junghun

2017-01-01

Objective We aimed to describe electrocardiographic (ECG) findings in spontaneous pneumothorax patients before and after closed thoracostomy. Methods This is a retrospective study which included patients with spontaneous pneumothorax who presented to an emergency department of a tertiary urban hospital from February 2005 to March 2015. The primary outcome was a difference in ECG findings between before and after closed thoracostomy. We specifically investigated the following ECG elements: PR, QRS, QTc, axis, ST segments, and R waves in each lead. The secondary outcomes were change in ST segment in any lead and change in axis after closed thoracostomy. Results There were two ECG elements which showed statistically significant difference after thoracostomy. With right pneumothorax volume of greater than 80%, QTc and the R waves in aVF and V5 significantly changed after thoracostomy. With left pneumothorax volume between 31% and 80%, the ST segment in V2 and the R wave in V1 significantly changed after thoracostomy. However, majority of ECG elements did not show statistically significant alteration after thoracostomy. Conclusion We found only minor changes in ECG after closed thoracostomy in spontaneous pneumothorax patients. PMID:28435901

Quantifying scenarios to check statistical procedures

International Nuclear Information System (INIS)

Beetle, T.M.

1976-01-01

Ways of diverting nuclear material are presented in a form that reflects the effects of the diversions on a select set of statistical accounting procedures. Twelve statistics are examined for changes in mean values under sixty diversion scenarios. Several questions about the statistics are answered using a table of quantification results. Findings include a smallest, proper subset of the set of statistics which has one or more changed mean values under each of the diversion scenarios

75 FR 17161 - Job Corps: Preliminary Finding of No Significant Impact (FONSI) for the Installation of a Small...

Science.gov (United States)

2010-04-05

... DEPARTMENT OF LABOR Office of the Secretary Job Corps: Preliminary Finding of No Significant Impact (FONSI) for the Installation of a Small Wind Turbine at the Pine Ridge Job Corps Center Located at... the Pine Ridge Job Corps Center, 15710 Highway 385, Chadron, NE 69337. SUMMARY: Pursuant to the...

The relationship between procrastination, learning strategies and statistics anxiety among Iranian college students: a canonical correlation analysis.

Science.gov (United States)

Vahedi, Shahrum; Farrokhi, Farahman; Gahramani, Farahnaz; Issazadegan, Ali

2012-01-01

Approximately 66-80%of graduate students experience statistics anxiety and some researchers propose that many students identify statistics courses as the most anxiety-inducing courses in their academic curriculums. As such, it is likely that statistics anxiety is, in part, responsible for many students delaying enrollment in these courses for as long as possible. This paper proposes a canonical model by treating academic procrastination (AP), learning strategies (LS) as predictor variables and statistics anxiety (SA) as explained variables. A questionnaire survey was used for data collection and 246-college female student participated in this study. To examine the mutually independent relations between procrastination, learning strategies and statistics anxiety variables, a canonical correlation analysis was computed. Findings show that two canonical functions were statistically significant. The set of variables (metacognitive self-regulation, source management, preparing homework, preparing for test and preparing term papers) helped predict changes of statistics anxiety with respect to fearful behavior, Attitude towards math and class, Performance, but not Anxiety. These findings could be used in educational and psychological interventions in the context of statistics anxiety reduction.

Finding of No Significant Impact, proposed remediation of the Maybell Uranium Mill Processing Site, Maybell, Colorado

International Nuclear Information System (INIS)

1995-01-01

The U.S. Department of Energy (DOE) has prepared an environmental assessment (EA) (DOE/EA-0347) on the proposed surface remediation of the Maybell uranium mill processing site in Moffat County, Colorado. The mill site contains radioactively contaminated materials from processing uranium ore that would be stabilized in place at the existing tailings pile location. Based on the analysis in the EA, DOE has determined that the proposed action does not constitute a major federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969, Public Law 91-190 (42 U.S.C. section 4321 et seq.), as amended. Therefore, preparation of an environmental impact statement is not required and DOE is issuing this Finding of No Significant Impact (FONSI)

Basics of modern mathematical statistics

CERN Document Server

Spokoiny, Vladimir

2015-01-01

This textbook provides a unified and self-contained presentation of the main approaches to and ideas of mathematical statistics. It collects the basic mathematical ideas and tools needed as a basis for more serious studies or even independent research in statistics. The majority of existing textbooks in mathematical statistics follow the classical asymptotic framework. Yet, as modern statistics has changed rapidly in recent years, new methods and approaches have appeared. The emphasis is on finite sample behavior, large parameter dimensions, and model misspecifications. The present book provides a fully self-contained introduction to the world of modern mathematical statistics, collecting the basic knowledge, concepts and findings needed for doing further research in the modern theoretical and applied statistics. This textbook is primarily intended for graduate and postdoc students and young researchers who are interested in modern statistical methods.

Incorporating an Interactive Statistics Workshop into an Introductory Biology Course-Based Undergraduate Research Experience (CURE) Enhances Students’ Statistical Reasoning and Quantitative Literacy Skills †

Science.gov (United States)

Olimpo, Jeffrey T.; Pevey, Ryan S.; McCabe, Thomas M.

2018-01-01

Course-based undergraduate research experiences (CUREs) provide an avenue for student participation in authentic scientific opportunities. Within the context of such coursework, students are often expected to collect, analyze, and evaluate data obtained from their own investigations. Yet, limited research has been conducted that examines mechanisms for supporting students in these endeavors. In this article, we discuss the development and evaluation of an interactive statistics workshop that was expressly designed to provide students with an open platform for graduate teaching assistant (GTA)-mentored data processing, statistical testing, and synthesis of their own research findings. Mixed methods analyses of pre/post-intervention survey data indicated a statistically significant increase in students’ reasoning and quantitative literacy abilities in the domain, as well as enhancement of student self-reported confidence in and knowledge of the application of various statistical metrics to real-world contexts. Collectively, these data reify an important role for scaffolded instruction in statistics in preparing emergent scientists to be data-savvy researchers in a globally expansive STEM workforce. PMID:29904549

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

75 FR 27583 - Job Corps: Final Finding of No Significant Impact (FONSI) for Small Vertical Wind Turbine and...

Science.gov (United States)

2010-05-17

... CFR 11.11(d), gives final notice of the proposed construction of a small vertical axis wind turbine... (FONSI) for Small Vertical Wind Turbine and Solar Installation at the Paul Simon Job Corps Center Located... impact. This notice serves as the Final Finding of No Significant Impact (FONSI) for Small Vertical Wind...

75 FR 29365 - Job Corps: Final Finding of No Significant Impact (FONSI) for Small Wind Turbine Installation at...

Science.gov (United States)

2010-05-25

... (FONSI) for Small Wind Turbine Installation at the Pine Ridge Job Corps Center Located at 15710 Highway... Finding of No Significant Impact (FONSI) for Small Wind Turbine Installation at the Pine Ridge Job Corps....11(d), gives final notice of the proposed construction of a small wind turbine at the Pine Ridge Job...

The earth is flat (p > 0.05: significance thresholds and the crisis of unreplicable research

Directory of Open Access Journals (Sweden)

Valentin Amrhein

2017-07-01

Full Text Available The widespread use of ‘statistical significance’ as a license for making a claim of a scientific finding leads to considerable distortion of the scientific process (according to the American Statistical Association. We review why degrading p-values into ‘significant’ and ‘nonsignificant’ contributes to making studies irreproducible, or to making them seem irreproducible. A major problem is that we tend to take small p-values at face value, but mistrust results with larger p-values. In either case, p-values tell little about reliability of research, because they are hardly replicable even if an alternative hypothesis is true. Also significance (p ≤ 0.05 is hardly replicable: at a good statistical power of 80%, two studies will be ‘conflicting’, meaning that one is significant and the other is not, in one third of the cases if there is a true effect. A replication can therefore not be interpreted as having failed only because it is nonsignificant. Many apparent replication failures may thus reflect faulty judgment based on significance thresholds rather than a crisis of unreplicable research. Reliable conclusions on replicability and practical importance of a finding can only be drawn using cumulative evidence from multiple independent studies. However, applying significance thresholds makes cumulative knowledge unreliable. One reason is that with anything but ideal statistical power, significant effect sizes will be biased upwards. Interpreting inflated significant results while ignoring nonsignificant results will thus lead to wrong conclusions. But current incentives to hunt for significance lead to selective reporting and to publication bias against nonsignificant findings. Data dredging, p-hacking, and publication bias should be addressed by removing fixed significance thresholds. Consistent with the recommendations of the late Ronald Fisher, p-values should be interpreted as graded measures of the strength of evidence

Statistical tests for power-law cross-correlated processes

Science.gov (United States)

Podobnik, Boris; Jiang, Zhi-Qiang; Zhou, Wei-Xing; Stanley, H. Eugene

2011-12-01

For stationary time series, the cross-covariance and the cross-correlation as functions of time lag n serve to quantify the similarity of two time series. The latter measure is also used to assess whether the cross-correlations are statistically significant. For nonstationary time series, the analogous measures are detrended cross-correlations analysis (DCCA) and the recently proposed detrended cross-correlation coefficient, ρDCCA(T,n), where T is the total length of the time series and n the window size. For ρDCCA(T,n), we numerically calculated the Cauchy inequality -1≤ρDCCA(T,n)≤1. Here we derive -1≤ρDCCA(T,n)≤1 for a standard variance-covariance approach and for a detrending approach. For overlapping windows, we find the range of ρDCCA within which the cross-correlations become statistically significant. For overlapping windows we numerically determine—and for nonoverlapping windows we derive—that the standard deviation of ρDCCA(T,n) tends with increasing T to 1/T. Using ρDCCA(T,n) we show that the Chinese financial market's tendency to follow the U.S. market is extremely weak. We also propose an additional statistical test that can be used to quantify the existence of cross-correlations between two power-law correlated time series.

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.

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

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

Computational statistics handbook with Matlab

CERN Document Server

Martinez, Wendy L

2007-01-01

Prefaces Introduction What Is Computational Statistics? An Overview of the Book Probability Concepts Introduction Probability Conditional Probability and Independence Expectation Common Distributions Sampling Concepts Introduction Sampling Terminology and Concepts Sampling Distributions Parameter Estimation Empirical Distribution Function Generating Random Variables Introduction General Techniques for Generating Random Variables Generating Continuous Random Variables Generating Discrete Random Variables Exploratory Data Analysis Introduction Exploring Univariate Data Exploring Bivariate and Trivariate Data Exploring Multidimensional Data Finding Structure Introduction Projecting Data Principal Component Analysis Projection Pursuit EDA Independent Component Analysis Grand Tour Nonlinear Dimensionality Reduction Monte Carlo Methods for Inferential Statistics Introduction Classical Inferential Statistics Monte Carlo Methods for Inferential Statist...

Whose statistical reasoning is facilitated by a causal structure intervention?

Science.gov (United States)

McNair, Simon; Feeney, Aidan

2015-02-01

People often struggle when making Bayesian probabilistic estimates on the basis of competing sources of statistical evidence. Recently, Krynski and Tenenbaum (Journal of Experimental Psychology: General, 136, 430-450, 2007) proposed that a causal Bayesian framework accounts for peoples' errors in Bayesian reasoning and showed that, by clarifying the causal relations among the pieces of evidence, judgments on a classic statistical reasoning problem could be significantly improved. We aimed to understand whose statistical reasoning is facilitated by the causal structure intervention. In Experiment 1, although we observed causal facilitation effects overall, the effect was confined to participants high in numeracy. We did not find an overall facilitation effect in Experiment 2 but did replicate the earlier interaction between numerical ability and the presence or absence of causal content. This effect held when we controlled for general cognitive ability and thinking disposition. Our results suggest that clarifying causal structure facilitates Bayesian judgments, but only for participants with sufficient understanding of basic concepts in probability and statistics.

Mycoplasma hominis: an incidental but significant finding by routine bacteriological culture

DEFF Research Database (Denmark)

Gertsen, Jan Berg; Schønheyder, Henrik Carl

2009-01-01

bacteriological culture during a 4-year period. Methods: Dpt. of Clinical Microbiology, Aalborg Hospital serves a population of 0.5 mio. Aerobic bacteriologic cultures are routinely carried out on 5% horse blood agar and chocolate agar (SSI Diagnostika, DK) at 35 °C in 5% CO2. The finding of translucent, pinpoint...... not respond to surgical drainage of the abscesses (if present) and prolonged empirical intravenous therapy with a β-lactam antibiotic and metronidazole (median 9 days). The tentative diagnosis of M. hominis prompted a change of antibiotic therapy to either moxifloxacin or clindamycin which was followed...... by resolution of symptoms and normalisation of CRP (median 9 days). Conclusion: M. hominis is a rare finding by prolonged incubation of conventional blood agar. A pathogenic role of M. hominis was supported by the lack of clinical response to surgical drainage and prolonged empirical antibiotic therapy...

Characterization of Change and Significance for Clinical Findings in Radiology Reports Through Natural Language Processing.

Science.gov (United States)

Hassanpour, Saeed; Bay, Graham; Langlotz, Curtis P

2017-06-01

We built a natural language processing (NLP) method to automatically extract clinical findings in radiology reports and characterize their level of change and significance according to a radiology-specific information model. We utilized a combination of machine learning and rule-based approaches for this purpose. Our method is unique in capturing different features and levels of abstractions at surface, entity, and discourse levels in text analysis. This combination has enabled us to recognize the underlying semantics of radiology report narratives for this task. We evaluated our method on radiology reports from four major healthcare organizations. Our evaluation showed the efficacy of our method in highlighting important changes (accuracy 99.2%, precision 96.3%, recall 93.5%, and F1 score 94.7%) and identifying significant observations (accuracy 75.8%, precision 75.2%, recall 75.7%, and F1 score 75.3%) to characterize radiology reports. This method can help clinicians quickly understand the key observations in radiology reports and facilitate clinical decision support, review prioritization, and disease surveillance.

The Relationship between Test Anxiety and Academic Performance of Students in Vital Statistics Course

Directory of Open Access Journals (Sweden)

Shirin Iranfar

2013-12-01

Full Text Available Introduction: Test anxiety is a common phenomenon among students and is one of the problems of educational system. The present study was conducted to investigate the test anxiety in vital statistics course and its association with academic performance of students at Kermanshah University of Medical Sciences. This study was descriptive-analytical and the study sample included the students studying in nursing and midwifery, paramedicine and health faculties that had taken vital statistics course and were selected through census method. Sarason questionnaire was used to analyze the test anxiety. Data were analyzed by descriptive and inferential statistics. The findings indicated no significant correlation between test anxiety and score of vital statistics course.

The diagnostic significance of clinical and radiological findings in osteogenesis imperfection

International Nuclear Information System (INIS)

Xu Deyong; Xu Zushan; Shen Qijie

1997-01-01

Purpose: To define the diagnostic criteria of osteogenesis imperfection. Materials and methods: The clinical and radiologic manifestations of 68 patients with osteogenesis imperfection were studied retrospectively. Results: (1) A generalized decrease in osseous density (osteoporosis or osteopenia) with abnormal fragility of bone (68 cases). (2) Blue sclera (61 cases). (3) Dentinogenesis imperfection with opalescent bluish-gray tint (49 cases). (4) Progressive hearing loss (prior to the age of 40 years)-premature otosclerosis (38 cases). Other abnormalities such as abnormal contour and structure (68 cases), growth retardation (49 cases), episodic diaphoresis (24 cases), with abnormal temperature regulation (16 cases), hyperplastic scars (11 cases) and tendency of subcutaneous bruise (6 cases), all these were not characteristic features. Conclusion: Among all clinical and radiological findings, osteopenia with abnormal fragility of bone; blue sclera dentinogenesis imperfection with opalescent bluish-gray tint and premature otosclerosis are the most common and characteristic findings which can be taken as the diagnostic criteria of osteogenesis imperfection

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.

Imaging findings and significance of deep neck space infection

International Nuclear Information System (INIS)

Zhuang Qixin; Gu Yifeng; Du Lianjun; Zhu Lili; Pan Yuping; Li Minghua; Yang Shixun; Shang Kezhong; Yin Shankai

2004-01-01

Objective: To study the imaging appearance of deep neck space cellulitis and abscess and to evaluate the diagnostic criteria of deep neck space infection. Methods: CT and MRI findings of 28 cases with deep neck space infection proved by clinical manifestation and pathology were analyzed, including 11 cases of retropharyngeal space, 5 cases of parapharyngeal space infection, 4 cases of masticator space infection, and 8 cases of multi-space infection. Results: CT and MRI could display the swelling of the soft tissues and displacement, reduction, or disappearance of lipoid space in the cellulitis. In inflammatory tissues, MRI imaging demonstrated hypointense or isointense signal on T 1 WI, and hyperintense signal changes on T 2 WI. In abscess, CT could display hypodensity in the center and boundary enhancement of the abscess. MRI could display obvious hyperintense signal on T 2 WI and boundary enhancement. Conclusion: CT and MRI could provide useful information for deep neck space cellulitis and abscess

Planck 2013 results. XXIII. Isotropy and Statistics of the CMB

CERN Document Server

Ade, P.A.R.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Bartlett, J.G.; Bartolo, N.; Battaner, E.; Battye, R.; Benabed, K.; Benoit, A.; Benoit-Levy, A.; Bernard, J.P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J.J.; Bonaldi, A.; Bonavera, L.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R.C.; Cardoso, J.F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.R.; Chiang, L.Y.; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Couchot, F.; Coulais, A.; Crill, B.P.; Cruz, M.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.M.; Desert, F.X.; Diego, J.M.; Dole, H.; Donzelli, S.; Dore, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Ensslin, T.A.; Eriksen, H.K.; Fantaye, Y.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Frommert, M.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Heraud, Y.; Gonzalez-Nuevo, J.; Gorski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, M.; Hansen, F.K.; Hanson, D.; Harrison, D.; Helou, G.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Jaffe, T.R.; Jaffe, A.H.; Jones, W.C.; Juvela, M.; Keihanen, E.; Keskitalo, R.; Kim, J.; Kisner, T.S.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lahteenmaki, A.; Lamarre, J.M.; Lasenby, A.; Laureijs, R.J.; Lawrence, C.R.; Leahy, J.P.; Leonardi, R.; Leroy, C.; Lesgourgues, J.; Liguori, M.; Lilje, P.B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lubin, P.M.; Macias-Perez, J.F.; Maffei, B.; Maino, D.; Mandolesi, N.; Mangilli, A.; Marinucci, D.; Maris, M.; Marshall, D.J.; Martin, P.G.; Martinez-Gonzalez, E.; Masi, S.; Matarrese, S.; Matthai, F.; Mazzotta, P.; McEwen, J.D.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mikkelsen, K.; Mitra, S.; Miville-Deschenes, M.A.; Molinari, D.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Norgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Peiris, H.V.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Pogosyan, D.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G.W.; Prezeau, G.; Prunet, S.; Puget, J.L.; Rachen, J.P.; Rath, C.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rotti, A.; Roudier, G.; Rubino-Martin, J.A.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M.D.; Shellard, E.P.S.; Souradeep, T.; Spencer, L.D.; Starck, J.L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sureau, F.; Sutter, P.; Sutton, D.; Suur-Uski, A.S.; Sygnet, J.F.; Tauber, J.A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Turler, M.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Varis, J.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L.A.; Wandelt, B.D.; Wehus, I.K.; White, M.; Wilkinson, A.; Yvon, D.; Zacchei, A.; Zonca, A.

2014-01-01

The two fundamental assumptions of the standard cosmological model - that the initial fluctuations are statistically isotropic and Gaussian - are rigorously tested using maps of the cosmic microwave background (CMB) anisotropy from the Planck satellite. Deviations from isotropy have been found and demonstrated to be robust against component separation algorithm, mask choice and frequency dependence. Many of these anomalies were previously observed in the WMAP data, and are now confirmed at similar levels of significance (about 3 sigma). However, we find little evidence for non-Gaussianity, with the exception of a few statistical signatures that seem to be associated with specific anomalies. In particular, we find that the quadrupole-octopole alignment is also connected to a low observed variance of the CMB signal. A power asymmetry is now found to persist to scales corresponding to about l=600, and can be described in the low-l regime by a phenomenological dipole modulation model. However, any primordial powe...

Practical Statistics for Environmental and Biological Scientists

CERN Document Server

Townend, John

2012-01-01

All students and researchers in environmental and biological sciences require statistical methods at some stage of their work. Many have a preconception that statistics are difficult and unpleasant and find that the textbooks available are difficult to understand. Practical Statistics for Environmental and Biological Scientists provides a concise, user-friendly, non-technical introduction to statistics. The book covers planning and designing an experiment, how to analyse and present data, and the limitations and assumptions of each statistical method. The text does not refer to a specific comp

Statistical principles for prospective study protocols:

DEFF Research Database (Denmark)

Christensen, Robin; Langberg, Henning

2012-01-01

In the design of scientific studies it is essential to decide on which scientific questions one aims to answer, just as it is important to decide on the correct statistical methods to use to answer these questions. The correct use of statistical methods is crucial in all aspects of research...... to quantify relationships in data. Despite an increased focus on statistical content and complexity of biomedical research these topics remain difficult for most researchers. Statistical methods enable researchers to condense large spreadsheets with data into means, proportions, and difference between means...... the statistical principles for trial protocols in terms of design, analysis, and reporting of findings....

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.

Multimodal integration in statistical learning

DEFF Research Database (Denmark)

Mitchell, Aaron; Christiansen, Morten Hyllekvist; Weiss, Dan

2014-01-01

, we investigated the ability of adults to integrate audio and visual input during statistical learning. We presented learners with a speech stream synchronized with a video of a speaker’s face. In the critical condition, the visual (e.g., /gi/) and auditory (e.g., /mi/) signals were occasionally...... facilitated participants’ ability to segment the speech stream. Our results therefore demonstrate that participants can integrate audio and visual input to perceive the McGurk illusion during statistical learning. We interpret our findings as support for modality-interactive accounts of statistical learning.......Recent advances in the field of statistical learning have established that learners are able to track regularities of multimodal stimuli, yet it is unknown whether the statistical computations are performed on integrated representations or on separate, unimodal representations. In the present study...

The Relationship Between Procrastination, Learning Strategies and Statistics Anxiety Among Iranian College Students: A Canonical Correlation Analysis

Science.gov (United States)

Vahedi, Shahrum; Farrokhi, Farahman; Gahramani, Farahnaz; Issazadegan, Ali

2012-01-01

Objective: Approximately 66-80%of graduate students experience statistics anxiety and some researchers propose that many students identify statistics courses as the most anxiety-inducing courses in their academic curriculums. As such, it is likely that statistics anxiety is, in part, responsible for many students delaying enrollment in these courses for as long as possible. This paper proposes a canonical model by treating academic procrastination (AP), learning strategies (LS) as predictor variables and statistics anxiety (SA) as explained variables. Methods: A questionnaire survey was used for data collection and 246-college female student participated in this study. To examine the mutually independent relations between procrastination, learning strategies and statistics anxiety variables, a canonical correlation analysis was computed. Results: Findings show that two canonical functions were statistically significant. The set of variables (metacognitive self-regulation, source management, preparing homework, preparing for test and preparing term papers) helped predict changes of statistics anxiety with respect to fearful behavior, Attitude towards math and class, Performance, but not Anxiety. Conclusion: These findings could be used in educational and psychological interventions in the context of statistics anxiety reduction. PMID:24644468

Finding of no significant impact proposed remedial action at two uranium processing sites near Slick Rock, Colorado

International Nuclear Information System (INIS)

1994-01-01

The U.S. Department of Energy (DOE) has prepared an environmental assessment (EA) (DOE/EA-0339) of the proposed remedial action at two uranium processing sites near Slick Rock in San Miguel County, Colorado. These sites contain radioactively contaminated materials that would be removed and stabilized at a remote location. Based on the information and analyses in the EA, the DOE has determined that the proposed action does not constitute a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969 (42 U.S.C. 4321 et seq.), as amended. Therefore, preparation of an environmental impact statement is not required, and the DOE is issuing this Finding of No Significant Impact (ONSI)

Do positive MRI findings in the lumbar spine predict future seeking care for low back pain in young teenagers?

DEFF Research Database (Denmark)

Kjær, Per; Leboeuf-Yde, Charlotte; Korsholm, Lars

Background: In MRI studies lumbar disk degeneration and endplate changes have been found in children and adolescents. Such MRI findings appear to be more strongly associated with LBP than in adults. However, this knowledge is mainly based on cross-sectional studies from which no inferences regarded......, nucleus form, annular tears, high intensity zones, bulging, herniation, nerve root compression, endplate changes, Modic changes, and spondylolisthesis). Associations were sought through logistic regression at each lumbar level for boys and girls separately. Statistically significant results were presented......, and annular tears and bulging at L4. Moderate predictors included reduced signal L1 and L4, disk herniation and nerve root compression L4. Other levels and findings showed no statistically significant associations. Interestingly, the areas with the fewest findings showed the strongest associations to seeking...

New significance test methods for Fourier analysis of geophysical time series

Directory of Open Access Journals (Sweden)

Z. Zhang

2011-09-01

Full Text Available When one applies the discrete Fourier transform to analyze finite-length time series, discontinuities at the data boundaries will distort its Fourier power spectrum. In this paper, based on a rigid statistics framework, we present a new significance test method which can extract the intrinsic feature of a geophysical time series very well. We show the difference in significance level compared with traditional Fourier tests by analyzing the Arctic Oscillation (AO and the Nino3.4 time series. In the AO, we find significant peaks at about 2.8, 4.3, and 5.7 yr periods and in Nino3.4 at about 12 yr period in tests against red noise. These peaks are not significant in traditional tests.

Ultrasonographic Findings of Papillary Thyroid Cancer with or without Hashimoto's Thyroiditis

International Nuclear Information System (INIS)

Park, Jun Young; Lee, Tae Hyun; Park, Dong Hee

2010-01-01

This study was designed to compare the ultrasonographic features of papillary thyroid carcinoma with and without Hashimoto's thyroiditis. This retrospective study included 190 patients with papillary thyroid carcinoma which was proven by neck surgery. The difference in the ultrasonographic findings between papillary thyroid carcinoma with Hashimoto's thyroiditis and papillary thyroid carcinoma without Hashimoto's thyroiditis were calculated statistically. Hashimoto's thyroiditis was diagnosed in 61 of 190 patients following neck surgery. The incidence of coexisting papillary thyroid carcinoma with Hashimoto's thyroiditis was significantly higher in women (p=0.0026). In addition, the frequency of macrocalcification in patients with Hashimoto's thyroiditis was also significantly higher (p=0.0009). Conversely,other ultrasonographic findings including the shape, margin, echogenicity and calcifications, for patients with papillary thyroid carcinoma with Hashimoto's thyroiditis and papillary thyroid carcinoma without Hashimoto's thyroiditis, were not statistically significant. We also found that patients with Hashimoto's thyroiditis who showed no calcification on ultrasonography tended not to detect the papillary carcinoma at a higher frequency. On ultrasonography, macrocalcifications occurred more frequently in patients with Hashimoto's thyroiditis than those without Hashimoto's thyroiditis. Malignant thyroid nodules without calcifications in patients with Hashimoto's thyroiditis more often could not be detected. Therefore, it is important carefully examine patients with Hashimoto's thyroiditis

Exoplanets, Exo-Solar Life, and Human Significance

Science.gov (United States)

Wiseman, Jennifer

2011-01-01

With the recent detection of over 500 extrasolar planets, the existence of "other worlds", perhaps even other Earths, is no longer in the realm of science fiction. The study of exoplanets rapidly moved from an activity on the fringe of astronomy to one of the highest priorities of the world's astronomical programs. Actual images of extrasolar planets were revealed over the past two years for the first time. NASA's Hubble Space Telescope is already characterizing the atmospheres of Jupiter-like planets, in other systems. And the recent launch of the NASA Kepler space telescope is enabling the first statistical assessment of how common solar systems like our own really are. As we begin to characterize these "other worlds" and assess their habitability, the question of the significance and uniqueness of life on Earth will impact our society as never before. I will provide a comprehensive overview of the techniques and status of exoplanet detection, followed by reflections as to the societal impact of finding out that Earths are common, or rare. Will finding other potentially habitable planets create another "Copernican Revolution"? Will perceptions of the significance of life on Earth change when we find other Earth-like planets? I will discuss the plans of the scientific community for future telescopes that will be abe to survey our solar neighborhood for Earth-like planets, study their atmospheres, and search for biological signs of life.

