Statistics and Probability Commons^™

Trivials: The Birth, Sale, And Final Production Of Meta-Analysis, Shlomo S. Sawilowsky

Journal of Modern Applied Statistical Methods

The structure of the first invited debate in JMASM is to present a target article (Sawilowsky, 2003), provide an opportunity for a response (Roberts & Henson, 2003), and to follow with independent comments from noted scholars in the field (Knapp, 2003; Levin & Robinson, 2003). In this rejoinder, I provide a correction and a clarification in an effort to bring some closure to the debate. The intension, however, is not to rehash previously made points, even where I disagree with the response of Roberts & Henson (2003).

The Importance Of Fortran In The 21st Century, Walt Brainerd

Journal of Modern Applied Statistical Methods

A brief discussion on the history and purpose of Fortran for scientific and engineering computing is given. This leads to the role Fortran, in its various environments, will likely play well into the 21st century.

A Parametric Bootstrap Version Of Hedges’ Homogeneity Test, Wim Van Den Noortgate, Patrick Onghena

Journal of Modern Applied Statistical Methods

Hedges’ Q-test is frequently used in meta-analyses to evaluate the homogeneity of effect sizes, but for several kinds of effect size measures it does not always appropriately control the Type 1 error probability. Therefore we propose a parametric bootstrap version, which shows Type 1 error control under a broad set of circumstances. This is confirmed in a small simulation study.

Fast Permutation Tests That Maximize Power Under Conventional Monte Carlo Sampling For Pairwise And Multiple Comparisons, J. D. Opdyke

Journal of Modern Applied Statistical Methods

While the distribution-free nature of permutation tests makes them the most appropriate method for hypothesis testing under a wide range of conditions, their computational demands can be runtime prohibitive, especially if samples are not very small and/or many tests must be conducted (e.g. all pairwise comparisons). This paper presents statistical code that performs continuous-data permutation tests under such conditions very quickly – often more than an order of magnitude faster than widely available commercial alternatives when many tests must be performed and some of the sample pairs contain a large sample. Also presented is an efficient method for obtaining a …

Screening Properties And Design Selection Of Certain Two-Level Designs, H. Evangelaras, Christos Koukouvinos

Journal of Modern Applied Statistical Methods

Screening designs are useful for situations where a large number of factors (q) is examined but only few (k) of these are expected to be important. It is of practical interest for a given k to know all the inequivalent projections of the design into the k dimensions. In this paper we give all the inequivalent projections of inequivalent Hadamard matrices of order 28 into k=3 and 4 dimensions and furthermore, we give partial results for k=5. Then, we sort these projections according to their generalized resolution and their generalized aberration.

Analyzing Group By Time Effects In Longitudinal Two-Group Randomized Trial Designs With Missing Data, James Algina, H. J. Keselman, Abdul R. Othman

Journal of Modern Applied Statistical Methods

We investigated bias, sampling variability, Type I error and power of nine approaches for testing the group by time interaction in a repeated measures design under three types of missing data mechanisms. One procedure due to Overall, Ahn, Shivakumar, and Kalburgi (1999) performed reasonably well over a range of conditions.

A More Efficient Way Of Obtaining A Unique Median Estimate For Circular Data, B. Sango Otieno, Christine M. Anderson-Cook

Journal of Modern Applied Statistical Methods

The procedure for computing the sample circular median occasionally leads to a non-unique estimate of the population circular median, since there can sometimes be two or more diameters that divide data equally and have the same circular mean deviation. A modification in the computation of the sample median is suggested, which not only eliminates this non-uniqueness problem, but is computationally easier and faster to work with than the existing alternative.

You Think You’Ve Got Trivials?, Shlomo S. Sawilowsky

Journal of Modern Applied Statistical Methods

Effect sizes are important for power analysis and meta-analysis. This has led to a debate on reporting effect sizes for studies that are not statistically significant. Contrary and supportive evidence has been offered on the basis of Monte Carlo methods. In this article, clarifications are given regarding what should be simulated to determine the possible effects of piecemeal publishing trivial effect sizes.

A Semiparametric Regression Model For Oligonucleotide Arrays, Jianhua Hu, Guosheng Yin

Journal of Modern Applied Statistical Methods

A semiparametric model incorporating the spline smoothing technique is proposed to study oligonucleotide gene expression data. No specific parametric functional form is assumed for mismatch probe intensities, which allows much more flexibility in the fitted model. The new approach improves the model fitting, hence the estimation of expression indexes. The method is applied to a data set of 18 HuGeneFL arrays.

Jmasm6: An Algorithm For Generating Exact Critical Values For The Kruskal-Wallis One-Way Anova, Todd C. Headrick

Journal of Modern Applied Statistical Methods

A Fortran 77 subroutine is provided for computing exact critical values for the Kruskal-Wallis test on k independent groups with equal or unequal samples sizes. The subroutine requires the user to provide sorting and ranking routines and a uniform pseudo-random number generator. The program is available from the author on request.

Randomization Technique, Allocation Concealment, Masking, And Susceptibility Of Trials To Selection Bias, Vance W. Berger, Costas A. Christophi

Journal of Modern Applied Statistical Methods

It is widely believed that baseline imbalances in randomized clinical trials must necessarily be random. Yet even among masked randomized trials conducted with allocation concealment, there are mechanisms by which patients with specific covariates may be selected for inclusion into a particular treatment group. This selection bias would force imbalance in those covariates, measured or unmeasured, that are used for the patient selection. Unfortunately, few trials provide adequate information to determine even if there was allocation concealment, how the randomization was conducted, and how successful the masking may have been, let alone if selection bias was adequately controlle d. In …

Improved Multiple Comparisons With The Best In Response Surface Methodology, Laura K. Miller, Ping Sa

Journal of Modern Applied Statistical Methods

A method to construct simultaneous confidence intervals about the difference in mean responses at the stationary point and at x for all x within a sphere with radius I R is proposed. Results of an efficiency study to compare the new method and the existing method by Moore and Sa (1999) are provided.

The Global Dynamics Of Isothermal Chemical Systems With Critical Nonlinearity, Yi Li, Yuanwei Qi

Mathematics and Statistics Faculty Publications

In this paper, we study the Cauchy problem of a cubic autocatalytic chemical reaction system u_1,t = u_1,xx − u^α₁ u^β₂, u_2,t = du_2,xx+ u^α₁ u^β₂ with non-negative initial data, where the exponents α,β satisfy 1<α,βd>0 is the Lewis number. Our purpose is to study the global dynamics of solutions under mild decay of initial data as |x|→∞. We show the exact large time behaviour of solutions which is universal.

Machine Learning Approaches For Determining Effective Seeds For K -Means Algorithm, Kaveephong Lertwachara

Doctoral Dissertations

In this study, I investigate and conduct an experiment on two-stage clustering procedures, hybrid models in simulated environments where conditions such as collinearity problems and cluster structures are controlled, and in real-life problems where conditions are not controlled. The first hybrid model (NK) is an integration between a neural network (NN) and the k-means algorithm (KM) where