Identical particles, exotic statistics and braid groups

International Nuclear Information System (INIS)

Imbo, T.D.; Sudarshan, E.C.G.; Shah Imbo, C.

1990-01-01

The inequivalent quantizations of a system of n identical particles on a manifold M, dim M≥2, are in 1-1 correspondence with irreducible unitary representations of the braid group B n (M). The notion of the statistics of the particles is made precise. We give various examples where all the possible statistics for the system are determined, and find instances where the particles obey statistics different from the well-studied Bose, Fermi para- and θ-statistics. (orig.)

Pairwise contact energy statistical potentials can help to find probability of point mutations.

Science.gov (United States)

Saravanan, K M; Suvaithenamudhan, S; Parthasarathy, S; Selvaraj, S

2017-01-01

To adopt a particular fold, a protein requires several interactions between its amino acid residues. The energetic contribution of these residue-residue interactions can be approximated by extracting statistical potentials from known high resolution structures. Several methods based on statistical potentials extracted from unrelated proteins are found to make a better prediction of probability of point mutations. We postulate that the statistical potentials extracted from known structures of similar folds with varying sequence identity can be a powerful tool to examine probability of point mutation. By keeping this in mind, we have derived pairwise residue and atomic contact energy potentials for the different functional families that adopt the (α/β) 8 TIM-Barrel fold. We carried out computational point mutations at various conserved residue positions in yeast Triose phosphate isomerase enzyme for which experimental results are already reported. We have also performed molecular dynamics simulations on a subset of point mutants to make a comparative study. The difference in pairwise residue and atomic contact energy of wildtype and various point mutations reveals probability of mutations at a particular position. Interestingly, we found that our computational prediction agrees with the experimental studies of Silverman et al. (Proc Natl Acad Sci 2001;98:3092-3097) and perform better prediction than i Mutant and Cologne University Protein Stability Analysis Tool. The present work thus suggests deriving pairwise contact energy potentials and molecular dynamics simulations of functionally important folds could help us to predict probability of point mutations which may ultimately reduce the time and cost of mutation experiments. Proteins 2016; 85:54-64. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Renal duplex Doppler ultrasound findings in diabetics

International Nuclear Information System (INIS)

Shim, Hyang Yee; Kim, Young Geun; Kook, Cheol Keu; Yoon, Chong Hyun; Lee, Shin Hyung; Lee, Chang Joon

1993-01-01

The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

Renal duplex Doppler ultrasound findings in diabetics

Energy Technology Data Exchange (ETDEWEB)

Shim, Hyang Yee; Kim, Young Geun; Kook, Cheol Keu; Yoon, Chong Hyun; Lee, Shin Hyung; Lee, Chang Joon [National Medical Center, Seoul (Korea, Republic of)

1993-12-15

The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

Willingness to share research data is related to the strength of the evidence and the quality of reporting of statistical results.

Directory of Open Access Journals (Sweden)

Jelte M Wicherts

Full Text Available BACKGROUND: The widespread reluctance to share published research data is often hypothesized to be due to the authors' fear that reanalysis may expose errors in their work or may produce conclusions that contradict their own. However, these hypotheses have not previously been studied systematically. METHODS AND FINDINGS: We related the reluctance to share research data for reanalysis to 1148 statistically significant results reported in 49 papers published in two major psychology journals. We found the reluctance to share data to be associated with weaker evidence (against the null hypothesis of no effect and a higher prevalence of apparent errors in the reporting of statistical results. The unwillingness to share data was particularly clear when reporting errors had a bearing on statistical significance. CONCLUSIONS: Our findings on the basis of psychological papers suggest that statistical results are particularly hard to verify when reanalysis is more likely to lead to contrasting conclusions. This highlights the importance of establishing mandatory data archiving policies.

Identifying Statistical Dependence in Genomic Sequences via Mutual Information Estimates

Directory of Open Access Journals (Sweden)

Wojciech Szpankowski

2007-12-01

Full Text Available Questions of understanding and quantifying the representation and amount of information in organisms have become a central part of biological research, as they potentially hold the key to fundamental advances. In this paper, we demonstrate the use of information-theoretic tools for the task of identifying segments of biomolecules (DNA or RNA that are statistically correlated. We develop a precise and reliable methodology, based on the notion of mutual information, for finding and extracting statistical as well as structural dependencies. A simple threshold function is defined, and its use in quantifying the level of significance of dependencies between biological segments is explored. These tools are used in two specific applications. First, they are used for the identification of correlations between different parts of the maize zmSRp32 gene. There, we find significant dependencies between the 5′ untranslated region in zmSRp32 and its alternatively spliced exons. This observation may indicate the presence of as-yet unknown alternative splicing mechanisms or structural scaffolds. Second, using data from the FBI's combined DNA index system (CODIS, we demonstrate that our approach is particularly well suited for the problem of discovering short tandem repeats—an application of importance in genetic profiling.

Evaluation of Tl-201 SPECT imaging findings in prostate cancer

Directory of Open Access Journals (Sweden)

Sinem Ozyurt

2015-07-01

Full Text Available Objectives: To compare with histopathological findings the findings of prostate cancer imaging by SPECT method using Tl-201 as a tumor seeking agent. Methods: The study comprised 59 patients (age range 51-79 years, mean age 65.3 ± 6.8 years who were planned to have transrectal ultrasonography (TRUS-guided biopsies due to suspicion of prostate cancer between April 2011 and September 2011. Early planar, late planar and SPECT images were obtained for all patients. Scintigraphic evaluation was made in relation to uptake presence and patterns in the visual assessment and to Tumor/Background (T/Bg ratios for both planar and SPECT images in the quantitative assessment. Histopathological findings were compatible with benign etiology in 36 (61% patients and malign etiology in 23 (39% patients. Additionally, comparisons were made to evaluate the relationships between uptake patterns,total PSA values and Gleason scores. Results: A statistically significant difference was found between the benign and malignant groups in terms of uptake in planar and SPECT images and T/Bg ratios and PSA values. No statistically significant difference was found between uptake patterns of planar and SPECT images and Gleason scores in the malignant group. Conclusions: SPECT images were superior to planar images in the comparative assessment. Tl-201 SPECT imaging can provide an additional contribution to clinical practice in the diagnosis of prostate cancer and it can be used in selected patients.

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.

Las pruebas de significación estadística en tres revistas biomédicas: una revisión crítica Tests of statistical significance in three biomedical journals: a critical review

Directory of Open Access Journals (Sweden)

Madelaine Sarria Castro

2004-05-01

Comprehensive General Medicine], Revista Panamericana de Salud Pública/Pan American Journal of Public Health, and Medicina Clínica [Clinical Medicine] (which is published in Spain. RESULTS: In the three journals that were reviewed various shortcomings were found in their use of hypothesis tests based on P values and in the limited use of new tools that have been suggested for use in their place: confidence intervals (CIs and Bayesian inference. The basic findings of our research were: minimal use of CIs, as either a complement to significance tests or as the only statistical tool; mentions of a small sample size as a possible explanation for the lack of statistical significance; a predominant use of rigid alpha values; a lack of uniformity in the presentation of results; and improper reference in the research conclusions to the results of hypothesis tests. CONCLUSIONS: Our results indicate the lack of compliance by authors and editors with accepted standards for the use of tests of statistical significance. The findings also highlight that the stagnant use of these tests continues to be a common practice in the scientific literature.

Death Certification Errors and the Effect on Mortality Statistics.

Science.gov (United States)

McGivern, Lauri; Shulman, Leanne; Carney, Jan K; Shapiro, Steven; Bundock, Elizabeth

Errors in cause and manner of death on death certificates are common and affect families, mortality statistics, and public health research. The primary objective of this study was to characterize errors in the cause and manner of death on death certificates completed by non-Medical Examiners. A secondary objective was to determine the effects of errors on national mortality statistics. We retrospectively compared 601 death certificates completed between July 1, 2015, and January 31, 2016, from the Vermont Electronic Death Registration System with clinical summaries from medical records. Medical Examiners, blinded to original certificates, reviewed summaries, generated mock certificates, and compared mock certificates with original certificates. They then graded errors using a scale from 1 to 4 (higher numbers indicated increased impact on interpretation of the cause) to determine the prevalence of minor and major errors. They also compared International Classification of Diseases, 10th Revision (ICD-10) codes on original certificates with those on mock certificates. Of 601 original death certificates, 319 (53%) had errors; 305 (51%) had major errors; and 59 (10%) had minor errors. We found no significant differences by certifier type (physician vs nonphysician). We did find significant differences in major errors in place of death ( P statistics. Surveillance and certifier education must expand beyond local and state efforts. Simplifying and standardizing underlying literal text for cause of death may improve accuracy, decrease coding errors, and improve national mortality statistics.

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.

Probability, statistics, and associated computing techniques

International Nuclear Information System (INIS)

James, F.

1983-01-01

This chapter attempts to explore the extent to which it is possible for the experimental physicist to find optimal statistical techniques to provide a unique and unambiguous quantitative measure of the significance of raw data. Discusses statistics as the inverse of probability; normal theory of parameter estimation; normal theory (Gaussian measurements); the universality of the Gaussian distribution; real-life resolution functions; combination and propagation of uncertainties; the sum or difference of 2 variables; local theory, or the propagation of small errors; error on the ratio of 2 discrete variables; the propagation of large errors; confidence intervals; classical theory; Bayesian theory; use of the likelihood function; the second derivative of the log-likelihood function; multiparameter confidence intervals; the method of MINOS; least squares; the Gauss-Markov theorem; maximum likelihood for uniform error distribution; the Chebyshev fit; the parameter uncertainties; the efficiency of the Chebyshev estimator; error symmetrization; robustness vs. efficiency; testing of hypotheses (e.g., the Neyman-Pearson test); goodness-of-fit; distribution-free tests; comparing two one-dimensional distributions; comparing multidimensional distributions; and permutation tests for comparing two point sets

Experimental statistics for biological sciences.

Science.gov (United States)

Bang, Heejung; Davidian, Marie

2010-01-01

In this chapter, we cover basic and fundamental principles and methods in statistics - from "What are Data and Statistics?" to "ANOVA and linear regression," which are the basis of any statistical thinking and undertaking. Readers can easily find the selected topics in most introductory statistics textbooks, but we have tried to assemble and structure them in a succinct and reader-friendly manner in a stand-alone chapter. This text has long been used in real classroom settings for both undergraduate and graduate students who do or do not major in statistical sciences. We hope that from this chapter, readers would understand the key statistical concepts and terminologies, how to design a study (experimental or observational), how to analyze the data (e.g., describe the data and/or estimate the parameter(s) and make inference), and how to interpret the results. This text would be most useful if it is used as a supplemental material, while the readers take their own statistical courses or it would serve as a great reference text associated with a manual for any statistical software as a self-teaching guide.

A study of statistics anxiety levels of graduate dental hygiene students.

Science.gov (United States)

Welch, Paul S; Jacks, Mary E; Smiley, Lynn A; Walden, Carolyn E; Clark, William D; Nguyen, Carol A

2015-02-01

In light of increased emphasis on evidence-based practice in the profession of dental hygiene, it is important that today's dental hygienist comprehend statistical measures to fully understand research articles, and thereby apply scientific evidence to practice. Therefore, the purpose of this study was to investigate statistics anxiety among graduate dental hygiene students in the U.S. A web-based self-report, anonymous survey was emailed to directors of 17 MSDH programs in the U.S. with a request to distribute to graduate students. The survey collected data on statistics anxiety, sociodemographic characteristics and evidence-based practice. Statistic anxiety was assessed using the Statistical Anxiety Rating Scale. Study significance level was α=0.05. Only 8 of the 17 invited programs participated in the study. Statistical Anxiety Rating Scale data revealed graduate dental hygiene students experience low to moderate levels of statistics anxiety. Specifically, the level of anxiety on the Interpretation Anxiety factor indicated this population could struggle with making sense of scientific research. A decisive majority (92%) of students indicated statistics is essential for evidence-based practice and should be a required course for all dental hygienists. This study served to identify statistics anxiety in a previously unexplored population. The findings should be useful in both theory building and in practical applications. Furthermore, the results can be used to direct future research. Copyright © 2015 The American Dental Hygienists’ Association.

East African Journal of Statistics: Editorial Policies

African Journals Online (AJOL)

Focus and Scope. EAJOSTA publishes the latest finding in applied and theoretical statistics. The journal also accepts papers in operations research, financial mathematics and acturial sciences, all considered as part of applied statistics. Articles must deal with original research, which have not been accepted for publication ...

Detection by voxel-wise statistical analysis of significant changes in regional cerebral glucose uptake in an APP/PS1 transgenic mouse model of Alzheimer's disease.

Science.gov (United States)

Dubois, Albertine; Hérard, Anne-Sophie; Delatour, Benoît; Hantraye, Philippe; Bonvento, Gilles; Dhenain, Marc; Delzescaux, Thierry

2010-06-01

Biomarkers and technologies similar to those used in humans are essential for the follow-up of Alzheimer's disease (AD) animal models, particularly for the clarification of mechanisms and the screening and validation of new candidate treatments. In humans, changes in brain metabolism can be detected by 1-deoxy-2-[(18)F] fluoro-D-glucose PET (FDG-PET) and assessed in a user-independent manner with dedicated software, such as Statistical Parametric Mapping (SPM). FDG-PET can be carried out in small animals, but its resolution is low as compared to the size of rodent brain structures. In mouse models of AD, changes in cerebral glucose utilization are usually detected by [(14)C]-2-deoxyglucose (2DG) autoradiography, but this requires prior manual outlining of regions of interest (ROI) on selected sections. Here, we evaluate the feasibility of applying the SPM method to 3D autoradiographic data sets mapping brain metabolic activity in a transgenic mouse model of AD. We report the preliminary results obtained with 4 APP/PS1 (64+/-1 weeks) and 3 PS1 (65+/-2 weeks) mice. We also describe new procedures for the acquisition and use of "blockface" photographs and provide the first demonstration of their value for the 3D reconstruction and spatial normalization of post mortem mouse brain volumes. Despite this limited sample size, our results appear to be meaningful, consistent, and more comprehensive than findings from previously published studies based on conventional ROI-based methods. The establishment of statistical significance at the voxel level, rather than with a user-defined ROI, makes it possible to detect more reliably subtle differences in geometrically complex regions, such as the hippocampus. Our approach is generic and could be easily applied to other biomarkers and extended to other species and applications. Copyright 2010 Elsevier Inc. All rights reserved.

Improvement of Statistical Decisions under Parametric Uncertainty

Science.gov (United States)

Nechval, Nicholas A.; Nechval, Konstantin N.; Purgailis, Maris; Berzins, Gundars; Rozevskis, Uldis

2011-10-01

A large number of problems in production planning and scheduling, location, transportation, finance, and engineering design require that decisions be made in the presence of uncertainty. Decision-making under uncertainty is a central problem in statistical inference, and has been formally studied in virtually all approaches to inference. The aim of the present paper is to show how the invariant embedding technique, the idea of which belongs to the authors, may be employed in the particular case of finding the improved statistical decisions under parametric uncertainty. This technique represents a simple and computationally attractive statistical method based on the constructive use of the invariance principle in mathematical statistics. Unlike the Bayesian approach, an invariant embedding technique is independent of the choice of priors. It allows one to eliminate unknown parameters from the problem and to find the best invariant decision rule, which has smaller risk than any of the well-known decision rules. To illustrate the proposed technique, application examples are given.

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...

Statistics for lawyers

CERN Document Server

Finkelstein, Michael O

2015-01-01

This classic text, first published in 1990, is designed to introduce law students, law teachers, practitioners, and judges to the basic ideas of mathematical probability and statistics as they have been applied in the law. The third edition includes over twenty new sections, including the addition of timely topics, like New York City police stops, exonerations in death-sentence cases, projecting airline costs, and new material on various statistical techniques such as the randomized response survey technique, rare-events meta-analysis, competing risks, and negative binomial regression. The book consists of sections of exposition followed by real-world cases and case studies in which statistical data have played a role. The reader is asked to apply the theory to the facts, to calculate results (a hand calculator is sufficient), and to explore legal issues raised by quantitative findings. The authors' calculations and comments are given in the back of the book. As with previous editions, the cases and case stu...

Cosmology constraints from shear peak statistics in Dark Energy Survey Science Verification data

International Nuclear Information System (INIS)

Kacprzak, T.; Kirk, D.; Friedrich, O.; Amara, A.; Refregier, A.

2016-01-01

Shear peak statistics has gained a lot of attention recently as a practical alternative to the two-point statistics for constraining cosmological parameters. We perform a shear peak statistics analysis of the Dark Energy Survey (DES) Science Verification (SV) data, using weak gravitational lensing measurements from a 139 deg"2 field. We measure the abundance of peaks identified in aperture mass maps, as a function of their signal-to-noise ratio, in the signal-to-noise range 0 4 would require significant corrections, which is why we do not include them in our analysis. We compare our results to the cosmological constraints from the two-point analysis on the SV field and find them to be in good agreement in both the central value and its uncertainty. Lastly, we discuss prospects for future peak statistics analysis with upcoming DES data.

Significance of the inital cytomorphological and immunocytochemical findings and the correlation with the international prognostic index for the survival in patients with non-Hodgkin’s lymphoma

Directory of Open Access Journals (Sweden)

Mihaljević Biljana

2006-01-01

Full Text Available Background/Aim. Fine-needle aspiration biopsy is a quick, economical, and safe initial method in managing a patient with suspected lymphoma. According to a few reports on this preoblem, the aim of this study was to compare histological findings to cytomorphological ones in needle aspirates. We also compared these findings to the overal survival (OS time. Methods. We analyzed the fine-needle aspiration biopsies of peripheral lymph nodes, and the International Prognostic Index (IPI in 81 patients with non-Hodgkin’s lymphoma (NHL. We put these findings into correlation with OS time. Results. According to the International Working Formulation (IWF criteria, the dominant cell population was as follows: 18 patients had the small cell population, 21 patients had small cleaved cells, 18 patients had the mixed cell population, 21 patients had large cell population, 2 patients had Burkitt lymphoma type, and 1 patient had the dominant lymphoblasts. On presentation, 32 patients had a low IPI index, 32 patients had a low intermediate, and 17 patients had a high intermediate IPI. We confirmed the statistical significance (Kaplan-Mayer of cytomorphology (p = 0.013 and IPI index (p = 0.016 for survival time. During a 48-month follow-up, OS was 37.2 months for the patients with the dominant small cells, and 32 months for the patients with small cleaved cells (PH equivalent to indolent NHL. For the patients with the dominant mixed cell population, large cell population and Burkitt limphoma cell, OS were 17, 14.4, and 9.3 months, respectively (PH equivalent to aggressive NHL. Patients with low IPI had the highest OS, 36 months for the low intermediate and only 11.6 months for the high intermediate IPI index. Conclusion. We concluded that an initial cytological and clinical profile of patients with NHL, might give a quick and relevant information for planning an adequate therapy.

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...

Role of sufficient statistics in stochastic thermodynamics and its implication to sensory adaptation

Science.gov (United States)

Matsumoto, Takumi; Sagawa, Takahiro

2018-04-01

A sufficient statistic is a significant concept in statistics, which means a probability variable that has sufficient information required for an inference task. We investigate the roles of sufficient statistics and related quantities in stochastic thermodynamics. Specifically, we prove that for general continuous-time bipartite networks, the existence of a sufficient statistic implies that an informational quantity called the sensory capacity takes the maximum. Since the maximal sensory capacity imposes a constraint that the energetic efficiency cannot exceed one-half, our result implies that the existence of a sufficient statistic is inevitably accompanied by energetic dissipation. We also show that, in a particular parameter region of linear Langevin systems there exists the optimal noise intensity at which the sensory capacity, the information-thermodynamic efficiency, and the total entropy production are optimized at the same time. We apply our general result to a model of sensory adaptation of E. coli and find that the sensory capacity is nearly maximal with experimentally realistic parameters.

Adhesive capsulitis: contrast-enhansed shoulder MRI findings

International Nuclear Information System (INIS)

Gokalp, Gokhan; Yildirim, Nalan; Yazici, Zeynep; Algin, Oktay

2011-01-01

Full text: Evaluation of contrast-enhanced magnetic resonance imaging (CE-MRI) findings in cases clinically diagnosed as adhesive capsulitis (AC). CE-MRI images of 12 cases diagnosed as AC (13 shoulder joints) and nine control cases were retrospectively evaluated. AC diagnosis was establlished based on the history and clinical symptoms. MR signal intensity changes in the axillary pouch, rotator interval, biceps anchor and anterior posterior capsules were analysed with regard to the presence of abnormal soft tissue and contrast enhancement. Capsular and synovial thickening were measured in the axillary recess and rotator interval on coronal oblique CE T1-weighted images. Patient and control groups were compared by Fisher's exact and McNemar tests in terms of signal intensity changes and contrast enhancement in the described areas. Results: Comparison of the group with AC and the control group regarding intensity changes showed a statistically significant difference in the axillary pouch (P 0.05). Comparison of AC and control groups in terms of contrast enhancement revealed statistically significant differences in the axillary pouch, rotator interval, biceps anchor and anterior-posterior capsules (P < 0.001). A significant difference was determined between the AC and control groups with regard to thickening in axillary pouch and rotator interval (P < 0.001). CE studies are useful for diagnosis of AC as it demonstrates thickening of specific soft-tissue areas like joint capsule and synovium.

Comparison of pre-operative dGEMRIC imaging with intra-operative findings in femoroacetabular impingement: preliminary findings

International Nuclear Information System (INIS)

Bittersohl, Bernd; Apprich, Sebastian; Siebenrock, Klaus A.; Mamisch, Tallal Charles; Hosalkar, Harish S.; Werlen, Stefan A.

2011-01-01

To study standard MRI and dGEMRIC in patients with symptomatic FAI undergoing surgical intervention and compare them with intra-operative findings to see if they were corroborative. Sixteen patients with symptomatic FAI that warranted surgical intervention were prospectively studied. All patients underwent plain radiographic series for FAI assessment followed by standard MRI and dGEMRIC. Subsequently, patients were surgically treated with safe dislocation and the joint was evaluated for any macroscopic signs of damaged cartilage. Data were statistically analyzed. A total of 224 zones in 16 patients were evaluated. One hundred and sixteen zones were intra-operatively rated as normal with mean T1 values of 510.1 ms ± 141.2 ms. Eighty zones had evidence of damage with mean T1 values of 453.1 ms ± 113.6 ms. The difference in these T1 values was significant (p = 0.003). Correlation between standard MRI and intra-operative findings was moderate (r = 0.535, p < 0.001). Intra-operative findings revealed more damage than standard MRI. On standard MRI, 68.6% zones were graded normal while 31.4% had evidence of damage. On intra-operative visualization, 56.4% zones were graded normal and 43.6% had evidence of damage. Correlation between dGEMRIC and intra-operative findings turned out to be weak (r = 0.114, p < 0.126). On T1 assessment 31.4% of zones were graded as normal and 68.6% as damaged. dGEMRIC was significantly different between normal and affected cartilage based on intra-operative assessment. The correlation for morphological findings was limited, underestimating defects. By combining morphological with biochemical assessment dGEMRIC may play some role in the future to prognosticate outcomes and facilitate surgical planning and intervention. (orig.)

Statistical tests to compare motif count exceptionalities

Directory of Open Access Journals (Sweden)

Vandewalle Vincent

2007-03-01

Full Text Available Abstract Background Finding over- or under-represented motifs in biological sequences is now a common task in genomics. Thanks to p-value calculation for motif counts, exceptional motifs are identified and represent candidate functional motifs. The present work addresses the related question of comparing the exceptionality of one motif in two different sequences. Just comparing the motif count p-values in each sequence is indeed not sufficient to decide if this motif is significantly more exceptional in one sequence compared to the other one. A statistical test is required. Results We develop and analyze two statistical tests, an exact binomial one and an asymptotic likelihood ratio test, to decide whether the exceptionality of a given motif is equivalent or significantly different in two sequences of interest. For that purpose, motif occurrences are modeled by Poisson processes, with a special care for overlapping motifs. Both tests can take the sequence compositions into account. As an illustration, we compare the octamer exceptionalities in the Escherichia coli K-12 backbone versus variable strain-specific loops. Conclusion The exact binomial test is particularly adapted for small counts. For large counts, we advise to use the likelihood ratio test which is asymptotic but strongly correlated with the exact binomial test and very simple to use.

Brain herniations into the dural venous sinus or calvarium: MRI findings, possible causes and clinical significance

Energy Technology Data Exchange (ETDEWEB)

Battal, Bilal; Hamcan, Salih; Akgun, Veysel; Sari, Sebahattin; Tasar, Mustafa [Gulhane Military Medical School, Department of Radiology, Ankara (Turkey); Oz, Oguzhan [Gulhane Military Medical School, Department of Neurology, Ankara (Turkey); Castillo, Mauricio [University of North Carolina School of Medicine, Division of Neuroradiology, Department of Radiology, Chapel Hill, NC (United States)

2016-06-15

To determine frequency, imaging features and clinical significance of herniations of brain parenchyma into dural venous sinuses (DVS) and/or calvarium found on MRI. A total of 6160 brain MRI examinations containing at least one high-resolution T1- or T2-weighted sequence were retrospectively evaluated to determine the presence of incidental brain herniations into the DVS or calvarium. MRI sequences available for review were evaluated according to their capability to demonstrate these herniations. Patients' symptoms and clinical findings were recorded. Twenty-one (0.32 %) brain parenchyma herniations into the DVS (n = 18) or calvarium (n = 3) in 20 patients were detected. The most common locations of the herniations were the transverse sinuses (n = 13) and those involving inferior gyrus of the temporal lobe (n = 9). High-resolution T1- and T2-weighted sequences were equally useful in the detection of these brain herniations. According to clinical symptoms, brain herniations were considered to be incidental but headaches were present in nine patients. Brain herniations with surrounding cerebrospinal fluid (CSF) into the DVS and/or calvarium are incidental findings and not proven to be associated with any symptoms. Although rare, these herniations are more common than previously recognized and should not be confused with arachnoid granulations, clots or tumours. (orig.)

Timescales for detecting a significant acceleration in sea level rise.

Science.gov (United States)

Haigh, Ivan D; Wahl, Thomas; Rohling, Eelco J; Price, René M; Pattiaratchi, Charitha B; Calafat, Francisco M; Dangendorf, Sönke

2014-04-14

There is observational evidence that global sea level is rising and there is concern that the rate of rise will increase, significantly threatening coastal communities. However, considerable debate remains as to whether the rate of sea level rise is currently increasing and, if so, by how much. Here we provide new insights into sea level accelerations by applying the main methods that have been used previously to search for accelerations in historical data, to identify the timings (with uncertainties) at which accelerations might first be recognized in a statistically significant manner (if not apparent already) in sea level records that we have artificially extended to 2100. We find that the most important approach to earliest possible detection of a significant sea level acceleration lies in improved understanding (and subsequent removal) of interannual to multidecadal variability in sea level records.

Statistics: The stethoscope of a thinking urologist

Directory of Open Access Journals (Sweden)

Arun S Sivanandam

2009-01-01

Full Text Available Understanding statistical terminology and the ability to appraise clinical research findings and statistical tests are critical to the practice of evidence-based medicine. Urologists require statistics in their toolbox of skills in order to successfully sift through increasingly complex studies and realize the drawbacks of statistical tests. Currently, the level of evidence in urology literature is low and the majority of research abstracts published for the American Urological Association (AUA meetings lag behind for full-text publication because of a lack of statistical reporting. Underlying these issues is a distinct deficiency in solid comprehension of statistics in the literature and a discomfort with the application of statistics for clinical decision-making. This review examines the plight of statistics in urology and investigates the reason behind the white-coat aversion to biostatistics. Resources such as evidence-based medicine websites, primers in statistics, and guidelines for statistical reporting exist for quick reference by urologists. Ultimately, educators should take charge of monitoring statistical knowledge among trainees by bolstering competency requirements and creating sustained opportunities for statistics and methodology exposure.

REANALYSIS OF F-STATISTIC GRAVITATIONAL-WAVE SEARCHES WITH THE HIGHER CRITICISM STATISTIC

International Nuclear Information System (INIS)

Bennett, M. F.; Melatos, A.; Delaigle, A.; Hall, P.

2013-01-01

We propose a new method of gravitational-wave detection using a modified form of higher criticism, a statistical technique introduced by Donoho and Jin. Higher criticism is designed to detect a group of sparse, weak sources, none of which are strong enough to be reliably estimated or detected individually. We apply higher criticism as a second-pass method to synthetic F-statistic and C-statistic data for a monochromatic periodic source in a binary system and quantify the improvement relative to the first-pass methods. We find that higher criticism on C-statistic data is more sensitive by ∼6% than the C-statistic alone under optimal conditions (i.e., binary orbit known exactly) and the relative advantage increases as the error in the orbital parameters increases. Higher criticism is robust even when the source is not monochromatic (e.g., phase-wandering in an accreting system). Applying higher criticism to a phase-wandering source over multiple time intervals gives a ∼> 30% increase in detectability with few assumptions about the frequency evolution. By contrast, in all-sky searches for unknown periodic sources, which are dominated by the brightest source, second-pass higher criticism does not provide any benefits over a first-pass search.

Statistical thinking: tool for development of nursing as a science

Directory of Open Access Journals (Sweden)

Sonia Patricia Carreño Moreno

2017-09-01

Full Text Available Objective: To integrate findings of scientific literature that report on the importance of statistical thinking for development of nursing as a science.  Content synthesis: Literature review of articles published in indexed scientific journals between 1998 and 2017 in databases lilacs, sage Journals, Wiley Online Library, Scopus, bireme, Scielo, ScienceDirect, PubMed, cuiden® y ProQuest. 22 publications were included and findings were extracted, classified, and simplified using descriptor codes, nominal codes, and emerging topics. The following six topics emerged from searches: Education for statistical thinking; Statistical thinking for decision-making in practice; Obstacles to the statistical thinking development; Skills necessary to statistical thinking; Statistics in creating scientific knowledge; and Challenges for statistical thinking development. Conclusion: In the current development of nursing as a science, statistical thinking has primarily been a useful tool for the research field and training of researchers. The existence of obstacles to the statistical thinking development in nurse practitioners has been reported, revealing the need to bound statistics with nursing practice. For this purpose, it is essential to prepare texts and subject of statistics applied to the context of discipline and practice. Descriptors: Biostatistics; Statistics as Topic; Statistics; Science; Nursing(source: decs, bireme.

Applied statistics in ecology: common pitfalls and simple solutions

Science.gov (United States)

E. Ashley Steel; Maureen C. Kennedy; Patrick G. Cunningham; John S. Stanovick

2013-01-01

The most common statistical pitfalls in ecological research are those associated with data exploration, the logic of sampling and design, and the interpretation of statistical results. Although one can find published errors in calculations, the majority of statistical pitfalls result from incorrect logic or interpretation despite correct numerical calculations. There...

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.

[Phalloplethysmographic findings in homosexual pedophile offenders].

Science.gov (United States)

Tichý, P

1991-03-29

Using phalloplethysmographic tests comprising 20 coloured slides of four categories the authors examined 50 homosexual pedophil delinquents and a matched group of heterosexual men. The findings of the two compared groups differed significantly on exposure to three categories of erotic stimuli--adult heterosexual and homosexual objects and child homosexual objects. Only on projection of child heterosexual objects there were no statistically significant differences in the number and magnitude of positive vasomotor reactions recorded in the two groups. Men in the control group responded more frequently and more positively to adult heterosexual objects than homosexual pedophil delinquents. The latter responded more frequently positively to adult and child homosexual objects. In more than one quarter of the delinquents (13 men) a preference of child objects was found, i.e. a deviant pedophil orientation. In seven men the preference of child objects was without sexual differentiation, six men preferred homosexual child objects.

Statistical hypothesis testing with SAS and R

CERN Document Server

Taeger, Dirk

2014-01-01

A comprehensive guide to statistical hypothesis testing with examples in SAS and R When analyzing datasets the following questions often arise:Is there a short hand procedure for a statistical test available in SAS or R?If so, how do I use it?If not, how do I program the test myself? This book answers these questions and provides an overview of the most commonstatistical test problems in a comprehensive way, making it easy to find and performan appropriate statistical test. A general summary of statistical test theory is presented, along with a basicdescription for each test, including the

Determining the significance of associations between two series of discrete events : bootstrap methods /

Energy Technology Data Exchange (ETDEWEB)

Niehof, Jonathan T.; Morley, Steven K.

2012-01-01

We review and develop techniques to determine associations between series of discrete events. The bootstrap, a nonparametric statistical method, allows the determination of the significance of associations with minimal assumptions about the underlying processes. We find the key requirement for this method: one of the series must be widely spaced in time to guarantee the theoretical applicability of the bootstrap. If this condition is met, the calculated significance passes a reasonableness test. We conclude with some potential future extensions and caveats on the applicability of these methods. The techniques presented have been implemented in a Python-based software toolkit.

Clinical, Radiologic, and Legal Significance of "Extensor Response" in Posttraumatic Coma.

Science.gov (United States)

Firsching, Raimund; Woischneck, Dieter; Langejürgen, Alexander; Parreidt, Andreas; Bondar, Imre; Skalej, Martin; Röhl, Friedrich; Voellger, Benjamin

2015-11-01

The timely detection of neurologic deterioration can be critical for the survival of a neurosurgical patient following head injury. Because little reliable evidence is available on the prognostic value of the clinical sign "extensor response" in comatose posttraumatic patients, we investigated the correlation of this clinical sign with outcome and with early radiologic findings from magnetic resonance imaging (MRI). This retrospective analysis of prospectively obtained data included 157 patients who had remained in a coma for a minimum of 24 hours after traumatic brain injury. All patients received a 1.5-T MRI within 10 days (median: 2 days) of the injury. The correlations between clinical findings 12 and 24 hours after the injury-in particular, extensor response and pupillary function, MRI findings, and outcome after 1 year-were investigated. Statistical analysis included contingency tables, Fisher exact test, odds ratios (ORs) with confidence intervals (CIs), and weighted κ values. There were 48 patients with extensor response within the first 24 hours after the injury. Patients with extensor response (World Federation of Neurosurgical Societies coma grade III) statistically were significantly more likely to harbor MRI lesions in the brainstem when compared with patients in a coma who had no further deficiencies (coma grade I; p = 0.0004 by Fisher exact test, OR 10.8 with 95% CI, 2.7-42.5) and patients with unilateral loss of pupil function (coma grade II; p = 0.0187, OR 2.8 with 95% CI, 1.2-6.5). The correlation of brainstem lesions as found by MRI and outcome according to the Glasgow Outcome Scale after 1 year was also highly significant (p ≤ 0.016). The correlation of extensor response and loss of pupil function with an unfavorable outcome and with brainstem lesions revealed by MRI is highly significant. Their sudden onset may be associated with the sudden onset of brainstem dysfunction and should therefore be regarded as one of the most

Study of breast implant rupture: MRI versus surgical findings.

Science.gov (United States)

Vestito, A; Mangieri, F F; Ancona, A; Minervini, C; Perchinunno, V; Rinaldi, S

2012-09-01

This study evaluated the role of breast magnetic resonance (MR) imaging in the selective study breast implant integrity. We retrospectively analysed the signs of breast implant rupture observed at breast MR examinations of 157 implants and determined the sensitivity and specificity of the technique in diagnosing implant rupture by comparing MR data with findings at surgical explantation. The linguine and the salad-oil signs were statistically the most significant signs for diagnosing intracapsular rupture; the presence of siliconomas/seromas outside the capsule and/or in the axillary lymph nodes calls for immediate explantation. In agreement with previous reports, we found a close correlation between imaging signs and findings at explantation. Breast MR imaging can be considered the gold standard in the study of breast implants.

Assessing the Probability that a Finding Is Genuine for Large-Scale Genetic Association Studies.

Science.gov (United States)

Kuo, Chia-Ling; Vsevolozhskaya, Olga A; Zaykin, Dmitri V

2015-01-01

Genetic association studies routinely involve massive numbers of statistical tests accompanied by P-values. Whole genome sequencing technologies increased the potential number of tested variants to tens of millions. The more tests are performed, the smaller P-value is required to be deemed significant. However, a small P-value is not equivalent to small chances of a spurious finding and significance thresholds may fail to serve as efficient filters against false results. While the Bayesian approach can provide a direct assessment of the probability that a finding is spurious, its adoption in association studies has been slow, due in part to the ubiquity of P-values and the automated way they are, as a rule, produced by software packages. Attempts to design simple ways to convert an association P-value into the probability that a finding is spurious have been met with difficulties. The False Positive Report Probability (FPRP) method has gained increasing popularity. However, FPRP is not designed to estimate the probability for a particular finding, because it is defined for an entire region of hypothetical findings with P-values at least as small as the one observed for that finding. Here we propose a method that lets researchers extract probability that a finding is spurious directly from a P-value. Considering the counterpart of that probability, we term this method POFIG: the Probability that a Finding is Genuine. Our approach shares FPRP's simplicity, but gives a valid probability that a finding is spurious given a P-value. In addition to straightforward interpretation, POFIG has desirable statistical properties. The POFIG average across a set of tentative associations provides an estimated proportion of false discoveries in that set. POFIGs are easily combined across studies and are immune to multiple testing and selection bias. We illustrate an application of POFIG method via analysis of GWAS associations with Crohn's disease.

Papillary thyroid carcinoma: comparison between CT features and pathologic findings

International Nuclear Information System (INIS)

Tan Hongna; Gu Yajia; Peng Weijun; Yang Wentao; Huang Dan

2009-01-01

Objective: To evaluate the relationship between the CT imaging features and pathologic findings of papillary thyroid carcinoma (PTC) and papillary thyroid microcarcinoma (PTMC), as well as the CT appearances of Non-papillary thyroid carcinoma(N-PTC). Methods: CT features of 229 PTC, 42 PTMC and 36 N-PTC patients with 264, 57 and 41 lesions respectively were analyzed retrospectively, and comparison was made with the pathologic findings. All data were analyzed by X 2 test. Results: (1) Of PTC lesions, 25.4% (67/264)of the lesions and 2.9% (24/828) of metastatic lymph nodes showed cystic changes. Cyst formation with intracystic high density papillary-like nodules were found in 31.3% (21/67)of the PTC lesions and 37.5% (9/24) of metastatic lymph nodes. The histologic appearances of these tumors demonstrated fibrous tissue forming the wall of cyst, and papillary-like tumor tissue. (2) 75.2% (112/149) of PTC and 33.3% (5/15) of PTMC showed multiple small granular and fine calcifications, and there was statiscally significant difference between the two (P 0.05). However, the degree of enhancement in PTC lesions were less than that of N-PTC, 36.6% (94/257) of PTC and 54.1% (20/37)of N-PTC lesions showed significant enhancement, and there was statistically significant difference (P<0.05). 75.1% of PTC (172/229) and 52.8% of (19/36)N-PTC had cervical lymph node metastases, with a propensity fbr PTC to have more VI region metastatic lymph nodes, 80.8% (139/172)vs 57.9% (11/19), which was statistically significant (both P<0.05). (4)Distant metastases to bone or lung were rare, but N-PTC (5/36) were more likely to produce distant metastases than PTC (5/229), and there was statistically significant difference (P<0.01). Conclusion Multiple, small granular and fine calcifications were found more frequently in PTC than PTMC. Compared with N-PTC, the papillary-like mural nodules of PTC showed less enhancement on post-contrast CT and cervical lymph node metastases were more

Effect of Internet-Based Cognitive Apprenticeship Model (i-CAM) on Statistics Learning among Postgraduate Students.

Science.gov (United States)

Saadati, Farzaneh; Ahmad Tarmizi, Rohani; Mohd Ayub, Ahmad Fauzi; Abu Bakar, Kamariah

2015-01-01

Because students' ability to use statistics, which is mathematical in nature, is one of the concerns of educators, embedding within an e-learning system the pedagogical characteristics of learning is 'value added' because it facilitates the conventional method of learning mathematics. Many researchers emphasize the effectiveness of cognitive apprenticeship in learning and problem solving in the workplace. In a cognitive apprenticeship learning model, skills are learned within a community of practitioners through observation of modelling and then practice plus coaching. This study utilized an internet-based Cognitive Apprenticeship Model (i-CAM) in three phases and evaluated its effectiveness for improving statistics problem-solving performance among postgraduate students. The results showed that, when compared to the conventional mathematics learning model, the i-CAM could significantly promote students' problem-solving performance at the end of each phase. In addition, the combination of the differences in students' test scores were considered to be statistically significant after controlling for the pre-test scores. The findings conveyed in this paper confirmed the considerable value of i-CAM in the improvement of statistics learning for non-specialized postgraduate students.

The statistical analysis of anisotropies

International Nuclear Information System (INIS)

Webster, A.

1977-01-01

One of the many uses to which a radio survey may be put is an analysis of the distribution of the radio sources on the celestial sphere to find out whether they are bunched into clusters or lie in preferred regions of space. There are many methods of testing for clustering in point processes and since they are not all equally good this contribution is presented as a brief guide to what seems to be the best of them. The radio sources certainly do not show very strong clusering and may well be entirely unclustered so if a statistical method is to be useful it must be both powerful and flexible. A statistic is powerful in this context if it can efficiently distinguish a weakly clustered distribution of sources from an unclustered one, and it is flexible if it can be applied in a way which avoids mistaking defects in the survey for true peculiarities in the distribution of sources. The paper divides clustering statistics into two classes: number density statistics and log N/log S statistics. (Auth.)

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:...

The Effects of Flare Definitions on the Statistics of Derived Flare Distrubtions

Science.gov (United States)

Ryan, Daniel; Dominique, Marie; Seaton, Daniel B.; Stegen, Koen; White, Arthur

2016-05-01

The statistical examination of solar flares is crucial to revealing their global characteristics and behaviour. However, statistical flare studies are often performed using standard but basic flare detection algorithms relying on arbitrary thresholds which may affect the derived flare distributions. We explore the effect of the arbitrary thresholds used in the GOES event list and LYRA Flare Finder algorithms. We find that there is a small but significant relationship between the power law exponent of the GOES flare peak flux frequency distribution and the algorithms’ flare start thresholds. We also find that the power law exponents of these distributions are not stable but appear to steepen with increasing peak flux. This implies that the observed flare size distribution may not be a power law at all. We show that depending on the true value of the exponent of the flare size distribution, this deviation from a power law may be due to flares missed by the flare detection algorithms. However, it is not possible determine the true exponent from GOES/XRS observations. Additionally we find that the PROBA2/LYRA flare size distributions are clearly non-power law. We show that this is consistent with an insufficient degradation correction which causes LYRA absolute irradiance values to be unreliable. This means that they should not be used for flare statistics or energetics unless degradation is adequately accounted for. However they can be used to study time variations over shorter timescales and for space weather monitoring.

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.

Characterizing Financial and Statistical Literacy

DEFF Research Database (Denmark)

Di Girolamo, Amalia; Harrison, Glenn W.; Lau, Morten

We characterize the literacy of an individual in a domain by their elicited subjective belief distribution over the possible responses to a question posed in that domain. We consider literacy across several financial, economic and statistical domains. We find considerable demographic heterogeneity...

Statistical field theory of futures commodity prices

Science.gov (United States)

Baaquie, Belal E.; Yu, Miao

2018-02-01

The statistical theory of commodity prices has been formulated by Baaquie (2013). Further empirical studies of single (Baaquie et al., 2015) and multiple commodity prices (Baaquie et al., 2016) have provided strong evidence in support the primary assumptions of the statistical formulation. In this paper, the model for spot prices (Baaquie, 2013) is extended to model futures commodity prices using a statistical field theory of futures commodity prices. The futures prices are modeled as a two dimensional statistical field and a nonlinear Lagrangian is postulated. Empirical studies provide clear evidence in support of the model, with many nontrivial features of the model finding unexpected support from market data.

Fractional statistics of the vortex in two-dimensional superfluids

International Nuclear Information System (INIS)

Chiao, R.Y.; Hansen, A.; Moulthrop, A.A.

1985-01-01

The quantum behavior of two identical point vortices (e.g., in a superfluid 4 He thin film) is studied. It is argued that this system obeys neither Bose nor Fermi statistics, but intermediate or theta statistics: We find that a single vortex in this system possesses quarter-fractional statistics (i.e., theta = π/2 or 3π/2). The source of the theta statistics is identified in the relative zero-point motion of the vortices

Statistics from dynamics in curved spacetime

International Nuclear Information System (INIS)

Parker, L.; Wang, Y.

1989-01-01

We consider quantum fields of spin 0, 1/2, 1, 3/2, and 2 with a nonzero mass in curved spacetime. We show that the dynamical Bogolubov transformations associated with gravitationally induced particle creation imply the connection between spin and statistics: By embedding two flat regions in a curved spacetime, we find that only when one imposes Bose-Einstein statistics for an integer-spin field and Fermi-Dirac statistics for a half-integer-spin field in the first flat region is the same type of statistics propagated from the first to the second flat region. This derivation of the flat-spacetime spin-statistics theorem makes use of curved-spacetime dynamics and does not reduce to any proof given in flat spacetime. We also show in the same manner that parastatistics, up to the fourth order, are consistent with the dynamical evolution of curved spacetime

Improving statistical reasoning theoretical models and practical implications

CERN Document Server

Sedlmeier, Peter

1999-01-01

This book focuses on how statistical reasoning works and on training programs that can exploit people''s natural cognitive capabilities to improve their statistical reasoning. Training programs that take into account findings from evolutionary psychology and instructional theory are shown to have substantially larger effects that are more stable over time than previous training regimens. The theoretical implications are traced in a neural network model of human performance on statistical reasoning problems. This book apppeals to judgment and decision making researchers and other cognitive scientists, as well as to teachers of statistics and probabilistic reasoning.

Juvenile Court Statistics, 1974.

Science.gov (United States)

Corbett, Jacqueline; Vereb, Thomas S.

This report presents information on juvenile court processing of youth in the U.S. during 1974. It is based on data gathered under the National Juvenile Court Statistical Reporting System. Findings can be summarized as follows: (1) 1,252,700 juvenile delinquency cases, excluding traffic offenses, were handled by courts in the U.S. in 1974; (2) the…

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...

The Heuristic Value of p in Inductive Statistical Inference

Directory of Open Access Journals (Sweden)

Joachim I. Krueger

2017-06-01

Full Text Available Many statistical methods yield the probability of the observed data – or data more extreme – under the assumption that a particular hypothesis is true. This probability is commonly known as ‘the’ p-value. (Null Hypothesis Significance Testing ([NH]ST is the most prominent of these methods. The p-value has been subjected to much speculation, analysis, and criticism. We explore how well the p-value predicts what researchers presumably seek: the probability of the hypothesis being true given the evidence, and the probability of reproducing significant results. We also explore the effect of sample size on inferential accuracy, bias, and error. In a series of simulation experiments, we find that the p-value performs quite well as a heuristic cue in inductive inference, although there are identifiable limits to its usefulness. We conclude that despite its general usefulness, the p-value cannot bear the full burden of inductive inference; it is but one of several heuristic cues available to the data analyst. Depending on the inferential challenge at hand, investigators may supplement their reports with effect size estimates, Bayes factors, or other suitable statistics, to communicate what they think the data say.

The Heuristic Value of p in Inductive Statistical Inference.

Science.gov (United States)

Krueger, Joachim I; Heck, Patrick R

2017-01-01

Many statistical methods yield the probability of the observed data - or data more extreme - under the assumption that a particular hypothesis is true. This probability is commonly known as 'the' p -value. (Null Hypothesis) Significance Testing ([NH]ST) is the most prominent of these methods. The p -value has been subjected to much speculation, analysis, and criticism. We explore how well the p -value predicts what researchers presumably seek: the probability of the hypothesis being true given the evidence, and the probability of reproducing significant results. We also explore the effect of sample size on inferential accuracy, bias, and error. In a series of simulation experiments, we find that the p -value performs quite well as a heuristic cue in inductive inference, although there are identifiable limits to its usefulness. We conclude that despite its general usefulness, the p -value cannot bear the full burden of inductive inference; it is but one of several heuristic cues available to the data analyst. Depending on the inferential challenge at hand, investigators may supplement their reports with effect size estimates, Bayes factors, or other suitable statistics, to communicate what they think the data say.

Statistics of Low-Mass Companions to Stars: Implications for Their Origin

Science.gov (United States)

Stepinski, T. F.; Black, D. C.

2001-01-01

One of the more significant results from observational astronomy over the past few years has been the detection, primarily via radial velocity studies, of low-mass companions (LMCs) to solar-like stars. The commonly held interpretation of these is that the majority are "extrasolar planets" whereas the rest are brown dwarfs, the distinction made on the basis of apparent discontinuity in the distribution of M sin i for LMCs as revealed by a histogram. We report here results from statistical analysis of M sin i, as well as of the orbital elements data for available LMCs, to rest the assertion that the LMCs population is heterogeneous. The outcome is mixed. Solely on the basis of the distribution of M sin i a heterogeneous model is preferable. Overall, we find that a definitive statement asserting that LMCs population is heterogeneous is, at present, unjustified. In addition we compare statistics of LMCs with a comparable sample of stellar binaries. We find a remarkable statistical similarity between these two populations. This similarity coupled with marked populational dissimilarity between LMCs and acknowledged planets motivates us to suggest a common origin hypothesis for LMCs and stellar binaries as an alternative to the prevailing interpretation. We discuss merits of such a hypothesis and indicate a possible scenario for the formation of LMCs.

Finding of no significant impact proposed corrective action for the Northeast Site at the Pinellas Plant in Largo, Florida

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-06-01

The U.S. Department of Energy (DOE) has prepared an Environmental Assessment (EA) (DOE/EA-0976) of the proposed corrective action for the Northeast Site at the Pinellas Plant in Largo, Florida. The Northeast Site contains contaminated groundwater that would be removed, treated, and discharged to the Pinellas County Sewer System. Based on the analyses in the EA, the DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act of 1969 (NEPA), 42 U.S.C.4321 et.seq. Therefore, the preparation of an environmental impact statement is not required and the DOE is issuing this Finding of No Significant Impact (FONSI).

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,

Capturing 'R&D excellence': indicators, international statistics, and innovative universities.

Science.gov (United States)

Tijssen, Robert J W; Winnink, Jos J

2018-01-01

Excellent research may contribute to successful science-based technological innovation. We define 'R&D excellence' in terms of scientific research that has contributed to the development of influential technologies, where 'excellence' refers to the top segment of a statistical distribution based on internationally comparative performance scores. Our measurements are derived from frequency counts of literature references ('citations') from patents to research publications during the last 15 years. The 'D' part in R&D is represented by the top 10% most highly cited 'excellent' patents worldwide. The 'R' part is captured by research articles in international scholarly journals that are cited by these patented technologies. After analyzing millions of citing patents and cited research publications, we find very large differences between countries worldwide in terms of the volume of domestic science contributing to those patented technologies. Where the USA produces the largest numbers of cited research publications (partly because of database biases), Switzerland and Israel outperform the US after correcting for the size of their national science systems. To tease out possible explanatory factors, which may significantly affect or determine these performance differentials, we first studied high-income nations and advanced economies. Here we find that the size of R&D expenditure correlates with the sheer size of cited publications, as does the degree of university research cooperation with domestic firms. When broadening our comparative framework to 70 countries (including many medium-income nations) while correcting for size of national science systems, the important explanatory factors become the availability of human resources and quality of science systems. Focusing on the latter factor, our in-depth analysis of 716 research-intensive universities worldwide reveals several universities with very high scores on our two R&D excellence indicators. Confirming the above

The significance of age and sex for the absence of immune response to hepatitis B vaccination

Directory of Open Access Journals (Sweden)

Rosić Ilija

2008-01-01

Full Text Available INTRODUCTION Seroepidemiological investigations after the administration of hepatitis B vaccine have shown that even 15% of vaccinated healthy persons do not generate immune response to the vaccines currently in use. OBJECTIVE The aim of the research is to test the immunogenicity of hepatitis B vaccine in different age groups on the adult vaccinated population sample in Serbia. METHOD The tested general population sample consisted of 154 adult subjects. Immunization was done using the recombinant fungal vaccine obtained by genetic engineering (Euvax B vaccine, manufacturer LG, distributor Sanofi Pasteur. All tested subjects in the research received 1 ml of hepatitis B vaccine administered intramuscularly into the deltoid muscle by 0, 1, 6 schedule. RESULTS In the tested sample, 3.13% of persons aged up to 29 years, 6.25% aged 30-35 year and 19.23% of the tested persons aged 40 years and older had no immune response. The relative risk of “no response" findings was twice higher in the group aged 30-39 as compared to the population aged up to 29 years. The detected risk was six times higher for the population of 40 years and older in comparison to the population aged up to 29 years. Also, the relative risk of “no response" findings for the population of 40 years and older was more than three times higher than for the group aged 30-39. Absent immune response in relation to sex was found to be higher in male subjects. CONCLUSION The rates of “no response" finding was the following: 3.13% in the group aged up to 29 years, 6.25% in the group aged 30-39, as well as in the group aged 40 years and older (19.23%. Immune response in relation to age groups was statistically significantly different (p<0.001, while there was a statistically significant correlation (C=0.473; p<0.001 between the age of the subjects and the immune response. In relation to sex, the “no response" finding was found to be increased in the males, but without any statistically

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…

Intraabdominal serous fluid collections after appendectomy: a normal sonographic finding.

Science.gov (United States)

Aveline, B; Guimaraes, R; Bely, N; Salles, J P; Cugnenc, P H; Frija, G

1993-07-01

The significance of sonographic findings 1 week or less after appendectomy is difficult to evaluate without knowing the inconsequential abnormalities that may occur in these patients. Accordingly, we performed postoperative sonography on patients who had a normal course after appendectomy to determine the findings that can be considered normal within 1 week after surgery. Forty-four patients who had an appendectomy for acute appendicitis and who had normal findings at clinical follow-up 5 days and 6 months later were included in the study. In all patients, sonograms were obtained on the fifth postoperative day and interpreted by a radiologist who did not know the surgical findings. Ten fluid collections (23%) were found in the pericecal area, ranging in size from 10 x 10 mm to 40 x 20 mm. The collections were hypoechoic or anechoic, crescent-shaped, and immobile. Fluid collections were more common in cases of suppurative appendixes (6/20, 30%) than in cases of inflamed appendixes (4/19, 21%) and in retrocecal appendixes (3/9, 33%) than in normally located appendixes (7/34, 21%). However, the differences were not statistically significant (p > .05). Inconsequential fluid collections are detected with considerable frequency on postoperative sonograms 5 days after an appendectomy. Consequently, not every fluid collection should be considered an abscess.

TOPSIS with statistical distances: A new approach to MADM

Directory of Open Access Journals (Sweden)

Vijaya Babu Vommi

2017-01-01

Full Text Available Multiple attribute decision making (MADM methods are very useful in choosing the best alternative among the available finite but conflicting alternatives. TOPSIS is one of the MADM methods, which is simple in its methodology and logic. In TOPSIS, Euclidean distances of each alternative from the positive and negative ideal solutions are utilized to find the best alternative. In literature, apart from Euclidean distances, the city block distances have also been tried to find the separations measures. In general, the attribute data are distributed with unequal ranges and also possess moderate to high correlations. Hence, in the present paper, use of statistical distances is proposed in place of Euclidean distances. Procedures to find the best alternatives are developed using statistical and weighted statistical distances respectively. The proposed methods are illustrated with some industrial problems taken from literature. Results show that the proposed methods can be used as new alternatives in MADM for choosing the best solutions.

Applications of statistical physics and information theory to the analysis of DNA sequences

Science.gov (United States)

Grosse, Ivo

2000-10-01

DNA carries the genetic information of most living organisms, and the of genome projects is to uncover that genetic information. One basic task in the analysis of DNA sequences is the recognition of protein coding genes. Powerful computer programs for gene recognition have been developed, but most of them are based on statistical patterns that vary from species to species. In this thesis I address the question if there exist universal statistical patterns that are different in coding and noncoding DNA of all living species, regardless of their phylogenetic origin. In search for such species-independent patterns I study the mutual information function of genomic DNA sequences, and find that it shows persistent period-three oscillations. To understand the biological origin of the observed period-three oscillations, I compare the mutual information function of genomic DNA sequences to the mutual information function of stochastic model sequences. I find that the pseudo-exon model is able to reproduce the mutual information function of genomic DNA sequences. Moreover, I find that a generalization of the pseudo-exon model can connect the existence and the functional form of long-range correlations to the presence and the length distributions of coding and noncoding regions. Based on these theoretical studies I am able to find an information-theoretical quantity, the average mutual information (AMI), whose probability distributions are significantly different in coding and noncoding DNA, while they are almost identical in all studied species. These findings show that there exist universal statistical patterns that are different in coding and noncoding DNA of all studied species, and they suggest that the AMI may be used to identify genes in different living species, irrespective of their taxonomic origin.

Ultrasonographic Findings of Papillary Thyroid Cancer with or without Hashimoto's Thyroiditis

Energy Technology Data Exchange (ETDEWEB)

Park, Jun Young; Lee, Tae Hyun; Park, Dong Hee [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

2010-04-15

This study was designed to compare the ultrasonographic features of papillary thyroid carcinoma with and without Hashimoto's thyroiditis. This retrospective study included 190 patients with papillary thyroid carcinoma which was proven by neck surgery. The difference in the ultrasonographic findings between papillary thyroid carcinoma with Hashimoto's thyroiditis and papillary thyroid carcinoma without Hashimoto's thyroiditis were calculated statistically. Hashimoto's thyroiditis was diagnosed in 61 of 190 patients following neck surgery. The incidence of coexisting papillary thyroid carcinoma with Hashimoto's thyroiditis was significantly higher in women (p=0.0026). In addition, the frequency of macrocalcification in patients with Hashimoto's thyroiditis was also significantly higher (p=0.0009). Conversely,other ultrasonographic findings including the shape, margin, echogenicity and calcifications, for patients with papillary thyroid carcinoma with Hashimoto's thyroiditis and papillary thyroid carcinoma without Hashimoto's thyroiditis, were not statistically significant. We also found that patients with Hashimoto's thyroiditis who showed no calcification on ultrasonography tended not to detect the papillary carcinoma at a higher frequency. On ultrasonography, macrocalcifications occurred more frequently in patients with Hashimoto's thyroiditis than those without Hashimoto's thyroiditis. Malignant thyroid nodules without calcifications in patients with Hashimoto's thyroiditis more often could not be detected. Therefore, it is important carefully examine patients with Hashimoto's thyroiditis

Accuracy of MRI findings in chronic lateral ankle ligament injury: Comparison with surgical findings

Energy Technology Data Exchange (ETDEWEB)

Park, H.-J. [Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Department of Radiology, Kangwon National University, School of Medicine, Chuncheon (Korea, Republic of); Cha, S.-D. [Department of Orthopedic Surgery, Myongji Hospital, Kwandong University, College of Medicine, Koyang (Korea, Republic of); Kim, S.S. [Department of Radiology, Kangwon National University, School of Medicine, Chuncheon (Korea, Republic of); Rho, M.-H., E-mail: parkhiji@kangwon.ac.kr [Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kwag, H.-J. [Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Park, N.-H. [Department of Radiology, Myongji Hospital, Kwandong University, College of Medicine, Koyang (Korea, Republic of); Lee, S.-Y. [Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

2012-04-15

Aim: To evaluate the accuracy of magnetic resonance imaging (MRI) findings in chronic lateral ankle ligament injury in comparison with that of surgical findings. Materials and methods: Forty-eight cases (25 men, 23 women, mean age 36 years) of clinically suspected chronic ankle ligament injury underwent MRI studies and surgery. Sagittal, coronal, and axial, T1-weighted, spin-echo, proton density and T2-weighted, fast spin-echo images with fat saturation were obtained in all patients. MRI examinations were read in consensus by two fellowship-trained academic musculoskeletal radiologists who evaluated the lateral ankle ligaments, including the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) without clinical information. The results of the MRI studies were then compared with the surgical findings. Results: The MRI findings of ATFL injury showed a sensitivity of detection of complete tears of 75% and specificity of 86%. The sensitivity of detection of partial tears was 75% and the specificity was 78%. The sensitivity of detection of sprains was 44% and the specificity was 88%. Regarding the MRI findings of CFL injury, the sensitivity of detection of complete tears was 50% and the specificity was 98%. The sensitivity of detection of partial tear was 83% and the specificity was 93%. The sensitivity of detection of sprains was 100% and the specificity was 90%. Regarding the ATFL, the accuracies of detection were 88, 58, 77, and 85% for no injury, sprain, partial tear, and complete tear, respectively, and for the CFL the accuracies of detection were 90, 90, 92, and 96% for no injury, sprain, partial tear, and complete tear, respectively. Conclusions: The diagnosis of a complete tear of the ATFL on MRI is more sensitive than the diagnosis of a complete tear of the CFL. MRI findings of CFL injury are diagnostically specific but are not sensitive. However, only normal findings and complete tears were statistically significant between ATFL and CFL (p

Accuracy of MRI findings in chronic lateral ankle ligament injury: Comparison with surgical findings

International Nuclear Information System (INIS)

Park, H.-J.; Cha, S.-D.; Kim, S.S.; Rho, M.-H.; Kwag, H.-J.; Park, N.-H.; Lee, S.-Y.

2012-01-01

Aim: To evaluate the accuracy of magnetic resonance imaging (MRI) findings in chronic lateral ankle ligament injury in comparison with that of surgical findings. Materials and methods: Forty-eight cases (25 men, 23 women, mean age 36 years) of clinically suspected chronic ankle ligament injury underwent MRI studies and surgery. Sagittal, coronal, and axial, T1-weighted, spin-echo, proton density and T2-weighted, fast spin-echo images with fat saturation were obtained in all patients. MRI examinations were read in consensus by two fellowship-trained academic musculoskeletal radiologists who evaluated the lateral ankle ligaments, including the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) without clinical information. The results of the MRI studies were then compared with the surgical findings. Results: The MRI findings of ATFL injury showed a sensitivity of detection of complete tears of 75% and specificity of 86%. The sensitivity of detection of partial tears was 75% and the specificity was 78%. The sensitivity of detection of sprains was 44% and the specificity was 88%. Regarding the MRI findings of CFL injury, the sensitivity of detection of complete tears was 50% and the specificity was 98%. The sensitivity of detection of partial tear was 83% and the specificity was 93%. The sensitivity of detection of sprains was 100% and the specificity was 90%. Regarding the ATFL, the accuracies of detection were 88, 58, 77, and 85% for no injury, sprain, partial tear, and complete tear, respectively, and for the CFL the accuracies of detection were 90, 90, 92, and 96% for no injury, sprain, partial tear, and complete tear, respectively. Conclusions: The diagnosis of a complete tear of the ATFL on MRI is more sensitive than the diagnosis of a complete tear of the CFL. MRI findings of CFL injury are diagnostically specific but are not sensitive. However, only normal findings and complete tears were statistically significant between ATFL and CFL (p

Attachment and Aggressive Manifestations in Younger Adulthood - "Preliminary Findings"

Directory of Open Access Journals (Sweden)

Tatiana Lorincová

2014-07-01

Full Text Available The main topic of the contribution was comparison between retrospective attachment (emocional warmth and rejection and aggressive manifestations (physical aggressivness, verbal aggressivness, anger and hostility among younger adulthood. Bowlby's theory of attachment was that once a core attachment style develops in an infant, it will influence and shape the nature of all intimate relations for the individual moving forward throughout the infant's life cycle. Authors Mikulincer and Shaver (2011 explain how these primary attachment experiences would affect future emotional, cognitive and behavioral processes. Secure adolescents, in comparison to insecure ones are perceived as being less aggressive. Research has pointed out that secure parental attachment promotes adaptive psychological functioning. The direct relationship between attachment security and aggressive/delinquent behaviour is in line with prior evidence that secure adolescents rate higher in terms of emotional and social adjustment, enjoy more positive relationships with their family and peers, and are less likely to engage in externalizing problems, such as antisocial and aggressive behaviours. On the other hand, insecure attachment is connected with aggressive and externalizing behaviour. Hypotheses were formulated on the base of theoretical background and our assumption was, that younger adults with emocional warmth attachment will have lower level of aggressive manifestations (physical aggression, verbal aggression, anger and hostility than younger adults with rejectional attachment. We used two standardized questionnaires for data collection, s.E.M.B.U. Questionnaire, which measured retrospective attachment (emocional warmth and rejection and Questionnaire of Aggressivness, which measured aggressive manifestations. We used statistical analysis and we found statistically significant differencies, which are preliminary findings from broader research, between emocional warmth

On the Statistical Dependency of Identity Theft on Demographics

Science.gov (United States)

di Crescenzo, Giovanni

An improved understanding of the identity theft problem is widely agreed to be necessary to succeed in counter-theft efforts in legislative, financial and research institutions. In this paper we report on a statistical study about the existence of relationships between identity theft and area demographics in the US. The identity theft data chosen was the number of citizen complaints to the Federal Trade Commission in a large number of US municipalities. The list of demographics used for any such municipality included: estimated population, median resident age, estimated median household income, percentage of citizens with a high school or higher degree, percentage of unemployed residents, percentage of married residents, percentage of foreign born residents, percentage of residents living in poverty, density of law enforcement employees, crime index, and political orientation according to the 2004 presidential election. Our study findings, based on linear regression techniques, include statistically significant relationships between the number of identity theft complaints and a non-trivial subset of these demographics.

Effect of Internet-Based Cognitive Apprenticeship Model (i-CAM on Statistics Learning among Postgraduate Students.

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Farzaneh Saadati

Full Text Available Because students' ability to use statistics, which is mathematical in nature, is one of the concerns of educators, embedding within an e-learning system the pedagogical characteristics of learning is 'value added' because it facilitates the conventional method of learning mathematics. Many researchers emphasize the effectiveness of cognitive apprenticeship in learning and problem solving in the workplace. In a cognitive apprenticeship learning model, skills are learned within a community of practitioners through observation of modelling and then practice plus coaching. This study utilized an internet-based Cognitive Apprenticeship Model (i-CAM in three phases and evaluated its effectiveness for improving statistics problem-solving performance among postgraduate students. The results showed that, when compared to the conventional mathematics learning model, the i-CAM could significantly promote students' problem-solving performance at the end of each phase. In addition, the combination of the differences in students' test scores were considered to be statistically significant after controlling for the pre-test scores. The findings conveyed in this paper confirmed the considerable value of i-CAM in the improvement of statistics learning for non-specialized postgraduate students.

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.

The use and misuse of statistical methodologies in pharmacology research.

Science.gov (United States)

Marino, Michael J

2014-01-01

Descriptive, exploratory, and inferential statistics are necessary components of hypothesis-driven biomedical research. Despite the ubiquitous need for these tools, the emphasis on statistical methods in pharmacology has become dominated by inferential methods often chosen more by the availability of user-friendly software than by any understanding of the data set or the critical assumptions of the statistical tests. Such frank misuse of statistical methodology and the quest to reach the mystical αstatistical training. Perhaps more critically, a poor understanding of statistical tools limits the conclusions that may be drawn from a study by divorcing the investigator from their own data. The net result is a decrease in quality and confidence in research findings, fueling recent controversies over the reproducibility of high profile findings and effects that appear to diminish over time. The recent development of "omics" approaches leading to the production of massive higher dimensional data sets has amplified these issues making it clear that new approaches are needed to appropriately and effectively mine this type of data. Unfortunately, statistical education in the field has not kept pace. This commentary provides a foundation for an intuitive understanding of statistics that fosters an exploratory approach and an appreciation for the assumptions of various statistical tests that hopefully will increase the correct use of statistics, the application of exploratory data analysis, and the use of statistical study design, with the goal of increasing reproducibility and confidence in the literature. Copyright © 2013. Published by Elsevier Inc.

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

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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.

Information Geometry, Inference Methods and Chaotic Energy Levels Statistics

OpenAIRE

Cafaro, Carlo

2008-01-01

In this Letter, we propose a novel information-geometric characterization of chaotic (integrable) energy level statistics of a quantum antiferromagnetic Ising spin chain in a tilted (transverse) external magnetic field. Finally, we conjecture our results might find some potential physical applications in quantum energy level statistics.

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

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

Kappa statistic to measure agreement beyond chance in free-response assessments.

Science.gov (United States)

Carpentier, Marc; Combescure, Christophe; Merlini, Laura; Perneger, Thomas V

2017-04-19

The usual kappa statistic requires that all observations be enumerated. However, in free-response assessments, only positive (or abnormal) findings are notified, but negative (or normal) findings are not. This situation occurs frequently in imaging or other diagnostic studies. We propose here a kappa statistic that is suitable for free-response assessments. We derived the equivalent of Cohen's kappa statistic for two raters under the assumption that the number of possible findings for any given patient is very large, as well as a formula for sampling variance that is applicable to independent observations (for clustered observations, a bootstrap procedure is proposed). The proposed statistic was applied to a real-life dataset, and compared with the common practice of collapsing observations within a finite number of regions of interest. The free-response kappa is computed from the total numbers of discordant (b and c) and concordant positive (d) observations made in all patients, as 2d/(b + c + 2d). In 84 full-body magnetic resonance imaging procedures in children that were evaluated by 2 independent raters, the free-response kappa statistic was 0.820. Aggregation of results within regions of interest resulted in overestimation of agreement beyond chance. The free-response kappa provides an estimate of agreement beyond chance in situations where only positive findings are reported by raters.

High-resolution CT findings of interstitial pneumonia in patients with dermatomyositis. Comparison between classic and amyopathic forms

International Nuclear Information System (INIS)

Watanabe, Wataru

2007-01-01

The objective of this study was to compare high-resolution CT (HRCT) findings of interstitial pneumonia associated with dermatomyositis (DM) based on disease form, classic (CDM) vs. amyopathic (ADM) form, and clinical presentation, acute or subacute vs. chronic presentation. HRCT findings of 18 patients (CDM 9, ADM 9) were reviewed retrospectively. HRCT was interpreted by two experienced, board-certified radiologists. Difference in the interpretation was settled by consensus. Frequency of the HRCT findings compared between CDM and ADM, and between acute or subacute and chronic presentation. The most frequent finding was bronchovascular bundle irregularity (77%), followed by ground-glass attenuation (72%), subpleural curvilinear shadow (72%) and parenchymal band (72%). Honeycombing was not noted in any case. Linear opacities were significantly more frequent, and bronchiectasis was significantly less frequent in ADM than in CDM (p<0.05). Bronchiectasis was more common in chronic than in acute/subacute presentation, but there was no statistically significant difference. HRCT findings of interstitial pneumonia associated with DM varied between CDM and ADM. Honeycombing was not noted in any case. Linear opacities were significantly more frequent, and bronchiectasis was significantly less frequent in ADM than in CDM. The findings on HRCT were not different between acute or subacute and chronic presentation. (author)

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...

Topology for Statistical Modeling of Petascale Data

Energy Technology Data Exchange (ETDEWEB)

Pascucci, Valerio [Univ. of Utah, Salt Lake City, UT (United States); Levine, Joshua [Univ. of Utah, Salt Lake City, UT (United States); Gyulassy, Attila [Univ. of Utah, Salt Lake City, UT (United States); Bremer, P. -T. [Univ. of Utah, Salt Lake City, UT (United States)

2013-10-31

Many commonly used algorithms for mathematical analysis do not scale well enough to accommodate the size or complexity of petascale data produced by computational simulations. The primary goal of this project is to develop new mathematical tools that address both the petascale size and uncertain nature of current data. At a high level, the approach of the entire team involving all three institutions is based on the complementary techniques of combinatorial topology and statistical modelling. In particular, we use combinatorial topology to filter out spurious data that would otherwise skew statistical modelling techniques, and we employ advanced algorithms from algebraic statistics to efficiently find globally optimal fits to statistical models. The overall technical contributions can be divided loosely into three categories: (1) advances in the field of combinatorial topology, (2) advances in statistical modelling, and (3) new integrated topological and statistical methods. Roughly speaking, the division of labor between our 3 groups (Sandia Labs in Livermore, Texas A&M in College Station, and U Utah in Salt Lake City) is as follows: the Sandia group focuses on statistical methods and their formulation in algebraic terms, and finds the application problems (and data sets) most relevant to this project, the Texas A&M Group develops new algebraic geometry algorithms, in particular with fewnomial theory, and the Utah group develops new algorithms in computational topology via Discrete Morse Theory. However, we hasten to point out that our three groups stay in tight contact via videconference every 2 weeks, so there is much synergy of ideas between the groups. The following of this document is focused on the contributions that had grater direct involvement from the team at the University of Utah in Salt Lake City.

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.

Cluster-level statistical inference in fMRI datasets: The unexpected behavior of random fields in high dimensions.

Science.gov (United States)

Bansal, Ravi; Peterson, Bradley S

2018-06-01

Identifying regional effects of interest in MRI datasets usually entails testing a priori hypotheses across many thousands of brain voxels, requiring control for false positive findings in these multiple hypotheses testing. Recent studies have suggested that parametric statistical methods may have incorrectly modeled functional MRI data, thereby leading to higher false positive rates than their nominal rates. Nonparametric methods for statistical inference when conducting multiple statistical tests, in contrast, are thought to produce false positives at the nominal rate, which has thus led to the suggestion that previously reported studies should reanalyze their fMRI data using nonparametric tools. To understand better why parametric methods may yield excessive false positives, we assessed their performance when applied both to simulated datasets of 1D, 2D, and 3D Gaussian Random Fields (GRFs) and to 710 real-world, resting-state fMRI datasets. We showed that both the simulated 2D and 3D GRFs and the real-world data contain a small percentage (<6%) of very large clusters (on average 60 times larger than the average cluster size), which were not present in 1D GRFs. These unexpectedly large clusters were deemed statistically significant using parametric methods, leading to empirical familywise error rates (FWERs) as high as 65%: the high empirical FWERs were not a consequence of parametric methods failing to model spatial smoothness accurately, but rather of these very large clusters that are inherently present in smooth, high-dimensional random fields. In fact, when discounting these very large clusters, the empirical FWER for parametric methods was 3.24%. Furthermore, even an empirical FWER of 65% would yield on average less than one of those very large clusters in each brain-wide analysis. Nonparametric methods, in contrast, estimated distributions from those large clusters, and therefore, by construct rejected the large clusters as false positives at the nominal

Statistical approaches in published ophthalmic clinical science papers: a comparison to statistical practice two decades ago.

Science.gov (United States)

Zhang, Harrison G; Ying, Gui-Shuang

2018-02-09

The aim of this study is to evaluate the current practice of statistical analysis of eye data in clinical science papers published in British Journal of Ophthalmology ( BJO ) and to determine whether the practice of statistical analysis has improved in the past two decades. All clinical science papers (n=125) published in BJO in January-June 2017 were reviewed for their statistical analysis approaches for analysing primary ocular measure. We compared our findings to the results from a previous paper that reviewed BJO papers in 1995. Of 112 papers eligible for analysis, half of the studies analysed the data at an individual level because of the nature of observation, 16 (14%) studies analysed data from one eye only, 36 (32%) studies analysed data from both eyes at ocular level, one study (1%) analysed the overall summary of ocular finding per individual and three (3%) studies used the paired comparison. Among studies with data available from both eyes, 50 (89%) of 56 papers in 2017 did not analyse data from both eyes or ignored the intereye correlation, as compared with in 60 (90%) of 67 papers in 1995 (P=0.96). Among studies that analysed data from both eyes at an ocular level, 33 (92%) of 36 studies completely ignored the intereye correlation in 2017, as compared with in 16 (89%) of 18 studies in 1995 (P=0.40). A majority of studies did not analyse the data properly when data from both eyes were available. The practice of statistical analysis did not improve in the past two decades. Collaborative efforts should be made in the vision research community to improve the practice of statistical analysis for ocular data. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Why Does Emissions Trading under the EU ETS Not Affect Firms' Competitiveness? Empirical Findings from the Literature

OpenAIRE

Joltreau, Eugénie; Sommerfeld, Katrin

2017-01-01

Environmental policies may have important consequences for firms’ competitiveness or profitability. However, the empirical literature shows that hardly any statistically significant effects on firms can be detected for the European Union Emissions Trading Scheme (EU ETS). On the basis of existing literature, we focus on potential explanations for why the empirical literature finds hardly any significant competitiveness effects on firms, least not during the first two phases of the scheme (...

Manipulating the Alpha Level Cannot Cure Significance Testing

Directory of Open Access Journals (Sweden)

David Trafimow

2018-05-01

Full Text Available We argue that making accept/reject decisions on scientific hypotheses, including a recent call for changing the canonical alpha level from p = 0.05 to p = 0.005, is deleterious for the finding of new discoveries and the progress of science. Given that blanket and variable alpha levels both are problematic, it is sensible to dispense with significance testing altogether. There are alternatives that address study design and sample size much more directly than significance testing does; but none of the statistical tools should be taken as the new magic method giving clear-cut mechanical answers. Inference should not be based on single studies at all, but on cumulative evidence from multiple independent studies. When evaluating the strength of the evidence, we should consider, for example, auxiliary assumptions, the strength of the experimental design, and implications for applications. To boil all this down to a binary decision based on a p-value threshold of 0.05, 0.01, 0.005, or anything else, is not acceptable.

Number projected statistics and the pairing correlations at high excitation energies

International Nuclear Information System (INIS)

Esebbag, C.; Egido, J.L.

1993-01-01

We analyze the use of particle-number projected statistics (PNPS) as an effective way to include the quantum and statistical fluctuations, associated with the pairing degree of freedom, left out in finite-temperature mean-field theories. As a numerical application the exact-soluble degenerate model is worked out. In particular, we find that the sharp temperature-induced superfluid-normal phase transition, predicted in the mean-field approximations, is washed out in the PNPS. Some approximations as well as the Landau prescription to include statistical fluctuations are also discussed. We find that the Landau prescription provides a reasonable approximation to the PNPS. (orig.)

Statistical analysis of bankrupting and non-bankrupting stocks

Science.gov (United States)

Li, Qian; Wang, Fengzhong; Wei, Jianrong; Liang, Yuan; Huang, Jiping; Stanley, H. Eugene

2012-04-01

The recent financial crisis has caused extensive world-wide economic damage, affecting in particular those who invested in companies that eventually filed for bankruptcy. A better understanding of stocks that become bankrupt would be helpful in reducing risk in future investments. Economists have conducted extensive research on this topic, and here we ask whether statistical physics concepts and approaches may offer insights into pre-bankruptcy stock behavior. To this end, we study all 20092 stocks listed in US stock markets for the 20-year period 1989-2008, including 4223 (21 percent) that became bankrupt during that period. We find that, surprisingly, the distributions of the daily returns of those stocks that become bankrupt differ significantly from those that do not. Moreover, these differences are consistent for the entire period studied. We further study the relation between the distribution of returns and the length of time until bankruptcy, and observe that larger differences of the distribution of returns correlate with shorter time periods preceding bankruptcy. This behavior suggests that sharper fluctuations in the stock price occur when the stock is closer to bankruptcy. We also analyze the cross-correlations between the return and the trading volume, and find that stocks approaching bankruptcy tend to have larger return-volume cross-correlations than stocks that are not. Furthermore, the difference increases as bankruptcy approaches. We conclude that before a firm becomes bankrupt its stock exhibits unusual behavior that is statistically quantifiable.

Statistical physics of pairwise probability models

DEFF Research Database (Denmark)

Roudi, Yasser; Aurell, Erik; Hertz, John

2009-01-01

(dansk abstrakt findes ikke) Statistical models for describing the probability distribution over the states of biological systems are commonly used for dimensional reduction. Among these models, pairwise models are very attractive in part because they can be fit using a reasonable amount of  data......: knowledge of the means and correlations between pairs of elements in the system is sufficient. Not surprisingly, then, using pairwise models for studying neural data has been the focus of many studies in recent years. In this paper, we describe how tools from statistical physics can be employed for studying...

MRI findings in soccer players with long-standing adductor-related groin pain and asymptomatic controls

DEFF Research Database (Denmark)

Branci, Sonia; Thorborg, Kristian; Bech, Birthe Højlund

2015-01-01

. Participants underwent identical standardised and reliable clinical examination, and MRI scans (3 T) of the pelvis performed by a blinded observer. Images were consensus rated by three blinded radiologists according to a standardised MRI evaluation protocol. The associations between clinical adductor......-related findings and pathological MRI findings were investigated with χ(2) statistics and OR. RESULTS: Central disc protrusion (p=0.027) and higher grades of pubic bone marrow oedema (BMO; p=0.027) were significantly more present in symptomatic players than asymptomatic players. However, up to 71% of asymptomatic...

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...

Do laryngoscopic findings reflect the characteristics of reflux in patients with laryngopharyngeal reflux?

Science.gov (United States)

Lee, Y C; Kwon, O E; Park, J M; Eun, Y G

2018-02-01

To analyse the association between 24-hour multichannel intraluminal impedance-pH (24-h MII-pH) parameters and each item of the reflux finding score (RFS) to determine whether the laryngoscopic findings of the RFS could reflect the characteristics of reflux in patients with laryngopharyngeal reflux (LPR). Prospective cohort study. Tertiary care referral medical centre. Patients complaining of LPR symptoms were evaluated via a 24-hour MII-pH. Among them, 99 patients whose LPR was confirmed via 24-hour MII-pH were enrolled in this study. Correlations between RFS ratings and 24-hour MII-pH parameters were evaluated and compared between patients with or without each laryngoscopic finding used in the RFS. Subglottic oedema had a statistically significant positive correlation with number of non-acid LPR and non-acid full column reflux events. Ventricular obliteration and posterior commissure hypertrophy showed a significant correlation with non-acid exposure time and total reflux exposure time. We also found a significant correlation between granuloma/granulation score and number of acid LPR events. The numbers of non-acid LPR and full column reflux events in patients with subglottic oedema were significantly higher than those without subglottic oedema. Among the laryngoscopic findings used in the RFS, subglottic oedema is specific for non-acid reflux episodes, and granuloma/granulation is specific for acid reflux episodes. © 2017 John Wiley & Sons Ltd.

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

Directory of Open Access Journals (Sweden)

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

Prognostic value of clinical and Doppler echocardiographic findings in children and adolescents with significant rheumatic valvular disease

International Nuclear Information System (INIS)

Araújo, Fátima Derlene da Rocha; Goulart, Eugênio Marcos Andrade; Meira, Zilda Maria Alves

2012-01-01

The diagnosis of acute rheumatic fever (RF) is based on clinical findings. However, during the chronic phase of the disease, the clinical approach is not sufficient for the follow-up of the patients and the Doppler echocardiography is a tool for the diagnosis of cardiac involvement. Prognostic variables that influence long-term outcomes are not well known. 462 patients with RF according to Jones criteria were studied, and followed-up from the initial attack to 13.6 ± 4.6 years. All patients underwent clinical assessment and Doppler echocardiography for the detection of heart valve involvement in the acute and chronic phases. Multivariate logistic regression analysis was used to identify the factors influencing long-term heart valve disease. Carditis occurred in 55.8% and subclinical valvulitis in 35.3% patients. In the chronic phase, 33% of the patients had significant valvular heart disease. No normal Doppler echocardiography exam was observed on patients who had severe valvulitis, although heart auscultation had become normal in 13% of these. In the multivariate analysis, only the severity of carditis and the mitral and/or aortic valvulitis were associated with significant valvular heart disease. Chorea or arthritis were protective factors for significant valvular heart disease, odds ratio 0.41 (95% C.I. 0.22 – 0.77) and 0.43 (95% C.I. 0.23 – 0.82), respectively. Our study suggests that the use of Doppler echocardiography during RF helps to identify prognostic factors regarding the development of significant valvular heart disease. Initial severe carditis is an important factor in the long-term prognosis of chronic RHD, whereas arthritis and chore during the initial episode of RF appears to be protective. Strict secondary prophylaxis should be mandatory in high risk patients

Sonographic findings and clinical significance of uterine synechiae in pregnancy: Report of 6 cases

International Nuclear Information System (INIS)

Lee, Jung Hyung; Kim, Jung Sik

1994-01-01

We analyzed the sonograms of 6 cases with uterine synechiae in pregnancy. The diagnosis was based on the clinical and sonographic findings. Previous curret age during the artificial abortion and/or after the spontaneous abortion had been done in 5 cases (83.3%). In all cases, uterine synechia in pregnancy was recognized asintra-amniotic sheet containing hypoechoic central zone and an hyperechoic outer layers. Y-shaped splitting of thehyperechoic outer layers was seen against the uterine wall. The placenta extended along the sheet in 4 cases. Uterine synechiae in pregnancy should be distinguished from amniotic band syndrome by the characteristic snographic findings, and unwarranted abortion of normal fetus should be avoided

Analysis of mammographic findings of breast cancer

International Nuclear Information System (INIS)

Park, Hyun Joo; Han, Heon; Yang, Dal Mo; Chung, Hyo Sun; Kim, Jee Eun; Kim, Young Chae

1995-01-01

This study is to describe authors' experience on mammographic findings of breast cancer and to know if there is difference between 35 years of age or younger and older groups. Mammograms of 72 patients with breast cancer detected from January, 1991 to December, 1993 were retrospectively analysed. Mammographic findings were classified into mass only, mass with microcalcifications, microcalcifications only and others. Marginal characteristics of mass were classified into spiculated, poorly marginated and well marginated. Shape of microcalcifications were classified into casting, granular and mixed types. These findings were compared between 35 years of age or younger and older groups. Mammogram showed mass only in 33 patients (46%), mass with microcalcifications in 26 patients (36%), microcalcifications only in seven (10%) and other findings in six (8%). Other findings were architectural distortion, asymmetric high density and incidental breast carcinoma from paraffinoma in one patient respectively, and dense breast in three patients. The margins of the breast mass were spiculated in ten (17%). poorly marginated in 30 (51%), well-marginated in 19 (32%). Shape of microcalcifications were casting type in 13 (40%). granular in 14 (42%) and mixed in six (18%) cases. 3 patients had dense breast with which mammography did not demonstrate the lesion. 3 patients without mammographically demonstrable lesions due to dense breasts were under 35 years in age, and there was statistically significant difference between the two groups (ρ -value < 0.05). Microcalcifications only was more common findings in 35 years of age or younger. The most important mammographic findings of breast cancer were mass and microcalcifications. Architectural distortion and asymmetric high density were additional findings. In 35 years of age or younger, microcalcifications only was an important finding because mass lesions are frequently masked by dense breast. Thus other imaging modalities, such as

Statistical analysis of natural disasters and related losses

CERN Document Server

Pisarenko, VF

2014-01-01

The study of disaster statistics and disaster occurrence is a complicated interdisciplinary field involving the interplay of new theoretical findings from several scientific fields like mathematics, physics, and computer science. Statistical studies on the mode of occurrence of natural disasters largely rely on fundamental findings in the statistics of rare events, which were derived in the 20th century. With regard to natural disasters, it is not so much the fact that the importance of this problem for mankind was recognized during the last third of the 20th century - the myths one encounters in ancient civilizations show that the problem of disasters has always been recognized - rather, it is the fact that mankind now possesses the necessary theoretical and practical tools to effectively study natural disasters, which in turn supports effective, major practical measures to minimize their impact. All the above factors have resulted in considerable progress in natural disaster research. Substantial accrued ma...

Clinical, laboratory, and hemostatic findings in cats with naturally occurring sepsis.

Science.gov (United States)

Klainbart, Sigal; Agi, Limor; Bdolah-Abram, Tali; Kelmer, Efrat; Aroch, Itamar

2017-11-01

OBJECTIVE To characterize clinical and laboratory findings in cats with naturally occurring sepsis, emphasizing hemostasis-related findings, and evaluate these variables for associations with patient outcomes. DESIGN Prospective, observational, clinical study. ANIMALS 31 cats with sepsis and 33 healthy control cats. PROCEDURES Data collected included history; clinical signs; results of hematologic, serum biochemical, and hemostatic tests; diagnosis; and outcome (survival vs death during hospitalization or ≤ 30 days after hospital discharge). Differences between cats with and without sepsis and associations between variables of interest and death were analyzed statistically. RESULTS The sepsis group included cats with pyothorax (n = 10), septic peritonitis (7), panleukopenia virus infection (5), bite wounds (5), abscesses and diffuse cellulitis (3), and pyometra (1). Common clinical abnormalities included dehydration (21 cats), lethargy (21), anorexia (18), pale mucous membranes (15), and dullness (15). Numerous clinicopathologic abnormalities were identified in cats with sepsis; novel findings included metarubricytosis, hypertriglyceridemia, and high circulating muscle enzyme activities. Median activated partial thromboplastin time and plasma D-dimer concentrations were significantly higher, and total protein C and antithrombin activities were significantly lower, in the sepsis group than in healthy control cats. Disseminated intravascular coagulopathy was uncommon (4/22 [18%] cats with sepsis). None of the clinicopathologic abnormalities were significantly associated with death on multivariate analysis. CONCLUSIONS AND CLINICAL RELEVANCE Cats with sepsis had multiple hematologic, biochemical, and hemostatic abnormalities on hospital admission, including several findings suggestive of hemostatic derangement. Additional research including larger numbers of cats is needed to further investigate these findings and explore associations with outcome.

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

Directory of Open Access Journals (Sweden)

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

Understanding Statistics - Cancer Statistics

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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.

Statistical analysis of 4 types of neck whiplash injuries based on classical meridian theory.

Science.gov (United States)

Chen, Yemeng; Zhao, Yan; Xue, Xiaolin; Li, Hui; Wu, Xiuyan; Zhang, Qunce; Zheng, Xin; Wang, Tianfang

2015-01-01

As one component of the Chinese medicine meridian system, the meridian sinew (Jingjin, (see text), tendino-musculo) is specially described as being for acupuncture treatment of the musculoskeletal system because of its dynamic attributes and tender point correlations. In recent decades, the therapeutic importance of the sinew meridian has become revalued in clinical application. Based on this theory, the authors have established therapeutic strategies of acupuncture treatment in Whiplash-Associated Disorders (WAD) by categorizing four types of neck symptom presentations. The advantage of this new system is to make it much easier for the clinician to find effective acupuncture points. This study attempts to prove the significance of the proposed therapeutic strategies by analyzing data collected from a clinical survey of various WAD using non-supervised statistical methods, such as correlation analysis, factor analysis, and cluster analysis. The clinical survey data have successfully verified discrete characteristics of four neck syndromes, based upon the range of motion (ROM) and tender point location findings. A summary of the relationships among the symptoms of the four neck syndromes has shown the correlation coefficient as having a statistical significance (P < 0.01 or P < 0.05), especially with regard to ROM. Furthermore, factor and cluster analyses resulted in a total of 11 categories of general symptoms, which implies syndrome factors are more related to the Liver, as originally described in classical theory. The hypothesis of meridian sinew syndromes in WAD is clearly supported by the statistical analysis of the clinical trials. This new discovery should be beneficial in improving therapeutic outcomes.

Statistical reviewers improve reporting in biomedical articles: a randomized trial.

Directory of Open Access Journals (Sweden)

Erik Cobo

2007-03-01

reviewers had no effect on change in overall quality as measured by the Goodman scale (0.9, 95% CI: -0.3-+2.1. The estimated effect of adding a statistical reviewer was 5.5 (95% CI: 4.3-6.7, showing a significant improvement in quality.This prospective randomized study shows the positive effect of adding a statistical reviewer to the field-expert peers in improving manuscript quality. We did not find a statistically significant positive effect by suggesting reviewers use reporting guidelines.

Brain Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy Findings of Children with Kernicterus

International Nuclear Information System (INIS)

Sarı, Sahabettin; Yavuz, Alpaslan; Batur, Aabdussamet; Bora, Aydın; Caksen, Huseyin

2015-01-01

The term kernicterus, or bilirubin encephalopathy, is used to describe pathological bilirubin staining of the basal ganglia, brain stem, and cerebellum, and is associated with hyperbilirubinemia. Kernicterus generally occurs in untreated hyperbilirubinemia or cases where treatment is delayed. Magnetic resonance imaging (MRI)-based studies have shown characteristic findings in kernicterus. The objective of our study was to describe the role of 1 H magnetic resonance spectroscopy (MRS) in demonstrating these metabolic changes and to review conventional MRI findings of kernicterus. Forty-eight pediatric cases with kernicterus were included in this study. MRI and MRS examinations were performed on variable dates (10–29 days after birth). NAA, Cr, Cho, NAA/Cr, NAA/Cho, and Cho/Cr values were evaluated visually and by computer analysis. There was no statistically significant difference between the NAA and Cho levels in the acute kernicterus patients and the control group (healthy patients), whereas both were significantly elevated in the chronic kernicterus patients. Both the mean NAA/Cr and Cho/Cr ratio values were significantly higher in the acute and chronic cases compared to the control group. The NAA/Cho ratio value was statistically lower in the acute cases than in the control group while it was similar in the chronic cases. Conventional MR imaging and 1 H-MRS are important complementary tools in the diagnostics of neonatal bilirubin encephalopathy. This study provided important information for applying these MR modalities in the evaluation of neonates with bilirubin encephalopathy

Anomalous spin-dependent tunneling statistics in Fe/MgO/Fe junctions induced by disorder at the interface

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Yan, Jiawei; Wang, Shizhuo; Xia, Ke; Ke, Youqi

2018-01-01

We present first-principles analysis of interfacial disorder effects on spin-dependent tunneling statistics in thin Fe/MgO/Fe magnetic tunnel junctions. We find that interfacial disorder scattering can significantly modulate the tunneling statistics in the minority spin of the parallel configuration (PC) while all other spin channels remain dominated by the Poissonian process. For the minority-spin channel of PC, interfacial disorder scattering favors the formation of resonant tunneling channels by lifting the limitation of symmetry conservation at low concentration, presenting an important sub-Poissonian process in PC, but is destructive to the open channels at high concentration. We find that the important modulation of tunneling statistics is independent of the type of interfacial disorder. A bimodal distribution function of transmission with disorder dependence is introduced and fits very well our first-principles results. The increase of MgO thickness can quickly change the tunneling from a sub-Poissonian to Poissonian dominated process in the minority spin of PC with disorder. Our results provide a sensitive detection method of an ultralow concentration of interfacial defects.

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

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

Directory of Open Access Journals (Sweden)

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.

[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.

THE ABSOLUTE MAGNITUDE OF RRc VARIABLES FROM STATISTICAL PARALLAX

International Nuclear Information System (INIS)

Kollmeier, Juna A.; Burns, Christopher R.; Thompson, Ian B.; Preston, George W.; Crane, Jeffrey D.; Madore, Barry F.; Morrell, Nidia; Prieto, José L.; Shectman, Stephen; Simon, Joshua D.; Villanueva, Edward; Szczygieł, Dorota M.; Gould, Andrew; Sneden, Christopher; Dong, Subo

2013-01-01

We present the first definitive measurement of the absolute magnitude of RR Lyrae c-type variable stars (RRc) determined purely from statistical parallax. We use a sample of 242 RRc variables selected from the All Sky Automated Survey for which high-quality light curves, photometry, and proper motions are available. We obtain high-resolution echelle spectra for these objects to determine radial velocities and abundances as part of the Carnegie RR Lyrae Survey. We find that M V,RRc = 0.59 ± 0.10 at a mean metallicity of [Fe/H] = –1.59. This is to be compared with previous estimates for RRab stars (M V,RRab = 0.76 ± 0.12) and the only direct measurement of an RRc absolute magnitude (RZ Cephei, M V,RRc = 0.27 ± 0.17). We find the bulk velocity of the halo relative to the Sun to be (W π , W θ , W z ) = (12.0, –209.9, 3.0) km s –1 in the radial, rotational, and vertical directions with dispersions (σ W π ,σ W θ ,σ W z ) = (150.4, 106.1, 96.0) km s -1 . For the disk, we find (W π , W θ , W z ) = (13.0, –42.0, –27.3) km s –1 relative to the Sun with dispersions (σ W π ,σ W θ ,σ W z ) = (67.7,59.2,54.9) km s -1 . Finally, as a byproduct of our statistical framework, we are able to demonstrate that UCAC2 proper-motion errors are significantly overestimated as verified by UCAC4

Audit sampling: A qualitative study on the role of statistical and non-statistical sampling approaches on audit practices in Sweden

OpenAIRE

Ayam, Rufus Tekoh

2011-01-01

PURPOSE: The two approaches to audit sampling; statistical and nonstatistical have been examined in this study. The overall purpose of the study is to explore the current extent at which statistical and nonstatistical sampling approaches are utilized by independent auditors during auditing practices. Moreover, the study also seeks to achieve two additional purposes; the first is to find out whether auditors utilize different sampling techniques when auditing SME´s (Small and Medium-Sized Ente...

p-Curve and Effect Size: Correcting for Publication Bias Using Only Significant Results.

Science.gov (United States)

Simonsohn, Uri; Nelson, Leif D; Simmons, Joseph P

2014-11-01

Journals tend to publish only statistically significant evidence, creating a scientific record that markedly overstates the size of effects. We provide a new tool that corrects for this bias without requiring access to nonsignificant results. It capitalizes on the fact that the distribution of significant p values, p-curve, is a function of the true underlying effect. Researchers armed only with sample sizes and test results of the published findings can correct for publication bias. We validate the technique with simulations and by reanalyzing data from the Many-Labs Replication project. We demonstrate that p-curve can arrive at conclusions opposite that of existing tools by reanalyzing the meta-analysis of the "choice overload" literature. © The Author(s) 2014.

Helical CT findings of gastric wall thickening by peptic ulcer : compared with gastric adenocarcinoma with ulcer

International Nuclear Information System (INIS)

Jung, Won Jung; Choi, Jong Chul; Seo, Keum Soo; Koo, Bon Sik; Park, Byeong Ho; Kim, Chung Ku; Lee, Ki Nam; Nam, Kyung Jin

2000-01-01

To compare on the basis of helical CT findings gastric wall thickening of peptic gastric ulcer with that of gastric adenocarcinoma with ulcer. Thirty-eight patients with pathologically proven gastric lesion (17 cases of peptic ulcer and 21 cases of ulcerative or ulceroinfiltrative gastric cancer (Borrman type II, III) underwent helical CT, and the findings were retrospectively reviewed in terms of maximum abnormal wall thickness, preservation of the inner enhancing layer, the presence three discriminate layers of gastric wall, and enhancement pattern. The enhancement pattern of abnormally thick wall was compared with that of the portal phase of back muscle, and was defined as low, iso, or high. The Chi-square test and Student t test were used for statistical analysis. In cases of peptic ulcer and gastric cancer with ulceration, maximum abnormal wall thickness was 7-30 (mean, 16.1)mm, and 11-33 (mean, 21.8)mm, respectively. The inner enhancing layer was preserved in 15 of 17 patients (88.2%) and one of 21 (4.8%); three discriminate layers of gastric wall were observed in 8 of 17 patients (47.0%), and one of 21 (4.8%). The enhancement pattern was low in 12 of 17 patients (70.5%), and 3 of 21 (14.3%); iso in 4 of 17 (23.5%), and 4 of 21 (19.0%), and high in one of 17 (5.9%), and 14 of 21 (66.7%). All figures refer, respectively, to the two distinct conditions. In terms of preservation of the inner enhancing layer, three discriminate layers of gastric wall, and a low enhancement pattern, there were statistically significant differences between peptic ulcer and gastric adenocarcinoma with ulcer. Where the enhancement was high, however, the statistically significant difference between the two conditions was even greater. There was no statistically significant difference in terms of gastric wall thickness or iso-attenuation of thickened gastric. Helical CT findings of gastric wall thickening, preservation of the inner enhancing layer, and three discriminate layers of

Helical CT findings of gastric wall thickening by peptic ulcer : compared with gastric adenocarcinoma with ulcer

Energy Technology Data Exchange (ETDEWEB)

Jung, Won Jung; Choi, Jong Chul; Seo, Keum Soo; Koo, Bon Sik; Park, Byeong Ho; Kim, Chung Ku; Lee, Ki Nam; Nam, Kyung Jin [College of Medicine, Dong A University, Pusan (Korea, Republic of)

2000-02-01

To compare on the basis of helical CT findings gastric wall thickening of peptic gastric ulcer with that of gastric adenocarcinoma with ulcer. Thirty-eight patients with pathologically proven gastric lesion (17 cases of peptic ulcer and 21 cases of ulcerative or ulceroinfiltrative gastric cancer (Borrman type II, III)) underwent helical CT, and the findings were retrospectively reviewed in terms of maximum abnormal wall thickness, preservation of the inner enhancing layer, the presence three discriminate layers of gastric wall, and enhancement pattern. The enhancement pattern of abnormally thick wall was compared with that of the portal phase of back muscle, and was defined as low, iso, or high. The Chi-square test and Student t test were used for statistical analysis. In cases of peptic ulcer and gastric cancer with ulceration, maximum abnormal wall thickness was 7-30 (mean, 16.1)mm, and 11-33 (mean, 21.8)mm, respectively. The inner enhancing layer was preserved in 15 of 17 patients (88.2%) and one of 21 (4.8%); three discriminate layers of gastric wall were observed in 8 of 17 patients (47.0%), and one of 21 (4.8%). The enhancement pattern was low in 12 of 17 patients (70.5%), and 3 of 21 (14.3%); iso in 4 of 17 (23.5%), and 4 of 21 (19.0%), and high in one of 17 (5.9%), and 14 of 21 (66.7%). All figures refer, respectively, to the two distinct conditions. In terms of preservation of the inner enhancing layer, three discriminate layers of gastric wall, and a low enhancement pattern, there were statistically significant differences between peptic ulcer and gastric adenocarcinoma with ulcer. Where the enhancement was high, however, the statistically significant difference between the two conditions was even greater. There was no statistically significant difference in terms of gastric wall thickness or iso-attenuation of thickened gastric. Helical CT findings of gastric wall thickening, preservation of the inner enhancing layer, and three discriminate layers of

Evaluation of Solid Rocket Motor Component Data Using a Commercially Available Statistical Software Package

Science.gov (United States)

Stefanski, Philip L.

2015-01-01

Commercially available software packages today allow users to quickly perform the routine evaluations of (1) descriptive statistics to numerically and graphically summarize both sample and population data, (2) inferential statistics that draws conclusions about a given population from samples taken of it, (3) probability determinations that can be used to generate estimates of reliability allowables, and finally (4) the setup of designed experiments and analysis of their data to identify significant material and process characteristics for application in both product manufacturing and performance enhancement. This paper presents examples of analysis and experimental design work that has been conducted using Statgraphics®(Registered Trademark) statistical software to obtain useful information with regard to solid rocket motor propellants and internal insulation material. Data were obtained from a number of programs (Shuttle, Constellation, and Space Launch System) and sources that include solid propellant burn rate strands, tensile specimens, sub-scale test motors, full-scale operational motors, rubber insulation specimens, and sub-scale rubber insulation analog samples. Besides facilitating the experimental design process to yield meaningful results, statistical software has demonstrated its ability to quickly perform complex data analyses and yield significant findings that might otherwise have gone unnoticed. One caveat to these successes is that useful results not only derive from the inherent power of the software package, but also from the skill and understanding of the data analyst.

Evaluation of undergraduate nursing students' attitudes towards statistics courses, before and after a course in applied statistics.

Science.gov (United States)

Hagen, Brad; Awosoga, Olu; Kellett, Peter; Dei, Samuel Ofori

2013-09-01

Undergraduate nursing students must often take a course in statistics, yet there is scant research to inform teaching pedagogy. The objectives of this study were to assess nursing students' overall attitudes towards statistics courses - including (among other things) overall fear and anxiety, preferred learning and teaching styles, and the perceived utility and benefit of taking a statistics course - before and after taking a mandatory course in applied statistics. The authors used a pre-experimental research design (a one-group pre-test/post-test research design), by administering a survey to nursing students at the beginning and end of the course. The study was conducted at a University in Western Canada that offers an undergraduate Bachelor of Nursing degree. Participants included 104 nursing students, in the third year of a four-year nursing program, taking a course in statistics. Although students only reported moderate anxiety towards statistics, student anxiety about statistics had dropped by approximately 40% by the end of the course. Students also reported a considerable and positive change in their attitudes towards learning in groups by the end of the course, a potential reflection of the team-based learning that was used. Students identified preferred learning and teaching approaches, including the use of real-life examples, visual teaching aids, clear explanations, timely feedback, and a well-paced course. Students also identified preferred instructor characteristics, such as patience, approachability, in-depth knowledge of statistics, and a sense of humor. Unfortunately, students only indicated moderate agreement with the idea that statistics would be useful and relevant to their careers, even by the end of the course. Our findings validate anecdotal reports on statistics teaching pedagogy, although more research is clearly needed, particularly on how to increase students' perceptions of the benefit and utility of statistics courses for their nursing

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.

Basic statistical tools in research and data analysis

Directory of Open Access Journals (Sweden)

Zulfiqar Ali

2016-01-01

Full Text Available Statistical methods involved in carrying out a study include planning, designing, collecting data, analysing, drawing meaningful interpretation and reporting of the research findings. The statistical analysis gives meaning to the meaningless numbers, thereby breathing life into a lifeless data. The results and inferences are precise only if proper statistical tests are used. This article will try to acquaint the reader with the basic research tools that are utilised while conducting various studies. The article covers a brief outline of the variables, an understanding of quantitative and qualitative variables and the measures of central tendency. An idea of the sample size estimation, power analysis and the statistical errors is given. Finally, there is a summary of parametric and non-parametric tests used for data analysis.

A Model of Statistics Performance Based on Achievement Goal Theory.

Science.gov (United States)

Bandalos, Deborah L.; Finney, Sara J.; Geske, Jenenne A.

2003-01-01

Tests a model of statistics performance based on achievement goal theory. Both learning and performance goals affected achievement indirectly through study strategies, self-efficacy, and test anxiety. Implications of these findings for teaching and learning statistics are discussed. (Contains 47 references, 3 tables, 3 figures, and 1 appendix.)…

Official Statistics and Statistics Education: Bridging the Gap

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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.

Statistical processing of technological and radiochemical data

International Nuclear Information System (INIS)

Lahodova, Zdena; Vonkova, Kateřina

2011-01-01

The project described in this article had two goals. The main goal was to compare technological and radiochemical data from two units of nuclear power plant. The other goal was to check the collection, organization and interpretation of routinely measured data. Monitoring of analytical and radiochemical data is a very valuable source of knowledge for some processes in the primary circuit. Exploratory analysis of one-dimensional data was performed to estimate location and variability and to find extreme values, data trends, distribution, autocorrelation etc. This process allowed for the cleaning and completion of raw data. Then multiple analyses such as multiple comparisons, multiple correlation, variance analysis, and so on were performed. Measured data was organized into a data matrix. The results and graphs such as Box plots, Mahalanobis distance, Biplot, Correlation, and Trend graphs are presented in this article as statistical analysis tools. Tables of data were replaced with graphs because graphs condense large amounts of information into easy-to-understand formats. The significant conclusion of this work is that the collection and comprehension of data is a very substantial part of statistical processing. With well-prepared and well-understood data, its accurate evaluation is possible. Cooperation between the technicians who collect data and the statistician who processes it is also very important. (author)

Statistical shape analysis using 3D Poisson equation--A quantitatively validated approach.

Science.gov (United States)

Gao, Yi; Bouix, Sylvain

2016-05-01

Statistical shape analysis has been an important area of research with applications in biology, anatomy, neuroscience, agriculture, paleontology, etc. Unfortunately, the proposed methods are rarely quantitatively evaluated, and as shown in recent studies, when they are evaluated, significant discrepancies exist in their outputs. In this work, we concentrate on the problem of finding the consistent location of deformation between two population of shapes. We propose a new shape analysis algorithm along with a framework to perform a quantitative evaluation of its performance. Specifically, the algorithm constructs a Signed Poisson Map (SPoM) by solving two Poisson equations on the volumetric shapes of arbitrary topology, and statistical analysis is then carried out on the SPoMs. The method is quantitatively evaluated on synthetic shapes and applied on real shape data sets in brain structures. Copyright © 2016 Elsevier B.V. All rights reserved.

Empirical Tryout of a New Statistic for Detecting Temporally Inconsistent Responders.

Science.gov (United States)

Kerry, Matthew J

2018-01-01

Statistical screening of self-report data is often advised to support the quality of analyzed responses - For example, reduction of insufficient effort responding (IER). One recently introduced index based on Mahalanobis's D for detecting outliers in cross-sectional designs replaces centered scores with difference scores between repeated-measure items: Termed person temporal consistency ( D 2 ptc ). Although the adapted D 2 ptc index demonstrated usefulness in simulation datasets, it has not been applied to empirical data. The current study addresses D 2 ptc 's low uptake by critically appraising its performance across three empirical applications. Independent samples were selected to represent a range of scenarios commonly encountered by organizational researchers. First, in Sample 1, a repeat-measure of future time perspective (FTP) inexperienced working adults (age >40-years; n = 620) indicated that temporal inconsistency was significantly related to respondent age and item reverse-scoring. Second, in repeat-measure of team efficacy aggregations, D 2 ptc successfully detected team-level inconsistency across repeat-performance cycles. Thirdly, the usefulness of the D 2 ptc was examined in an experimental study dataset of subjective life expectancy indicated significantly more stable responding in experimental conditions compared to controls. The empirical findings support D 2 ptc 's flexible and useful application to distinct study designs. Discussion centers on current limitations and further extensions that may be of value to psychologists screening self-report data for strengthening response quality and meaningfulness of inferences from repeated-measures self-reports. Taken together, the findings support the usefulness of the newly devised statistic for detecting IER and other extreme response patterns.

Coexisting bronchogenic carcinoma and pulmonary tuberculosis in the same lobe: radiologic findings and clinical significance

International Nuclear Information System (INIS)

Kim, Young Il; Goo, Jin Mo; Im, Jung Gi; Kim, Hyae Young; Song, Jae Woo

2001-01-01

Bronchogenic carcinoma can mimic or be masked by pulmonary tuberculosis (TB), and the aim of this study was to describe the radiologic findings and clinical significance of bronchogenic carcinoma and pulmonary TB which coexist in the same lobe. The findings of 51 patients (48 males and three females, aged 48-79 years) in whom pulmonary TB and bronchogenic carcinoma coexisted in the same lobe were analyzed. The morphologic characteristics of a tumor, such as its diameter and margin, the presence of calcification or cavitation, and mediastinal lymphadenopathy, as seen at CT, were retrospectively assessed, and the clinical stage of the lung cancer was also determined. Using the serial chest radiographs available for 21 patients, the possible causes of delay in the diagnosis of lung cancer were analyzed. Lung cancers with coexisting pulmonary TB were located predominantly in the upper lobes (82.4%). The mean diameter of the mass was 5.3 cm, and most tumors (n=42, 82.4%) had a lobulated border. Calcification within the tumor was seen in 20 patients (39.2%), and cavitation in five (9.8%). Forty-two (82.4%) had mediastinal lymphadenopathy, and more than half the tumors (60.8%) were at an advanced stage [IIIB (n=11) or IV (n=20)]. The average delay in diagnosing lung cancer was 11.7 (range, 1-24) months, and the causes of this were failure to observe new nodules masked by coexisting stable TB lesions (n=8), misinterpretation of new lesions as aggravation of TB (n=5), misinterpretation of lung cancer as tuberculoma at initial radiography (n=4), masking of the nodule by an active TB lesion (n=3), and subtleness of the lesion (n=1). Most cancers concurrent with TB are large, lobulated masses with mediastinal lymphadenopathy, indicating that the morphologic characteristics of lung cancer with coexisting pulmonary TB are similar to those of lung cancer without TB. The diagnosis of lung cancer is delayed mainly because of masking by a tuberculous lesion, and this suggests that

Non-identical anyons and new statistics for spinons and holons

International Nuclear Information System (INIS)

Mor, T.

1993-01-01

We discuss the various existing proposals for the statistics of holons and spinons (the proposed fundamental excitations of the tJ model for HTSC), and we present new anyonic alternatives. We generalize Wilczek's realization of anyons to include non-identical anyons with mutual statistics and concentrate on particular cases which preserve time-reversal symmetry. Under the restriction of time-reversal symmetry, we find two additional possibilities for the statistics of holons and spinons - either both holons and spinons are bosons or both are fermions. In addition they obey an antisymmetric mutual statistics. We discuss the pairing mechanism of holons in this model, and the microscopic origins for this statistical behavior. (orig.)

Multivariate statistical analysis to investigate the subduction zone parameters favoring the occurrence of giant megathrust earthquakes

Science.gov (United States)

Brizzi, S.; Sandri, L.; Funiciello, F.; Corbi, F.; Piromallo, C.; Heuret, A.

2018-03-01

The observed maximum magnitude of subduction megathrust earthquakes is highly variable worldwide. One key question is which conditions, if any, favor the occurrence of giant earthquakes (Mw ≥ 8.5). Here we carry out a multivariate statistical study in order to investigate the factors affecting the maximum magnitude of subduction megathrust earthquakes. We find that the trench-parallel extent of subduction zones and the thickness of trench sediments provide the largest discriminating capability between subduction zones that have experienced giant earthquakes and those having significantly lower maximum magnitude. Monte Carlo simulations show that the observed spatial distribution of giant earthquakes cannot be explained by pure chance to a statistically significant level. We suggest that the combination of a long subduction zone with thick trench sediments likely promotes a great lateral rupture propagation, characteristic of almost all giant earthquakes.

Topology for statistical modeling of petascale data.

Energy Technology Data Exchange (ETDEWEB)

Pascucci, Valerio (University of Utah, Salt Lake City, UT); Mascarenhas, Ajith Arthur; Rusek, Korben (Texas A& M University, College Station, TX); Bennett, Janine Camille; Levine, Joshua (University of Utah, Salt Lake City, UT); Pebay, Philippe Pierre; Gyulassy, Attila (University of Utah, Salt Lake City, UT); Thompson, David C.; Rojas, Joseph Maurice (Texas A& M University, College Station, TX)

2011-07-01

This document presents current technical progress and dissemination of results for the Mathematics for Analysis of Petascale Data (MAPD) project titled 'Topology for Statistical Modeling of Petascale Data', funded by the Office of Science Advanced Scientific Computing Research (ASCR) Applied Math program. Many commonly used algorithms for mathematical analysis do not scale well enough to accommodate the size or complexity of petascale data produced by computational simulations. The primary goal of this project is thus to develop new mathematical tools that address both the petascale size and uncertain nature of current data. At a high level, our approach is based on the complementary techniques of combinatorial topology and statistical modeling. In particular, we use combinatorial topology to filter out spurious data that would otherwise skew statistical modeling techniques, and we employ advanced algorithms from algebraic statistics to efficiently find globally optimal fits to statistical models. This document summarizes the technical advances we have made to date that were made possible in whole or in part by MAPD funding. These technical contributions can be divided loosely into three categories: (1) advances in the field of combinatorial topology, (2) advances in statistical modeling, and (3) new integrated topological and statistical methods.

The significance of MR cisternography in the evaluation of cerebrospinal rhinorrhea

International Nuclear Information System (INIS)

Xian Junfang; Wang Zhenchang; Liang Xihong; Tong Yajian; Zhao Bo; Zhou Bing; Ge Wentong; Zhang Tianming

2005-01-01

Objective: To assess the ability of MR cisternography (MRC) in the diagnosis of cerebrospinal rhinorrhea, and compare the advantages and disadvantages of MRC, CT cisternography (CTC) and high-resolution CT (HRCT). Methods: HRCT and MRC were performed in 18 cases with clinically suspected cerebrospinal rhinorrhea. Ten cases also underwent CTC successfully. Compared with surgical findings, the accuracy of the three methods was analysed. Results: Operative findings demonstrated 29 fistulae in all 18 cases with clinically suspected cerebrospinal rhinorrhea. Twenty-five fistulae were showed on preoperative HRCT in all 18 cases, of which 18 fistulae were consistent with operative findings, with an accuracy of 18/29. Twenty-four fistulae were displayed on preoperative MRC in all 18 cases, of which 21 fistulae were consistent with operative findings, with an accuracy of 21/29. In the ten cases undergone preoperative CTC, surgical findings showed 18 fistulae. CTC of 10 cases demonstrated 12 fistulae, of which 11 fistulae were consistent with operative findings, with an accuracy of 11/18. By way of statistical analysis, there was no significant difference between three methods in the diagnosis of cerebrospinal rhinorrhea (P>0.05). Conclusion: HRCT and MRC appeared to be a noninvasively feasible examination method. The combination of HRCT and MRC was highly accurate in the evaluation of suspected cerebrospinal rhinorrhea and in the location of the site of cerebrospinal rhinorrhea that should be considered as a viable alternative to invasively time-consuming CTC. (authors)

Computer tomographic findings in portal hypertension due to cirrhosis of the liver. Pt. 1

International Nuclear Information System (INIS)

Koester, O.; Kunz, R.; Fischer, P.; Lackner, K.; Koischwitz, D.; Bonn Univ.

1983-01-01

The CT findings in 80 patients with confirmed portal hypertension due to intrahepatic block were analysed retrospectively. The findings included ascites, hypo-dense areas in the liver, nodular or irregular liver contour, the inability of define intrahepatic portal vessels with narrow window settings, the so-called ''kissing'' sign and evidence of hepato-fugal collaterals and thickning of the wall of the oesophagus. Electronic measurements of various organs (liver, spleen) and vessel diameters (portal vein, superior mesenteric vein) provide parameters which permit classification of patients into the cirrhotic group, as compared with a control group. The statistical significance of this classification was checked by the Kolmogoroff-Smirnoff test. (orig.)

Computer tomographic findings in portal hypertension due to cirrhosis of the liver. Pt. 1

Energy Technology Data Exchange (ETDEWEB)

Koester, O; Kunz, R; Fischer, P; Lackner, K; Koischwitz, D

1983-06-01

The CT findings in 80 patients with confirmed portal hypertension due to intrahepatic block were analysed retrospectively. The findings included ascites, hypo-dense areas in the liver, nodular or irregular liver contour, the inability of define intrahepatic portal vessels with narrow window settings, the so-called ''kissing'' sign and evidence of hepato-fugal collaterals and thickening of the wall of the oesophagus. Electronic measurements of various organs (liver, spleen) and vessel diameters (portal vein, superior mesenteric vein) provide parameters which permit classification of patients into the cirrhotic group, as compared with a control group. The statistical significance of this classification was checked by the Kolmogoroff-Smirnoff test.

Statistics available for site studies in registers and surveys at Statistics Sweden

Energy Technology Data Exchange (ETDEWEB)

Haldorson, Marie [Statistics Sweden, Oerebro (Sweden)

2000-03-01

Statistics Sweden (SCB) has produced this report on behalf of the Swedish Nuclear Fuel and Waste Management Company (SKB), as part of the data to be used by SKB in conducting studies of potential sites. The report goes over the statistics obtainable from SCB in the form of registers and surveys. The purpose is to identify the variables that are available, and to specify their degree of geographical detail and the time series that are available. Chapter two describes the statistical registers available at SCB, registers that share the common feature that they provide total coverage, i.e. they contain all 'objects' of a given type, such as population, economic activities (e.g. from statements of employees' earnings provided to the tax authorities), vehicles, enterprises or real estate. SCB has exclusive responsibility for seven of the nine registers included in the chapter, while two registers are ordered by public authorities with statistical responsibilities. Chapter three describes statistical surveys that are conducted by SCB, with the exception of the National Forest Inventory, which is carried out by the Swedish University of Agricultural Sciences. In terms of geographical breakdown, the degree of detail in the surveys varies, but all provide some possibility of reporting data at lower than the national level. The level involved may be county, municipality, yield district, coastal district or category of enterprises, e.g. aquaculture. Six of the nine surveys included in the chapter have been ordered by public authorities with statistical responsibilities, while SCB has exclusive responsibility for the others. Chapter four presents an overview of the statistics on land use maintained by SCB. This chapter does not follow the same pattern as chapters two and three but instead gives a more general account. The conclusion can be drawn that there are good prospects that SKB can make use of SCB's data as background information or in other ways when

Statistics available for site studies in registers and surveys at Statistics Sweden

International Nuclear Information System (INIS)

Haldorson, Marie

2000-03-01

Statistics Sweden (SCB) has produced this report on behalf of the Swedish Nuclear Fuel and Waste Management Company (SKB), as part of the data to be used by SKB in conducting studies of potential sites. The report goes over the statistics obtainable from SCB in the form of registers and surveys. The purpose is to identify the variables that are available, and to specify their degree of geographical detail and the time series that are available. Chapter two describes the statistical registers available at SCB, registers that share the common feature that they provide total coverage, i.e. they contain all 'objects' of a given type, such as population, economic activities (e.g. from statements of employees' earnings provided to the tax authorities), vehicles, enterprises or real estate. SCB has exclusive responsibility for seven of the nine registers included in the chapter, while two registers are ordered by public authorities with statistical responsibilities. Chapter three describes statistical surveys that are conducted by SCB, with the exception of the National Forest Inventory, which is carried out by the Swedish University of Agricultural Sciences. In terms of geographical breakdown, the degree of detail in the surveys varies, but all provide some possibility of reporting data at lower than the national level. The level involved may be county, municipality, yield district, coastal district or category of enterprises, e.g. aquaculture. Six of the nine surveys included in the chapter have been ordered by public authorities with statistical responsibilities, while SCB has exclusive responsibility for the others. Chapter four presents an overview of the statistics on land use maintained by SCB. This chapter does not follow the same pattern as chapters two and three but instead gives a more general account. The conclusion can be drawn that there are good prospects that SKB can make use of SCB's data as background information or in other ways when undertaking future

Statistics available for site studies in registers and surveys at Statistics Sweden

Energy Technology Data Exchange (ETDEWEB)

Haldorson, Marie [Statistics Sweden, Oerebro (Sweden)

2000-03-01

Statistics Sweden (SCB) has produced this report on behalf of the Swedish Nuclear Fuel and Waste Management Company (SKB), as part of the data to be used by SKB in conducting studies of potential sites. The report goes over the statistics obtainable from SCB in the form of registers and surveys. The purpose is to identify the variables that are available, and to specify their degree of geographical detail and the time series that are available. Chapter two describes the statistical registers available at SCB, registers that share the common feature that they provide total coverage, i.e. they contain all 'objects' of a given type, such as population, economic activities (e.g. from statements of employees' earnings provided to the tax authorities), vehicles, enterprises or real estate. SCB has exclusive responsibility for seven of the nine registers included in the chapter, while two registers are ordered by public authorities with statistical responsibilities. Chapter three describes statistical surveys that are conducted by SCB, with the exception of the National Forest Inventory, which is carried out by the Swedish University of Agricultural Sciences. In terms of geographical breakdown, the degree of detail in the surveys varies, but all provide some possibility of reporting data at lower than the national level. The level involved may be county, municipality, yield district, coastal district or category of enterprises, e.g. aquaculture. Six of the nine surveys included in the chapter have been ordered by public authorities with statistical responsibilities, while SCB has exclusive responsibility for the others. Chapter four presents an overview of the statistics on land use maintained by SCB. This chapter does not follow the same pattern as chapters two and three but instead gives a more general account. The conclusion can be drawn that there are good prospects that SKB can make use of SCB's data as background information or in other ways when undertaking future

Comparison of MRI findings with clinical symptoms in temporomandibular joint internal derangement

Energy Technology Data Exchange (ETDEWEB)

Kwon, Ki Jeong [Chonbuk National University College of Medicine, Gwangju (Korea, Republic of)

2005-06-15

To determine the clinical correlation of magnetic resonance imaging (MRI) findings of temporomandibular joint internal derangements. The MR images of 150 TMJs in 75 patients were analyzed. The clinical symptoms were pain in the pre auricular area and masticatory muscles and TMJ sounds. There was a statistically significant relationship between the MRI diagnoses of different types of disc displacements and clinical findings of pain, clicking, and crepitus. The risk of TMJ pain was increased when the disc displacement without reduction occurred at the same time in combination with the osteoarthrosis and effusion. Regardless of the results, the data indicate that each of these MR imaging variables may not be regarded as the unique and dominant factor in defining TMJ pain occurrence.

Accident statistics and the human-factor element.

Science.gov (United States)

Shuckburgh, J S

1975-01-01

The number of fatal accidents involving public transport aircraft has increased significantly in recent years and, because more and more "wide-bodied" aircraft have been coming into service, this has resulted in a rapid increase in the number of fatalities. A combined attack on the problem by all concerned with flight safety is required to improve the situation. The collection and analysis of aircraft accident data can contribute to safety in two ways; by giving an indication of where to concentrate future effort and by showing how successful past efforts have been. An analysis of worldwide accident statistics by phase of flight and causal factor show that the largest percentage of accidents occurs in the approach and landing phase and are caused by "pilot error". Further research is needed to find out why pilots make errors and how such errors can be eliminated.

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

On the significance of δ13C correlations in ancient sediments

Science.gov (United States)

Derry, Louis A.

2010-08-01

A graphical analysis of the correlations between δc and ɛTOC was introduced by Rothman et al. (2003) to obtain estimates of the carbon isotopic composition of inputs to the oceans and the organic carbon burial fraction. Applied to Cenozoic data, the method agrees with independent estimates, but with Neoproterozoic data the method yields results that cannot be accommodated with standard models of sedimentary carbon isotope mass balance. We explore the sensitivity of the graphical correlation method and find that the variance ratio between δc and δo is an important control on the correlation of δc and ɛ. If the variance ratio σc/ σo ≥ 1 highly correlated arrays very similar to those obtained from the data are produced from independent random variables. The Neoproterozoic data shows such variance patterns, and the regression parameters for the Neoproterozoic data are statistically indistinguishable from the randomized model at the 95% confidence interval. The projection of the data into δc- ɛ space cannot distinguish between signal and noise, such as post-depositional alteration, under these circumstances. There appears to be no need to invoke unusual carbon cycle dynamics to explain the Neoproterozoic δc- ɛ array. The Cenozoic data have σc/ σo vs. ɛ correlation is probably geologically significant, but the analyzed sample size is too small to yield statistically significant results.

Journal Data Sharing Policies and Statistical Reporting Inconsistencies in Psychology

Directory of Open Access Journals (Sweden)

Michèle B. Nuijten

2017-12-01

Full Text Available In this paper, we present three retrospective observational studies that investigate the relation between data sharing and statistical reporting inconsistencies. Previous research found that reluctance to share data was related to a higher prevalence of statistical errors, often in the direction of statistical significance (Wicherts, Bakker, & Molenaar, 2011. We therefore hypothesized that journal policies about data sharing and data sharing itself would reduce these inconsistencies. In Study 1, we compared the prevalence of reporting inconsistencies in two similar journals on decision making with different data sharing policies. In Study 2, we compared reporting inconsistencies in psychology articles published in PLOS journals (with a data sharing policy and Frontiers in Psychology (without a stipulated data sharing policy. In Study 3, we looked at papers published in the journal Psychological Science to check whether papers with or without an Open Practice Badge differed in the prevalence of reporting errors. Overall, we found no relationship between data sharing and reporting inconsistencies. We did find that journal policies on data sharing seem extremely effective in promoting data sharing. We argue that open data is essential in improving the quality of psychological science, and we discuss ways to detect and reduce reporting inconsistencies in the literature.

SIGNIFICANT INFLUENCES OF VIOLIN EXTRACURRICULAR ACHIEVEMENT TO EMOTIONAL INTELLIGENCE

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Nafik

2014-06-01

Full Text Available This research aims to find out (1 whether there is an influence between student’s achievements of learning violin toward their emotional intelligence, (2 whether there is a correlation between student’s achievement of learning violin and their emotional intelligence, and (3 how much contribution of student’s achievement of learning violin to their emotional intelligence. It is a qualitative research which is defined as a research method based on positivism philosophy which is used to study particular sample and population. The sample and population are drawn randomly using research instruments to collect data, and the data are analyzed statistically. This aims to examine the hypothesis defined. The finding shows that there is a significant influence between student’s achievement of learning violin and their emotional intelligence about 76.1%, while the rest of it 23.9% is influenced by other factors which are not studied in this research. It proves that learning violin influences student’s emotional intelligence very much and emotional intelligence is influential in increasing student’s achievement. From the data, it shows that most of the students participating in violin extracurricular are able to increase their learning achievement.

Intracerebral metastasis showing restricted diffusion: Correlation with histopathologic findings

Energy Technology Data Exchange (ETDEWEB)

Duygulu, G. [Radiology Department, Ege University Medicine School, Izmir (Turkey); Ovali, G. Yilmaz [Radiology Department, Celal Bayar University Medicine School, Manisa (Turkey)], E-mail: gulgun.yilmaz@bayar.edu.tr; Calli, C.; Kitis, O.; Yuenten, N. [Radiology Department, Ege University Medicine School, Izmir (Turkey); Akalin, T. [Pathology Department, Ege University Medicine School, Izmir (Turkey); Islekel, S. [Neurosurgery Department, Ege University Medicine School, Izmir (Turkey)

2010-04-15

Objective: We aimed to detect the frequency of restricted diffusion in intracerebral metastases and to find whether there is correlation between the primary tumor pathology and diffusion-weighted MR imaging (DWI) findings of these metastases. Material and methods: 87 patients with intracerebral metastases were examined with routine MR imaging and DWI. 11 hemorrhagic metastatic lesions were excluded. The routine MR imaging included three plans before and after contrast enhancement. The DWI was performed with spin-echo EPI sequence with three b values (0, 500 and 1000), and ADC maps were calculated. 76 patients with metastases were grouped according to primary tumor histology and the ratios of restricted diffusion were calculated according to these groups. ADCmin values were measured within the solid components of the tumors and the ratio of metastases with restricted diffusion to that which do not show restricted diffusion were calculated. Fisher's exact and Mann-Whitney U tests were used for the statistical analysis. Results: Restricted diffusion was observed in a total of 15 metastatic lesions (19, 7%). Primary malignancy was lung carcinoma in 10 of these cases (66, 6%) (5 small cell carcinoma, 5 non-small cell carcinoma), and breast carcinoma in three cases (20%). Colon carcinoma and testicular teratocarcinoma were the other two primary tumors in which restricted diffusion in metastasis was detected. There was no statistical significant difference between the primary pathology groups which showed restricted diffusion (p > 0.05). ADCmin values of solid components of the metastasis with restricted diffusion and other metastasis without restricted diffusion also showed no significant statistical difference (0.72 {+-} 0.16 x 10{sup -3} mm{sup 2}/s and 0.78 {+-} 21 x 10{sup -3} mm{sup 2}/s respectively) (p = 0.325). Conclusion: Detection of restricted diffusion on DWI in intracerebral metastasis is not rare, particularly if the primary tumor is lung or breast

Exclusion Statistics in Conformal Field Theory Spectra

International Nuclear Information System (INIS)

Schoutens, K.

1997-01-01

We propose a new method for investigating the exclusion statistics of quasiparticles in conformal field theory (CFT) spectra. The method leads to one-particle distribution functions, which generalize the Fermi-Dirac distribution. For the simplest SU(n) invariant CFTs we find a generalization of Gentile parafermions, and we obtain new distributions for the simplest Z N -invariant CFTs. In special examples, our approach reproduces distributions based on 'fractional exclusion statistics' in the sense of Haldane. We comment on applications to fractional quantum Hall effect edge theories. copyright 1997 The American Physical Society

MR imaging diagnosis of posterior cruciate ligament injury: importance of ancillary findings

International Nuclear Information System (INIS)

Hwang, Kang Ik; Lee, Jong Hwa; Kim, Young Sun; Lee, Jung Hwoi; Ki, Tae Sung; Park, Jong Oag

1997-01-01

To evaluate the importance of two ancillary findings of anterior tibial plateau bruise/fracture and popliteus muscle strain on MR diagnosis of posterior cruicate ligament injury. We retrospectively evaluated 48 patients with confirmed posterior cruciate ligament tear. We studied the incidence of anterior tibial plateau injury and popliteus muscle strain, and the specificity of popliteus muscle strain with or without bony injury. A complete tear of the posterior cruciate ligament was noted in 37 cases, a partial tear in 11. Anterior tibial plateau lesion was found in 21 of 48 cases (44%); This total was made up of 17/37 PCL complete tears (46%) and 4/11 partial tears (36%). The difference in the incidence of complete and partial tears is not statistically significant. Popliteus muscle injury was found in 20 of 48 cases (42%), the total consisted of 19/37 PCL complete tears (51%) and 1/11 partial tears (10%). The incidence of 42% is relatively high, approximating that of bony injury. The difference in the incidence of complete and partial tears is statistically significant (p < 0.006). Specificity for posterior cruciate ligament tear is 69%(20/29), and when concomitant with anterior tibial plateau injury is 94%(16/17). As in the case of anterior cruciate ligament injury, these documented ancillary findings of anterior tibial plateau and popliteus muscle injuries are very helpful when MR diagnosis of posterior cruciate ligament injury itself and differentiation of partial and complete rupture are doubtful

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

An application of an optimal statistic for characterizing relative orientations

Science.gov (United States)

Jow, Dylan L.; Hill, Ryley; Scott, Douglas; Soler, J. D.; Martin, P. G.; Devlin, M. J.; Fissel, L. M.; Poidevin, F.

2018-02-01

We present the projected Rayleigh statistic (PRS), a modification of the classic Rayleigh statistic, as a test for non-uniform relative orientation between two pseudo-vector fields. In the application here, this gives an effective way of investigating whether polarization pseudo-vectors (spin-2 quantities) are preferentially parallel or perpendicular to filaments in the interstellar medium. For example, there are other potential applications in astrophysics, e.g. when comparing small-scale orientations with larger scale shear patterns. We compare the efficiency of the PRS against histogram binning methods that have previously been used for characterizing the relative orientations of gas column density structures with the magnetic field projected on the plane of the sky. We examine data for the Vela C molecular cloud, where the column density is inferred from Herschel submillimetre observations, and the magnetic field from observations by the Balloon-borne Large-Aperture Submillimetre Telescope in the 250-, 350- and 500-μm wavelength bands. We find that the PRS has greater statistical power than approaches that bin the relative orientation angles, as it makes more efficient use of the information contained in the data. In particular, the use of the PRS to test for preferential alignment results in a higher statistical significance, in each of the four Vela C regions, with the greatest increase being by a factor 1.3 in the South-Nest region in the 250 - μ m band.

Nonparametric statistical inference

CERN Document Server

Gibbons, Jean Dickinson

2014-01-01

Thoroughly revised and reorganized, the fourth edition presents in-depth coverage of the theory and methods of the most widely used nonparametric procedures in statistical analysis and offers example applications appropriate for all areas of the social, behavioral, and life sciences. The book presents new material on the quantiles, the calculation of exact and simulated power, multiple comparisons, additional goodness-of-fit tests, methods of analysis of count data, and modern computer applications using MINITAB, SAS, and STATXACT. It includes tabular guides for simplified applications of tests and finding P values and confidence interval estimates.

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.

Interdisciplinary applications of statistical physics to complex systems: Seismic physics, econophysics, and sociophysics

Science.gov (United States)

Tenenbaum, Joel

This thesis applies statistical physics concepts and methods to quantitatively analyze complex systems. This thesis is separated into four parts: (i) characteristics of earthquake systems (ii) memory and volatility in data time series (iii) the application of part (ii) to world financial markets, and (iv) statistical observations on the evolution of word usage. In Part I, we observe statistical patterns in the occurrence of earthquakes. We select a 14-year earthquake catalog covering the archipelago of Japan. We find that regions traditionally thought of as being too distant from one another for causal contact display remarkably high correlations, and the networks that result have a tendency to link highly connected areas with other highly connected areas. In Part II, we introduce and apply the concept of "volatility asymmetry", the primary use of which is in financial data. We explain the relation between memory and "volatility asymmetry" in terms of an asymmetry parameter lambda. We define a litmus test for determining whether lambda is statistically significant and propose a stochastic model based on this parameter and use the model to further explain empirical data. In Part III, we expand on volatility asymmetry. Importing the concepts of time dependence and universality from physics, we explore the aspects of emerging (or "transition") economies in Eastern Europe as they relate to asymmetry. We find that these emerging markets in some instances behave like developed markets and in other instances do not, and that the distinction is a matter both of country and a matter of time period, crisis periods showing different asymmetry characteristics than "healthy" periods. In Part IV, we take note of a series of findings in econophysics, showing statistical growth similarities between a variety of different areas that all have in common the fact of taking place in areas that are both (i) competing and (ii) dynamic. We show that this same growth distribution can be

Quantum formalism for classical statistics

Science.gov (United States)

Wetterich, C.

2018-06-01

In static classical statistical systems the problem of information transport from a boundary to the bulk finds a simple description in terms of wave functions or density matrices. While the transfer matrix formalism is a type of Heisenberg picture for this problem, we develop here the associated Schrödinger picture that keeps track of the local probabilistic information. The transport of the probabilistic information between neighboring hypersurfaces obeys a linear evolution equation, and therefore the superposition principle for the possible solutions. Operators are associated to local observables, with rules for the computation of expectation values similar to quantum mechanics. We discuss how non-commutativity naturally arises in this setting. Also other features characteristic of quantum mechanics, such as complex structure, change of basis or symmetry transformations, can be found in classical statistics once formulated in terms of wave functions or density matrices. We construct for every quantum system an equivalent classical statistical system, such that time in quantum mechanics corresponds to the location of hypersurfaces in the classical probabilistic ensemble. For suitable choices of local observables in the classical statistical system one can, in principle, compute all expectation values and correlations of observables in the quantum system from the local probabilistic information of the associated classical statistical system. Realizing a static memory material as a quantum simulator for a given quantum system is not a matter of principle, but rather of practical simplicity.

Primordial statistical anisotropy generated at the end of inflation

International Nuclear Information System (INIS)

Yokoyama, Shuichiro; Soda, Jiro

2008-01-01

We present a new mechanism for generating primordial statistical anisotropy of curvature perturbations. We introduce a vector field which has a non-minimal kinetic term and couples with a waterfall field in a hybrid inflation model. In such a system, the vector field gives fluctuations of the end of inflation and hence induces a subcomponent of curvature perturbations. Since the vector has a preferred direction, the statistical anisotropy could appear in the fluctuations. We present the explicit formula for the statistical anisotropy in the primordial power spectrum and the bispectrum of curvature perturbations. Interestingly, there is the possibility that the statistical anisotropy does not appear in the power spectrum but does appear in the bispectrum. We also find that the statistical anisotropy provides the shape dependence to the bispectrum

Primordial statistical anisotropy generated at the end of inflation

Energy Technology Data Exchange (ETDEWEB)

Yokoyama, Shuichiro [Department of Physics and Astrophysics, Nagoya University, Aichi 464-8602 (Japan); Soda, Jiro, E-mail: shu@a.phys.nagoya-u.ac.jp, E-mail: jiro@tap.scphys.kyoto-u.ac.jp [Department of Physics, Kyoto University, Kyoto 606-8501 (Japan)

2008-08-15

We present a new mechanism for generating primordial statistical anisotropy of curvature perturbations. We introduce a vector field which has a non-minimal kinetic term and couples with a waterfall field in a hybrid inflation model. In such a system, the vector field gives fluctuations of the end of inflation and hence induces a subcomponent of curvature perturbations. Since the vector has a preferred direction, the statistical anisotropy could appear in the fluctuations. We present the explicit formula for the statistical anisotropy in the primordial power spectrum and the bispectrum of curvature perturbations. Interestingly, there is the possibility that the statistical anisotropy does not appear in the power spectrum but does appear in the bispectrum. We also find that the statistical anisotropy provides the shape dependence to the bispectrum.

The efficacy of adult christian support groups in coping with the death of a significant loved one.

Science.gov (United States)

Goodman, Herbert; Stone, Mark H

2009-09-01

Psychologists sometimes minimize important resources such as religion and spiritual beliefs for coping with bereavement. Alienation of therapeutic psychology from religious values contrasts to professional and public interest in religious experience and commitment. A supportive viewpoint has come about partially as a result of recognizing important values which clinicians have found absent in many of their clients. Until spiritual belief systems become integrated into the work of clinicians, clients may not be fully integrative in coping with loss. The key finding of this study was that individuals who participated in Christian and secular support groups showed no statistically significant difference in their mean endorsement of negative criteria on the BHS, and no statistically significant difference for their mean score endorsement of positive criteria on the RCOPE. However, a Christian-oriented approach was no less effective than a psychological-oriented one. In both groups, a spiritual connection to a specific or generalized higher power was frequently identified which clients ascribed to facilitating the management of their coping.

Online Statistical Modeling (Regression Analysis) for Independent Responses

Science.gov (United States)

Made Tirta, I.; Anggraeni, Dian; Pandutama, Martinus

2017-06-01

Regression analysis (statistical analmodelling) are among statistical methods which are frequently needed in analyzing quantitative data, especially to model relationship between response and explanatory variables. Nowadays, statistical models have been developed into various directions to model various type and complex relationship of data. Rich varieties of advanced and recent statistical modelling are mostly available on open source software (one of them is R). However, these advanced statistical modelling, are not very friendly to novice R users, since they are based on programming script or command line interface. Our research aims to developed web interface (based on R and shiny), so that most recent and advanced statistical modelling are readily available, accessible and applicable on web. We have previously made interface in the form of e-tutorial for several modern and advanced statistical modelling on R especially for independent responses (including linear models/LM, generalized linier models/GLM, generalized additive model/GAM and generalized additive model for location scale and shape/GAMLSS). In this research we unified them in the form of data analysis, including model using Computer Intensive Statistics (Bootstrap and Markov Chain Monte Carlo/ MCMC). All are readily accessible on our online Virtual Statistics Laboratory. The web (interface) make the statistical modeling becomes easier to apply and easier to compare them in order to find the most appropriate model for the data.

Brief guidelines for methods and statistics in medical research

CERN Document Server

Ab Rahman, Jamalludin

2015-01-01

This book serves as a practical guide to methods and statistics in medical research. It includes step-by-step instructions on using SPSS software for statistical analysis, as well as relevant examples to help those readers who are new to research in health and medical fields. Simple texts and diagrams are provided to help explain the concepts covered, and print screens for the statistical steps and the SPSS outputs are provided, together with interpretations and examples of how to report on findings. Brief Guidelines for Methods and Statistics in Medical Research offers a valuable quick reference guide for healthcare students and practitioners conducting research in health related fields, written in an accessible style.

Semi-Poisson statistics in quantum chaos.

Science.gov (United States)

García-García, Antonio M; Wang, Jiao

2006-03-01

We investigate the quantum properties of a nonrandom Hamiltonian with a steplike singularity. It is shown that the eigenfunctions are multifractals and, in a certain range of parameters, the level statistics is described exactly by semi-Poisson statistics (SP) typical of pseudointegrable systems. It is also shown that our results are universal, namely, they depend exclusively on the presence of the steplike singularity and are not modified by smooth perturbations of the potential or the addition of a magnetic flux. Although the quantum properties of our system are similar to those of a disordered conductor at the Anderson transition, we report important quantitative differences in both the level statistics and the multifractal dimensions controlling the transition. Finally, the study of quantum transport properties suggests that the classical singularity induces quantum anomalous diffusion. We discuss how these findings may be experimentally corroborated by using ultracold atoms techniques.

Applied statistics for economics and business

CERN Document Server

Özdemir, Durmuş

2016-01-01

This textbook introduces readers to practical statistical issues by presenting them within the context of real-life economics and business situations. It presents the subject in a non-threatening manner, with an emphasis on concise, easily understandable explanations. It has been designed to be accessible and student-friendly and, as an added learning feature, provides all the relevant data required to complete the accompanying exercises and computing problems, which are presented at the end of each chapter. It also discusses index numbers and inequality indices in detail, since these are of particular importance to students and commonly omitted in textbooks. Throughout the text it is assumed that the student has no prior knowledge of statistics. It is aimed primarily at business and economics undergraduates, providing them with the basic statistical skills necessary for further study of their subject. However, students of other disciplines will also find it relevant.

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

Science.gov (United States)

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

THE ABSOLUTE MAGNITUDE OF RRc VARIABLES FROM STATISTICAL PARALLAX

Energy Technology Data Exchange (ETDEWEB)

Kollmeier, Juna A.; Burns, Christopher R.; Thompson, Ian B.; Preston, George W.; Crane, Jeffrey D.; Madore, Barry F.; Morrell, Nidia; Prieto, José L.; Shectman, Stephen; Simon, Joshua D.; Villanueva, Edward [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Szczygieł, Dorota M.; Gould, Andrew [Department of Astronomy, The Ohio State University, 4051 McPherson Laboratory, Columbus, OH 43210 (United States); Sneden, Christopher [Department of Astronomy, University of Texas at Austin, TX 78712 (United States); Dong, Subo [Institute for Advanced Study, 500 Einstein Drive, Princeton, NJ 08540 (United States)

2013-09-20

We present the first definitive measurement of the absolute magnitude of RR Lyrae c-type variable stars (RRc) determined purely from statistical parallax. We use a sample of 242 RRc variables selected from the All Sky Automated Survey for which high-quality light curves, photometry, and proper motions are available. We obtain high-resolution echelle spectra for these objects to determine radial velocities and abundances as part of the Carnegie RR Lyrae Survey. We find that M{sub V,RRc} = 0.59 ± 0.10 at a mean metallicity of [Fe/H] = –1.59. This is to be compared with previous estimates for RRab stars (M{sub V,RRab} = 0.76 ± 0.12) and the only direct measurement of an RRc absolute magnitude (RZ Cephei, M{sub V,RRc} = 0.27 ± 0.17). We find the bulk velocity of the halo relative to the Sun to be (W{sub π}, W{sub θ}, W{sub z} ) = (12.0, –209.9, 3.0) km s{sup –1} in the radial, rotational, and vertical directions with dispersions (σ{sub W{sub π}},σ{sub W{sub θ}},σ{sub W{sub z}}) = (150.4, 106.1, 96.0) km s{sup -1}. For the disk, we find (W{sub π}, W{sub θ}, W{sub z} ) = (13.0, –42.0, –27.3) km s{sup –1} relative to the Sun with dispersions (σ{sub W{sub π}},σ{sub W{sub θ}},σ{sub W{sub z}}) = (67.7,59.2,54.9) km s{sup -1}. Finally, as a byproduct of our statistical framework, we are able to demonstrate that UCAC2 proper-motion errors are significantly overestimated as verified by UCAC4.

Ontologies and tag-statistics

Science.gov (United States)

Tibély, Gergely; Pollner, Péter; Vicsek, Tamás; Palla, Gergely

2012-05-01

Due to the increasing popularity of collaborative tagging systems, the research on tagged networks, hypergraphs, ontologies, folksonomies and other related concepts is becoming an important interdisciplinary area with great potential and relevance for practical applications. In most collaborative tagging systems the tagging by the users is completely ‘flat’, while in some cases they are allowed to define a shallow hierarchy for their own tags. However, usually no overall hierarchical organization of the tags is given, and one of the interesting challenges of this area is to provide an algorithm generating the ontology of the tags from the available data. In contrast, there are also other types of tagged networks available for research, where the tags are already organized into a directed acyclic graph (DAG), encapsulating the ‘is a sub-category of’ type of hierarchy between each other. In this paper, we study how this DAG affects the statistical distribution of tags on the nodes marked by the tags in various real networks. The motivation for this research was the fact that understanding the tagging based on a known hierarchy can help in revealing the hidden hierarchy of tags in collaborative tagging systems. We analyse the relation between the tag-frequency and the position of the tag in the DAG in two large sub-networks of the English Wikipedia and a protein-protein interaction network. We also study the tag co-occurrence statistics by introducing a two-dimensional (2D) tag-distance distribution preserving both the difference in the levels and the absolute distance in the DAG for the co-occurring pairs of tags. Our most interesting finding is that the local relevance of tags in the DAG (i.e. their rank or significance as characterized by, e.g., the length of the branches starting from them) is much more important than their global distance from the root. Furthermore, we also introduce a simple tagging model based on random walks on the DAG, capable of

Ontologies and tag-statistics

International Nuclear Information System (INIS)

Tibély, Gergely; Vicsek, Tamás; Pollner, Péter; Palla, Gergely

2012-01-01

Due to the increasing popularity of collaborative tagging systems, the research on tagged networks, hypergraphs, ontologies, folksonomies and other related concepts is becoming an important interdisciplinary area with great potential and relevance for practical applications. In most collaborative tagging systems the tagging by the users is completely ‘flat’, while in some cases they are allowed to define a shallow hierarchy for their own tags. However, usually no overall hierarchical organization of the tags is given, and one of the interesting challenges of this area is to provide an algorithm generating the ontology of the tags from the available data. In contrast, there are also other types of tagged networks available for research, where the tags are already organized into a directed acyclic graph (DAG), encapsulating the ‘is a sub-category of’ type of hierarchy between each other. In this paper, we study how this DAG affects the statistical distribution of tags on the nodes marked by the tags in various real networks. The motivation for this research was the fact that understanding the tagging based on a known hierarchy can help in revealing the hidden hierarchy of tags in collaborative tagging systems. We analyse the relation between the tag-frequency and the position of the tag in the DAG in two large sub-networks of the English Wikipedia and a protein-protein interaction network. We also study the tag co-occurrence statistics by introducing a two-dimensional (2D) tag-distance distribution preserving both the difference in the levels and the absolute distance in the DAG for the co-occurring pairs of tags. Our most interesting finding is that the local relevance of tags in the DAG (i.e. their rank or significance as characterized by, e.g., the length of the branches starting from them) is much more important than their global distance from the root. Furthermore, we also introduce a simple tagging model based on random walks on the DAG, capable of

77 FR 25131 - Turning Point Solar LLC: Notice of Finding of No Significant Impact

Science.gov (United States)

2012-04-27

... monocrystalline photovoltaic panels mounted on fixed solar racking equipment and the construction of access roads... DEPARTMENT OF AGRICULTURE Rural Utilities Service Turning Point Solar LLC: Notice of Finding of No... Environmental Assessment (EA) associated with a solar generation project. The EA was prepared in accordance with...

Statistical and extra-statistical considerations in differential item functioning analyses

Directory of Open Access Journals (Sweden)

G. K. Huysamen

2004-10-01

Full Text Available This article briefly describes the main procedures for performing differential item functioning (DIF analyses and points out some of the statistical and extra-statistical implications of these methods. Research findings on the sources of DIF, including those associated with translated tests, are reviewed. As DIF analyses are oblivious of correlations between a test and relevant criteria, the elimination of differentially functioning items does not necessarily improve predictive validity or reduce any predictive bias. The implications of the results of past DIF research for test development in the multilingual and multi-cultural South African society are considered. Opsomming Hierdie artikel beskryf kortliks die hoofprosedures vir die ontleding van differensiële itemfunksionering (DIF en verwys na sommige van die statistiese en buite-statistiese implikasies van hierdie metodes. ’n Oorsig word verskaf van navorsingsbevindings oor die bronne van DIF, insluitend dié by vertaalde toetse. Omdat DIF-ontledings nie die korrelasies tussen ’n toets en relevante kriteria in ag neem nie, sal die verwydering van differensieel-funksionerende items nie noodwendig voorspellingsgeldigheid verbeter of voorspellingsydigheid verminder nie. Die implikasies van vorige DIF-navorsingsbevindings vir toetsontwikkeling in die veeltalige en multikulturele Suid-Afrikaanse gemeenskap word oorweeg.

Intraductal papillary mucinous neoplasms of the pancreas: Correlation of helical CT features with pathologic findings

International Nuclear Information System (INIS)

Liu Yu; Lin Xiaozhu; Upadhyaya, Manavendra; Song Qi; Chen Kemin

2010-01-01

Objective: To evaluate the CT features of intraductal papillary mucinous neoplasms of the pancreas (IPMNs), and to compare with pathological findings in order to identify CT features that can be helpful in differentiating benign IPMNs from malignant IPMNs. Materials and methods: The CT findings in 25 patients were reviewed for tumor location, tumor type, dilatation of the main pancreatic duct (MPD), MPD involvement, mural node or solid attenuating component, tumor size in branch duct or mixed duct type, dilatation of common bile duct (CBD) and invasion of surrounding structures. The data was subjected to Chi-Square Tests or Fisher's Exact Test using SPSS13.0 software with p value < 0.05 indicating significant statistical difference. Results: Presence of mural node or solid enhancing component, size of mural node or solid enhancing component ≥7 mm, dilatation of CBD was more common in malignant IPMNs (p < 0.05). None of tumor location, tumor type, dilatation of MPD, MPD involvement, tumor size, and invasion of surrounding structures was statistically significant in differentiating benign from malignant IPMNs. Conclusions: CT features suggestive of malignant or invasive IPMNs include presence of mural node or solid enhancing component, size of mural node or solid enhancing component ≥7 mm, and dilatation of CBD.

A statistical method for testing epidemiological results, as applied to the Hanford worker population

International Nuclear Information System (INIS)

Brodsky, A.

1979-01-01

Some recent reports of Mancuso, Stewart and Kneale claim findings of radiation-produced cancer in the Hanford worker population. These claims are based on statistical computations that use small differences in accumulated exposures between groups dying of cancer and groups dying of other causes; actual mortality and longevity were not reported. This paper presents a statistical method for evaluation of actual mortality and longevity longitudinally over time, as applied in a primary analysis of the mortality experience of the Hanford worker population. Although available, this method was not utilized in the Mancuso-Stewart-Kneale paper. The author's preliminary longitudinal analysis shows that the gross mortality experience of persons employed at Hanford during 1943-70 interval did not differ significantly from that of certain controls, when both employees and controls were selected from families with two or more offspring and comparison were matched by age, sex, race and year of entry into employment. This result is consistent with findings reported by Sanders (Health Phys. vol.35, 521-538, 1978). The method utilizes an approximate chi-square (1 D.F.) statistic for testing population subgroup comparisons, as well as the cumulation of chi-squares (1 D.F.) for testing the overall result of a particular type of comparison. The method is available for computer testing of the Hanford mortality data, and could also be adapted to morbidity or other population studies. (author)

Dynamics of EEG functional connectivity during statistical learning.

Science.gov (United States)

Tóth, Brigitta; Janacsek, Karolina; Takács, Ádám; Kóbor, Andrea; Zavecz, Zsófia; Nemeth, Dezso

2017-10-01

Statistical learning is a fundamental mechanism of the brain, which extracts and represents regularities of our environment. Statistical learning is crucial in predictive processing, and in the acquisition of perceptual, motor, cognitive, and social skills. Although previous studies have revealed competitive neurocognitive processes underlying statistical learning, the neural communication of the related brain regions (functional connectivity, FC) has not yet been investigated. The present study aimed to fill this gap by investigating FC networks that promote statistical learning in humans. Young adults (N=28) performed a statistical learning task while 128-channels EEG was acquired. The task involved probabilistic sequences, which enabled to measure incidental/implicit learning of conditional probabilities. Phase synchronization in seven frequency bands was used to quantify FC between cortical regions during the first, second, and third periods of the learning task, respectively. Here we show that statistical learning is negatively correlated with FC of the anterior brain regions in slow (theta) and fast (beta) oscillations. These negative correlations increased as the learning progressed. Our findings provide evidence that dynamic antagonist brain networks serve a hallmark of statistical learning. Copyright © 2017 Elsevier Inc. All rights reserved.

Research cardiac magnetic resonance imaging in end stage renal disease - incidence, significance and implications of unexpected incidental findings

Energy Technology Data Exchange (ETDEWEB)

Rutherford, Elaine; Weir-McCall, Jonathan R.; Houston, J.G.; Struthers, Allan D. [Ninewells Hospital, Division of Cardiovascular and Diabetes Medicine, Dundee (United Kingdom); Patel, Rajan K.; Jardine, Alan G.; Mark, Patrick B. [Institute of Cardiovascular and Medical Sciences, Glasgow (United Kingdom); Roditi, Giles [NHS Greater Glasgow and Clyde, Department of Radiology, Glasgow Royal Infirmary, Glasgow (United Kingdom)

2017-01-15

Left ventricular mass (LVM) at cardiac magnetic resonance imaging (CMR) is a frequent end point in clinical trials in nephrology. Trial participants with end stage renal disease (ESRD) may have a greater frequency of incidental findings (IF). We retrospectively investigated prevalence of IF in previous research CMR and reviewed their subsequent impact on participants. Between 2002 and 2006, 161 ESRD patients underwent CMR in a transplant assessment study. Images were used to assess LV mass and function. In the current study a radiologist reviewed the scans for IF. Review of patient records determined the subsequent clinical significance of IF. There were 150 IF in 95 study participants. Eighty-four (56 %) were new diagnoses. One hundred and two were non-cardiac. Fifteen were suspicious of malignancy. There was a clinically significant IF for 14.9 % of the participants. In six cases earlier identification of an IF may have improved quality of life or survival. Without radiology support clinically important IF may be missed on CMR. Patients undergoing CMR in trials should be counselled about the frequency and implications of IF. Patients with ESRD have a higher prevalence of IF than reported in other populations. Nephrology studies require mechanisms for radiologist reporting and strategies for dealing with IF. (orig.)

Comparison of Chest X-Ray Findings of Smear Positive and Smear Negative Patients with Pulmonary Tuberculosis

International Nuclear Information System (INIS)

Ebrahimzadeh, Azadeh; Mohammadifard, Mahyar; Naseh, Godratallah

2014-01-01

Tuberculosis is a chronic pulmonary infectious disease that has affected one-third of the people in the world. It causes nine million new cases and two million deaths per year. Chest radiography associated with Ziehl-Neelsen acid-fast staining procedure significantly helps the diagnosis of pulmonary tuberculosis (PTB). Chest radiography can help the diagnosis of tuberculosis in patients with a negative smear sample result that is mainly diagnosed with delay. In this study, chest X-ray findings of PTB were compared in two groups of smear positive and smear negative patients. In this retrospective descriptive-analytical study, 376 patients who had been confirmed with PTB were referred to Birjand Health Care Center from 2001 to 2006. Out of the 376 patients, 100 patients with a positive smear based on WHO criteria were selected. In addition, among negative smear patients, 100 were selected in whom similar demographic characteristics with positive smear patients were seen. All of them had undergone chest radiographies that were then interpreted by two expert radiologists independently. Moreover, all patients’ sputa were examined by an expert laboratory technician at the reference laboratory of the health center. The obtained data were analyzed by means of frequency distribution table and descriptive statistics using SPSS (version 15) and Chi-square statistical test. Except reticulo-nodular infiltration, the relative frequency of other radiographic findings in positive smear patients were more than negative smear patients; and only differences in calcification variables, mediastinal widening, patchy infiltration and hilar adenopathy were statistically significant (P < 0.05). Based on the results of this study, although radiographic findings are not diagnostic in PTB, they are helpful if the assessment associates with the view of clinical manifestations and sputum smears

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

A radiologic analysis of hysterosalpinggographic finding in infertility

International Nuclear Information System (INIS)

Choi, Hae Young; Lee, Kyung Ja; Yoo, Seong Yul; Kim, Hee Seup

1985-01-01

Hysterosalpingography has been universally accepted and approved as valuable aid in the diagnosis and treatment of infertility. Radiologic and clinical analysis had been made on 200 cases of known infertile patient in Ewha Womans University Hospital from January, 1976 to August, 1979. The results are as followings: 1. In 200 cases of infertility, 90 cases (45.5%) are primary infertility and remaining 110 cases (55.5%) are secondary infertility. 2. The peak number of age distribution is 2nd decade group in 115 cases (57.5%). 3. The peak number of duration of infertility is less than 3 years in 107 cases (53,5%). 4. Abnormal uterine finding is 25 cases (12.5%) and there 4 cases (2.0%) of congenital anomaly among them. 5. Abnormal tubal finding is 120 cases (60.0%) and there are 84 cases (42.0%) of without spillage, 36 cases (18.0%) of with spillage, 51 cases (25.5%) of hydrosalpinx, 49 cases (24.5%) of simple obstruction among them. 6. Intravasation is noted in 66 cases (33.3%) among 200 cases. 7. There are significant results between the past history and the hysterosalpiingographic findings by the statistical approach. 8. Pregnancy after hysterosalpingography is noted in 16 cases (8.0%) among 200 cases.

Infants generalize representations of statistically segmented words

Directory of Open Access Journals (Sweden)

Katharine eGraf Estes

2012-10-01

Full Text Available The acoustic variation in language presents learners with a substantial challenge. To learn by tracking statistical regularities in speech, infants must recognize words across tokens that differ based on characteristics such as the speaker’s voice, affect, or the sentence context. Previous statistical learning studies have not investigated how these types of surface form variation affect learning. The present experiments used tasks tailored to two distinct developmental levels to investigate the robustness of statistical learning to variation. Experiment 1 examined statistical word segmentation in 11-month-olds and found that infants can recognize statistically segmented words across a change in the speaker’s voice from segmentation to testing. The direction of infants’ preferences suggests that recognizing words across a voice change is more difficult than recognizing them in a consistent voice. Experiment 2 tested whether 17-month-olds can generalize the output of statistical learning across variation to support word learning. The infants were successful in their generalization; they associated referents with statistically defined words despite a change in voice from segmentation to label learning. Infants’ learning patterns also indicate that they formed representations of across-word syllable sequences during segmentation. Thus, low probability sequences can act as object labels in some conditions. The findings of these experiments suggest that the units that emerge during statistical learning are not perceptually constrained, but rather are robust to naturalistic acoustic variation.

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.

Statistics for Learning Genetics

Science.gov (United States)

Charles, Abigail Sheena

This study investigated the knowledge and skills that biology students may need to help them understand statistics/mathematics as it applies to genetics. The data are based on analyses of current representative genetics texts, practicing genetics professors' perspectives, and more directly, students' perceptions of, and performance in, doing statistically-based genetics problems. This issue is at the emerging edge of modern college-level genetics instruction, and this study attempts to identify key theoretical components for creating a specialized biological statistics curriculum. The goal of this curriculum will be to prepare biology students with the skills for assimilating quantitatively-based genetic processes, increasingly at the forefront of modern genetics. To fulfill this, two college level classes at two universities were surveyed. One university was located in the northeastern US and the other in the West Indies. There was a sample size of 42 students and a supplementary interview was administered to a select 9 students. Interviews were also administered to professors in the field in order to gain insight into the teaching of statistics in genetics. Key findings indicated that students had very little to no background in statistics (55%). Although students did perform well on exams with 60% of the population receiving an A or B grade, 77% of them did not offer good explanations on a probability question associated with the normal distribution provided in the survey. The scope and presentation of the applicable statistics/mathematics in some of the most used textbooks in genetics teaching, as well as genetics syllabi used by instructors do not help the issue. It was found that the text books, often times, either did not give effective explanations for students, or completely left out certain topics. The omission of certain statistical/mathematical oriented topics was seen to be also true with the genetics syllabi reviewed for this study. Nonetheless

Interrater and intrarater agreements of magnetic resonance imaging findings in the lumbar spine: significant variability across degenerative conditions.

Science.gov (United States)

Fu, Michael C; Buerba, Rafael A; Long, William D; Blizzard, Daniel J; Lischuk, Andrew W; Haims, Andrew H; Grauer, Jonathan N

2014-10-01

Magnetic resonance imaging (MRI) is frequently used in the evaluation of degenerative conditions in the lumbar spine. The relative interrater and intrarater agreements of MRI findings across different pathologic conditions are underexplored, as most studies are focused on specific findings. The purpose of this study was to characterize the interrater and intrarater agreements of MRI findings used to assess the degenerative lumbar spine. A retrospective diagnostic study at a large academic medical center was undertaken with a panel of orthopedic surgeons and musculoskeletal radiologists to assess lumbar MRIs using standardized criteria. Seventy-five subjects who underwent routine lumbar spine MRI at our institution were included. Each MRI study was assessed for 10 lumbar degenerative findings using standardized criteria. Lumbar vertebral levels were assessed independently, where applicable, for a total of 52 data points collected per study. T2-weighted axial and sagittal MRI sequences were presented in random order to the four reviewers (two orthopedic spine surgeons and two musculoskeletal radiologists) independently to determine interrater agreement. The first 10 studies were reevaluated at the end to determine intrarater agreement. Images were assessed using standardized and pilot-tested criteria to assess disc degeneration, stenosis, and other degenerative changes. Interrater and intrarater absolute percent agreements were calculated. To highlight the most clinically important MRI disagreements, a modified agreement analysis was also performed (in which disagreements between the lowest two severity grades for applicable conditions were ignored). Fleiss kappa coefficients for interrater agreement were determined. The overall absolute and modified interrater agreements were 76.9% and 93.5%, respectively. The absolute and modified intrarater agreements were 81.3% and 92.7%, respectively. Average Fleiss kappa coefficient was 0.431, suggesting moderate overall

Prevalence of mucocutaneous findings in Celiac disease patients

Directory of Open Access Journals (Sweden)

Derya Yayla

2015-12-01

Full Text Available Background and Design: Celiac disease is an immune-mediated enteropathy which develops as a result of exposure to gluten in food products in individuals with a genetic predisposition. Gastrointestinal and extra-gastrointestinal clinical findings can be seen in these patients. An increased frequence of autoimmune diseases has been reported in patients with celiac disease. Some dermatological diseases, such as dermatitis herpetiformis, vitiligo, psoriasis, alopecia areata and recurrent aphthous stomatitis have been reported to be more common among patients with celiac disease. However, there are no controlled studies on this subject. The aim of this study was to identify the mucocutaneous symptoms seen in celiac patients and to compare these findings with a control group. Materials and Methods: Forty-nine celiac patients and 54 age-and sex-matched healthy volunteers were included in the study. In the patient group, celiac disease history, height and weight parameters, the medications of the patients, compliance to a gluten-free diet, concomitant skin disorders and additional illnesses were questioned; height and weight parameters, diagnosed illnesses, and medications were questioned in the control group. Dermatological analyses were performed in all participants. Results: Mucocutaneous findings were found to be present in 38 patients (77.6% in the celiac patient group and in 31 (57.4% individuals in the control group. The presence of mucocutaneous findings in celiac patients was significantly more common than in the control group. While immune-mediated mucocutaneous diseases were detected in 8 celiac patients (16.3%, none of the individuals in the control group had immune-mediated mucocutaneous diseases and a statistically significant difference was found between the two groups. Conclusion: In celiac patients, the frequency of immune-mediated mucocutaneous diseases and all mucocutaneous diseases were found to be increased. Therefore, we suggest

Mycoplasma hominis: an incidental but significant finding by routine bacteriological culture

DEFF Research Database (Denmark)

Gertsen, Jan Berg; Schønheyder, Henrik Carl

2009-01-01

Objectives: M. hominis is part of the normal mucosal flora and is primarily associated with infections in the genitourinary tract. Most infections occur following delivery or genitourinary instrumentation, but are also seen in immunocompromised patients. We present 4 cases diagnosed by routine ba...... Serum Institut, Copenhagen (by courtesy to Jørgen Skov). Results: The four patients were immunocompetent women (23-56 years of age) without significant comorbidity (Table). In all patients M. hominis were obtained in pure culture. At the time of diagnosis three patients had abscesses...

A Framework for Assessing High School Students' Statistical Reasoning.

Science.gov (United States)

Chan, Shiau Wei; Ismail, Zaleha; Sumintono, Bambang

2016-01-01

Based on a synthesis of literature, earlier studies, analyses and observations on high school students, this study developed an initial framework for assessing students' statistical reasoning about descriptive statistics. Framework descriptors were established across five levels of statistical reasoning and four key constructs. The former consisted of idiosyncratic reasoning, verbal reasoning, transitional reasoning, procedural reasoning, and integrated process reasoning. The latter include describing data, organizing and reducing data, representing data, and analyzing and interpreting data. In contrast to earlier studies, this initial framework formulated a complete and coherent statistical reasoning framework. A statistical reasoning assessment tool was then constructed from this initial framework. The tool was administered to 10 tenth-grade students in a task-based interview. The initial framework was refined, and the statistical reasoning assessment tool was revised. The ten students then participated in the second task-based interview, and the data obtained were used to validate the framework. The findings showed that the students' statistical reasoning levels were consistent across the four constructs, and this result confirmed the framework's cohesion. Developed to contribute to statistics education, this newly developed statistical reasoning framework provides a guide for planning learning goals and designing instruction and assessments.

Ultrasonographic findings of lateral epicondylitis of humerus

Energy Technology Data Exchange (ETDEWEB)

Choi, Joon Hyuk; Ha, Doo Heo [Pundang CHA Univ., Seongnam (Korea, Republic of)

2002-03-01

To evaluate the ultrasonographic findings of lateral epicondylitis and their relationship with clinical outcome. The findings of ultrasonographic examinations of eighteen elbow joints in 15 patients (M:F=5:10; age:38-65(mean, 47.6) years) with lateral epicondylitis were reviewed. Two patients underwent surgery, two were not treated, and the remaining 11 were treated conservatively. Symptomatic improvement was noted 1 week after conservative treatment in two cases, at 2 weeks in five cases, at 3 weeks in three cases, and at 5 weeks in one case. With patients in the 90 degree flexed elbow position and in a supinated wrist, weexamined the extensor carpi radialis brevis (ECRB) tendon around the lateral epicondyle using ultrasound equipment with a 7-11 MHz linear transducer. The findings were assessed in terms of swelling of the tendon, changes in its echotexture, the presence of calcification of cystic degeneration, loss of the hypoechoic band between the tendon and bony cortex of the lateral epicondyle, cortical irregularity of the lateral epicondyle, and fluid collection around the tendon. Any relationships between each ultrasonographic finding and the treatment interval after which symptomatic improvement was noted were evaluated. In the 18 joints, change was heterogeneous hypoechogenicity in 13, and heterogeneous mixed echogenicity in three. Other ultrasonographic findings were swelling of the tendon in ten cases, loss of the hypoechoic band in 14, cortical irregularity in five, calcification in four, cystic degeneration in nine, and fluid collection around the tendon in four. In patients treated conservatively, there was no statistically significant difference between each ultrasonographic finding and the treatment interval after which symptomatic improvement was noted. Ultrasonography can be used to assess changes in the ECRB tendon and lateral epicondyle occurring in lateral epicondylitis, but fails to provide information on the rapidity of symptomatic

Ultrasonographic findings of lateral epicondylitis of humerus

International Nuclear Information System (INIS)

Choi, Joon Hyuk; Ha, Doo Heo

2002-01-01

To evaluate the ultrasonographic findings of lateral epicondylitis and their relationship with clinical outcome. The findings of ultrasonographic examinations of eighteen elbow joints in 15 patients (M:F=5:10; age:38-65(mean, 47.6) years) with lateral epicondylitis were reviewed. Two patients underwent surgery, two were not treated, and the remaining 11 were treated conservatively. Symptomatic improvement was noted 1 week after conservative treatment in two cases, at 2 weeks in five cases, at 3 weeks in three cases, and at 5 weeks in one case. With patients in the 90 degree flexed elbow position and in a supinated wrist, weexamined the extensor carpi radialis brevis (ECRB) tendon around the lateral epicondyle using ultrasound equipment with a 7-11 MHz linear transducer. The findings were assessed in terms of swelling of the tendon, changes in its echotexture, the presence of calcification of cystic degeneration, loss of the hypoechoic band between the tendon and bony cortex of the lateral epicondyle, cortical irregularity of the lateral epicondyle, and fluid collection around the tendon. Any relationships between each ultrasonographic finding and the treatment interval after which symptomatic improvement was noted were evaluated. In the 18 joints, change was heterogeneous hypoechogenicity in 13, and heterogeneous mixed echogenicity in three. Other ultrasonographic findings were swelling of the tendon in ten cases, loss of the hypoechoic band in 14, cortical irregularity in five, calcification in four, cystic degeneration in nine, and fluid collection around the tendon in four. In patients treated conservatively, there was no statistically significant difference between each ultrasonographic finding and the treatment interval after which symptomatic improvement was noted. Ultrasonography can be used to assess changes in the ECRB tendon and lateral epicondyle occurring in lateral epicondylitis, but fails to provide information on the rapidity of symptomatic

Statistical Engineering in Air Traffic Management Research

Science.gov (United States)

Wilson, Sara R.

2015-01-01

NASA is working to develop an integrated set of advanced technologies to enable efficient arrival operations in high-density terminal airspace for the Next Generation Air Transportation System. This integrated arrival solution is being validated and verified in laboratories and transitioned to a field prototype for an operational demonstration at a major U.S. airport. Within NASA, this is a collaborative effort between Ames and Langley Research Centers involving a multi-year iterative experimentation process. Designing and analyzing a series of sequential batch computer simulations and human-in-the-loop experiments across multiple facilities and simulation environments involves a number of statistical challenges. Experiments conducted in separate laboratories typically have different limitations and constraints, and can take different approaches with respect to the fundamental principles of statistical design of experiments. This often makes it difficult to compare results from multiple experiments and incorporate findings into the next experiment in the series. A statistical engineering approach is being employed within this project to support risk-informed decision making and maximize the knowledge gained within the available resources. This presentation describes a statistical engineering case study from NASA, highlights statistical challenges, and discusses areas where existing statistical methodology is adapted and extended.

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

Science.gov (United States)

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.

Statistical properties of cross-correlation in the Korean stock market

Science.gov (United States)

Oh, G.; Eom, C.; Wang, F.; Jung, W.-S.; Stanley, H. E.; Kim, S.

2011-01-01

We investigate the statistical properties of the cross-correlation matrix between individual stocks traded in the Korean stock market using the random matrix theory (RMT) and observe how these affect the portfolio weights in the Markowitz portfolio theory. We find that the distribution of the cross-correlation matrix is positively skewed and changes over time. We find that the eigenvalue distribution of original cross-correlation matrix deviates from the eigenvalues predicted by the RMT, and the largest eigenvalue is 52 times larger than the maximum value among the eigenvalues predicted by the RMT. The β_{473} coefficient, which reflect the largest eigenvalue property, is 0.8, while one of the eigenvalues in the RMT is approximately zero. Notably, we show that the entropy function E(σ) with the portfolio risk σ for the original and filtered cross-correlation matrices are consistent with a power-law function, E( σ) σ^{-γ}, with the exponent γ 2.92 and those for Asian currency crisis decreases significantly.

A statistical procedure for the qualification of indoor dust

International Nuclear Information System (INIS)

Scapin, Valdirene O.; Scapin, Marcos A.; Ribeiro, Andreza P.; Sato, Ivone M.

2009-01-01

The materials science advance has contributed to the humanity. Notwithstanding, serious environmental and human health problems are often observed. Thereby, many worldwide researchers have focused their work to diagnose, assess and monitor several environmental systems. In this work, a statistical procedure (on a 0.05 significance level) that allows verifying if indoor dust samples have characteristics of soil/sediment is presented. Dust samples were collected from 69 residences using a domestic vacuum cleaner in four neighborhoods of the Sao Paulo metropolitan region, Brazil, between 2006 and 2008. The samples were sieved in the fractions of 150-75 (C), 75-63 (M) and <63 μm (F). The elemental concentrations were determined by X-ray fluorescence (WDXRF). Afterwards, the indoor samples results (group A) were compared to the group of 109 certificated reference materials, which included different kinds of geological matrices, such as clay, sediment, sand and sludge (group B) and to the continental crust values (group C). Initially, the Al/Si ratio was calculated for the groups (A, B, C). The variance analysis (ANOVA), followed by Tukey test, was used to find out if there was a significant difference between the concentration means of the considered groups. According to the statistical tests; the group B presented results that are considered different from others. The interquartile range (IQR) was used to detected outlier values. ANOVA was applied again and the results (p ≥ 0.05) showed equality between ratios means of the three groups. Accordingly, the results suggest that the indoor dust samples have characteristic of soil/sediment. The statistical procedure may be used as a tool to clear the information about contaminants in dust samples, since they have characteristic of soil and may be compared with values reported by environmental control organisms. (author)

Statistical Signal Process in R Language in the Pharmacovigilance Programme of India.

Science.gov (United States)

Kumar, Aman; Ahuja, Jitin; Shrivastava, Tarani Prakash; Kumar, Vipin; Kalaiselvan, Vivekanandan

2018-05-01

The Ministry of Health & Family Welfare, Government of India, initiated the Pharmacovigilance Programme of India (PvPI) in July 2010. The purpose of the PvPI is to collect data on adverse reactions due to medications, analyze it, and use the reference to recommend informed regulatory intervention, besides communicating the risk to health care professionals and the public. The goal of the present study was to apply statistical tools to find the relationship between drugs and ADRs for signal detection by R programming. Four statistical parameters were proposed for quantitative signal detection. These 4 parameters are IC 025 , PRR and PRR lb , chi-square, and N 11 ; we calculated these 4 values using R programming. We analyzed 78,983 drug-ADR combinations, and the total count of drug-ADR combination was 4,20,060. During the calculation of the statistical parameter, we use 3 variables: (1) N 11 (number of counts), (2) N 1. (Drug margin), and (3) N .1 (ADR margin). The structure and calculation of these 4 statistical parameters in R language are easily understandable. On the basis of the IC value (IC value >0), out of the 78,983 drug-ADR combination (drug-ADR combination), we found the 8,667 combinations to be significantly associated. The calculation of statistical parameters in R language is time saving and allows to easily identify new signals in the Indian ICSR (Individual Case Safety Reports) database.

Finding the Best Feature Detector-Descriptor Combination

DEFF Research Database (Denmark)

Dahl, Anders Lindbjerg; Aanæs, Henrik; Pedersen, Kim Steenstrup

2011-01-01

, not statistically significantly better than some other methods. As a byproduct of this investigation, we have also tested various DAISY type descriptors, and found that the difference among their performance is statistically insignificant using this dataset. Furthermore, we have not been able to produce results...

Advanced Placement® Statistics Students' Education Choices after High School. Research Notes. RN-38

Science.gov (United States)

Patterson, Brian F.

2009-01-01

Taking the AP Statistics course and exam does not appear to be related to greater interest in the statistical sciences. Despite this finding, with respect to deciding whether to take further statistics course work and majoring in statistics, students appear to feel prepared for, but not interested in, further study. There is certainly more…

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

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.

Bone marrow edema pattern in advanced hip osteoarthritis: quantitative assessment with magnetic resonance imaging and correlation with clinical examination, radiographic findings, and histopathology

International Nuclear Information System (INIS)

Taljanovic, Mihra S.; Schwartz, Stephanie A.; Graham, Anna R.; Benjamin, James B.; Gmitro, Arthur F.; Krupinski, Elizabeth A.; Hunter, Tim B.; Resnick, Donald L.

2008-01-01

To correlate the amount of bone marrow edema (BME) calculated by magnetic resonance imaging(MRI) with clinical findings, histopathology, and radiographic findings, in patients with advanced hip osteoarthritis(OA). The study was approved by The Institutional Human Subject Protection Committee. Coronal MRI of hips was acquired in 19 patients who underwent hip replacement. A spin echo (SE) sequence with four echoes and separate fast spin echo (FSE) proton density (PD)-weighted SE sequences of fat (F) and water (W) were acquired with water and fat suppression, respectively. T2 and water:fat ratio calculations were made for the outlined regions of interest. The calculated MRI values were correlated with the clinical, radiographic, and histopathologic findings. Analyses of variance were done on the MRI data for W/(W + F) and for T2 values (total and focal values) for the symptomatic and contralateral hips. The values were significantly higher in the study group. Statistically significant correlations were found between pain and total W/(W + F), pain and focal T2 values, and the number of microfractures and calculated BME for the focal W/(W + F) in the proximal femora. Statistically significant correlations were found between the radiographic findings and MRI values for total W/(W + F), focal W/(W + F) and focal T2 and among the radiographic findings, pain, and hip movement. On histopathology, only a small amount of BME was seen in eight proximal femora. The amount of BME in the OA hip, as measured by MRI, correlates with the severity of pain, radiographic findings, and number of microfractures. (orig.)

Testing statistical hypotheses of equivalence

CERN Document Server

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

Inferential Statistics from Black Hispanic Breast Cancer Survival Data

Directory of Open Access Journals (Sweden)

Hafiz M. R. Khan

2014-01-01

Full Text Available In this paper we test the statistical probability models for breast cancer survival data for race and ethnicity. Data was collected from breast cancer patients diagnosed in United States during the years 1973–2009. We selected a stratified random sample of Black Hispanic female patients from the Surveillance Epidemiology and End Results (SEER database to derive the statistical probability models. We used three common model building criteria which include Akaike Information Criteria (AIC, Bayesian Information Criteria (BIC, and Deviance Information Criteria (DIC to measure the goodness of fit tests and it was found that Black Hispanic female patients survival data better fit the exponentiated exponential probability model. A novel Bayesian method was used to derive the posterior density function for the model parameters as well as to derive the predictive inference for future response. We specifically focused on Black Hispanic race. Markov Chain Monte Carlo (MCMC method was used for obtaining the summary results of posterior parameters. Additionally, we reported predictive intervals for future survival times. These findings would be of great significance in treatment planning and healthcare resource allocation.

Common misconceptions about data analysis and statistics1

Science.gov (United States)

Motulsky, Harvey J

2015-01-01

Ideally, any experienced investigator with the right tools should be able to reproduce a finding published in a peer-reviewed biomedical science journal. In fact, the reproducibility of a large percentage of published findings has been questioned. Undoubtedly, there are many reasons for this, but one reason may be that investigators fool themselves due to a poor understanding of statistical concepts. In particular, investigators often make these mistakes: (1) P-Hacking. This is when you reanalyze a data set in many different ways, or perhaps reanalyze with additional replicates, until you get the result you want. (2) Overemphasis on P values rather than on the actual size of the observed effect. (3) Overuse of statistical hypothesis testing, and being seduced by the word “significant”. (4) Overreliance on standard errors, which are often misunderstood. PMID:25692012

Students' Perspectives of Using Cooperative Learning in a Flipped Statistics Classroom

Science.gov (United States)

Chen, Liwen; Chen, Tung-Liang; Chen, Nian-Shing

2015-01-01

Statistics has been recognised as one of the most anxiety-provoking subjects to learn in the higher education context. Educators have continuously endeavoured to find ways to integrate digital technologies and innovative pedagogies in the classroom to eliminate the fear of statistics. The purpose of this study is to systematically identify…

Where did Venomous Snakes Strike? A Spatial Statistical Analysis of Snakebite Cases in Bondowoso Regency, Indonesia

Directory of Open Access Journals (Sweden)

Farid Rifaie

2017-07-01

Full Text Available Snakebite envenomation in Indonesia is a health burden that receives no attention from stakeholders. The high mortality and morbidity rate caused by snakebite in Indonesia is estimated from regional reports. The true burden of this issue in Indonesia needs to be revealed even starting from a small part of the country. Medical records from a Hospital in Bondowoso Regency were the data source of the snakebite cases. Three spatial statistical summaries were applied to analyze the spatial pattern of snakebite incidents. The comparison between statistical functions and the theoretical model of random distributions shows a significant clustering pattern of the events. The pattern indicates that five subdistricts in Bondowoso have a substantial number of snakebite cases more than other regions. This finding shows the potential application of spatial statistics for the snakebite combating strategy in this area by identifying the priority locations of the snakebite cases.

Statistical Dependence of Pipe Breaks on Explanatory Variables

Directory of Open Access Journals (Sweden)

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.

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 physics of an anyon gas

International Nuclear Information System (INIS)

Dasnieres de Veigy, A.

1994-01-01

In quantum two-dimensional physics, anyons are particles which have an intermediate statistics between Bose-Einstein and Fermi-Dirac statistics. The wave amplitude can change by an arbitrary phase under particle exchanges. Contrary to bosons or fermions, the permutation group cannot uniquely characterize this phase and one must introduce the braid group. One shows that the statistical ''interaction'' is equivalent to an Aharonov-Bohm interaction which derives from a Chern-Simons lagrangian. The main subject of this thesis is the thermodynamics of an anyon gas. Since the complete spectrum of N anyons seems out of reach, we have done a perturbative computation of the equation of state at second order near Bose or Fermi statistics. One avoids ultraviolet divergences by noticing that the short-range singularities of the statistical interaction enforce the wave functions to vanish when two particles approach each other (statistical exclusion). The gas is confined in a harmonic well in order to obtain the thermodynamics limit when the harmonic attraction goes to zero. Infrared divergences thus cancel in this limit and a finite virial expansion is obtained. The complexity of the anyon model appears in this result. We have also computed the equation of state of an anyon gas in a magnetic field strong enough to project the system in its degenerate groundstate. This result concerns anyons with any statistics. One then finds an exclusion principle generalizing the Pauli principle to anyons. On the other hand, we have defined a model of two-dimensional particles topologically interacting at a distance. The anyon model is recovered as a particular case where all particles are identical. (orig.)

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

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.

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.

A rank-based algorithm of differential expression analysis for small cell line data with statistical control.

Science.gov (United States)

Li, Xiangyu; Cai, Hao; Wang, Xianlong; Ao, Lu; Guo, You; He, Jun; Gu, Yunyan; Qi, Lishuang; Guan, Qingzhou; Lin, Xu; Guo, Zheng

2017-10-13

To detect differentially expressed genes (DEGs) in small-scale cell line experiments, usually with only two or three technical replicates for each state, the commonly used statistical methods such as significance analysis of microarrays (SAM), limma and RankProd (RP) lack statistical power, while the fold change method lacks any statistical control. In this study, we demonstrated that the within-sample relative expression orderings (REOs) of gene pairs were highly stable among technical replicates of a cell line but often widely disrupted after certain treatments such like gene knockdown, gene transfection and drug treatment. Based on this finding, we customized the RankComp algorithm, previously designed for individualized differential expression analysis through REO comparison, to identify DEGs with certain statistical control for small-scale cell line data. In both simulated and real data, the new algorithm, named CellComp, exhibited high precision with much higher sensitivity than the original RankComp, SAM, limma and RP methods. Therefore, CellComp provides an efficient tool for analyzing small-scale cell line data. © The Author 2017. Published by Oxford University Press.

A statistical investigation of the mass discrepancy-acceleration relation

Science.gov (United States)

Desmond, Harry

2017-02-01

We use the mass discrepancy-acceleration relation (the correlation between the ratio of total-to-visible mass and acceleration in galaxies; MDAR) to test the galaxy-halo connection. We analyse the MDAR using a set of 16 statistics that quantify its four most important features: shape, scatter, the presence of a `characteristic acceleration scale', and the correlation of its residuals with other galaxy properties. We construct an empirical framework for the galaxy-halo connection in LCDM to generate predictions for these statistics, starting with conventional correlations (halo abundance matching; AM) and introducing more where required. Comparing to the SPARC data, we find that: (1) the approximate shape of the MDAR is readily reproduced by AM, and there is no evidence that the acceleration at which dark matter becomes negligible has less spread in the data than in AM mocks; (2) even under conservative assumptions, AM significantly overpredicts the scatter in the relation and its normalization at low acceleration, and furthermore positions dark matter too close to galaxies' centres on average; (3) the MDAR affords 2σ evidence for an anticorrelation of galaxy size and Hubble type with halo mass or concentration at fixed stellar mass. Our analysis lays the groundwork for a bottom-up determination of the galaxy-halo connection from relations such as the MDAR, provides concrete statistical tests for specific galaxy formation models, and brings into sharper focus the relative evidence accorded by galaxy kinematics to LCDM and modified gravity alternatives.

Beyond δ : Tailoring marked statistics to reveal modified gravity

Science.gov (United States)

Valogiannis, Georgios; Bean, Rachel

2018-01-01

Models that seek to explain cosmic acceleration through modifications to general relativity (GR) evade stringent Solar System constraints through a restoring, screening mechanism. Down-weighting the high-density, screened regions in favor of the low density, unscreened ones offers the potential to enhance the amount of information carried in such modified gravity models. In this work, we assess the performance of a new "marked" transformation and perform a systematic comparison with the clipping and logarithmic transformations, in the context of Λ CDM and the symmetron and f (R ) modified gravity models. Performance is measured in terms of the fractional boost in the Fisher information and the signal-to-noise ratio (SNR) for these models relative to the statistics derived from the standard density distribution. We find that all three statistics provide improved Fisher boosts over the basic density statistics. The model parameters for the marked and clipped transformation that best enhance signals and the Fisher boosts are determined. We also show that the mark is useful both as a Fourier and real-space transformation; a marked correlation function also enhances the SNR relative to the standard correlation function, and can on mildly nonlinear scales show a significant difference between the Λ CDM and the modified gravity models. Our results demonstrate how a series of simple analytical transformations could dramatically increase the predicted information extracted on deviations from GR, from large-scale surveys, and give the prospect for a much more feasible potential detection.

CT findings of cerebral palsy and behaviour development

International Nuclear Information System (INIS)

Sakamoto, Zenji

1987-01-01

It is well recognized that CT scan is very useful in the early diagnosis of cerebral palsy. The author has studied this time the CT scan findings of cerebral palsy children in their relations to the type of palsy, cause of palsy, complications in the central nervous system, and prognosis of behaviour development, in order to predict the prognosis of behaviour development. Dilatation of the contralateral cerebral ventricle was found in 82 % of hemiplegic type. Abnormal EEG was found in 73 %, but their behaviour development was satisfactory, with good development of speech regardless to the side of palsy. This might be helped by compensational function of the brain due to plasticity. Diplegia presented bilateral moderate dilatation of ventricles with favorable prognosis. Tetraplegia was caused mostly by asphyxia or congenital anomaly and revealed marked dilatation of ventricles or severe cortical atrophy. Some cases presented diffuse cortical low-density, often associated with abnormal EEG, and their prognosis was worst. Athetosis had normal CT finding or mild ventricular dilatation, but all cases of ataxia presented normal CT findings. Hypotonia had mild ventricular dilatation. Two of three mixed type cases had normal CT findings and another had mild ventricular dilatation. No correlation was found between ventricular dilatation and behaviour development, but statistically significant difference was found in the cases with 30 % or more Evans' ratio (P < 0.05). Prognosis of severe ventricular dilatation cases was poor. (author)

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…

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

Electrocardiographic findings related to aging

Energy Technology Data Exchange (ETDEWEB)

Ueda, Shoichi; Yano, Katsuhiko

1962-12-12

More than 3000 electrocardiographic tracings for the ABCC-JNIH Adult Health Study Sample were studied to detect any specific abnormalities or nonspecific age changes in relation to possible radiation effects upon the cardiovascular system. The 4 comparison groups were studied with respect to the prevalence of electrocardiographic abnormalities and an electrocardiographic aging index which was defined to evaluate physiological change with age. Statistically significant differences were observed in the following aspects: In males aged 50 to 59, the prevalence of major electrocardiographic abnormalities was highest in the group located nearest the hypocenter. This was not observed in other age groups. In females, the prevalence of QRS high voltage was highest in Group 2 but low in Group 1. This trend was consistent in all age groups. These findings were not fully accounted for by differences in blood pressure, heart size, body weight or serum cholesterol values. In the age trend curve of the electrocardiographic aging index, a difference was observed among comparison groups in both sexes. This difference in electrocardiographic aging index is mainly attributed to T/sub I/ amplitude for males and R/sub II/ amplitude and QRS axis for females. Interpretation of these findings is rather difficult since very little has been known about radiation effects upon the cardiovascular system in humans. Further intensive studies are desired on the basis of the clues suggested in this report. 16 references, 3 figures, 31 tables.

Gift from statistical learning: Visual statistical learning enhances memory for sequence elements and impairs memory for items that disrupt regularities.

Science.gov (United States)

Otsuka, Sachio; Saiki, Jun

2016-02-01

Prior studies have shown that visual statistical learning (VSL) enhances familiarity (a type of memory) of sequences. How do statistical regularities influence the processing of each triplet element and inserted distractors that disrupt the regularity? Given that increased attention to triplets induced by VSL and inhibition of unattended triplets, we predicted that VSL would promote memory for each triplet constituent, and degrade memory for inserted stimuli. Across the first two experiments, we found that objects from structured sequences were more likely to be remembered than objects from random sequences, and that letters (Experiment 1) or objects (Experiment 2) inserted into structured sequences were less likely to be remembered than those inserted into random sequences. In the subsequent two experiments, we examined an alternative account for our results, whereby the difference in memory for inserted items between structured and random conditions is due to individuation of items within random sequences. Our findings replicated even when control letters (Experiment 3A) or objects (Experiment 3B) were presented before or after, rather than inserted into, random sequences. Our findings suggest that statistical learning enhances memory for each item in a regular set and impairs memory for items that disrupt the regularity. Copyright © 2015 Elsevier B.V. All rights reserved.

Generalized t-statistic for two-group classification.

Science.gov (United States)

Komori, Osamu; Eguchi, Shinto; Copas, John B

2015-06-01

In the classic discriminant model of two multivariate normal distributions with equal variance matrices, the linear discriminant function is optimal both in terms of the log likelihood ratio and in terms of maximizing the standardized difference (the t-statistic) between the means of the two distributions. In a typical case-control study, normality may be sensible for the control sample but heterogeneity and uncertainty in diagnosis may suggest that a more flexible model is needed for the cases. We generalize the t-statistic approach by finding the linear function which maximizes a standardized difference but with data from one of the groups (the cases) filtered by a possibly nonlinear function U. We study conditions for consistency of the method and find the function U which is optimal in the sense of asymptotic efficiency. Optimality may also extend to other measures of discriminatory efficiency such as the area under the receiver operating characteristic curve. The optimal function U depends on a scalar probability density function which can be estimated non-parametrically using a standard numerical algorithm. A lasso-like version for variable selection is implemented by adding L1-regularization to the generalized t-statistic. Two microarray data sets in the study of asthma and various cancers are used as motivating examples. © 2014, The International Biometric Society.

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.

comparison of clinical features and CT findings between atypical thymoma and thymic carcinoma

International Nuclear Information System (INIS)

Wang Xiangyang; Tan Ye; Chen Juan; Wei Jiahu; Pan Jishun; Du Jun; Zhou Cheng

2011-01-01

Objective: To investigate the differences and the similarities of clinical presentations and CT features between type B3 thymoma (atypical thymoma) and type C thymoma (thymic carcinoma) in the WHO classification of thymic epithelial tumors. Methods: Complete CT findings of thirty cases of type B3 and seventeen cases of type C thymic epithelial tumors confirmed by histopathology according to WHO 2004 Classification System and clinical features including the prognosis of each case were reviewed retrospectively. Statistical analyses of the data for the age and the long diameter were performed with Independent-Samples t test between the two groups. Statistical analysis for gender, association with myasthenia gravis, method of the operation, contours, shapes, calcification,necrosis, enhancement pattern of the tumors on CT, presence of mediastinal lymphadenopathy, invasion of mediastinal fat, chest wall, pericardium, great vessel, pleural mediastinum, metastasis to the plural, pleural effusion, distant metastasis were performed with Fisher exact test. Kaplan-Meier method was employed for survival analysis. Results: Clinical data: the average age of type B3 group was significantly younger (t=-2.905, P=0.006). 90.0% (27/30) of patients in type B3 group were complicated by myasthenia gravis, while only 5.9% (1/17) of patients in type C group were complicated by myasthenia gravis. The difference between the two groups was statistically significant (P=0.000). The ratio of complete resection of type B3 group (80.0%) was significantly higher than that in type C group (P=0.001), 70.6% (12/17) of patients in type C group died within 2 years after surgical resection, while only 20.0% (6/30) of patients in type B3 group died within one to nine years after surgical resection. Three years' survival ratio of C group was 29.4%, and five years' survival ratio of C group was lower than 14.7%, which was significantly lower than B3 group five years' survival ratio was 94.7%), which was

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

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.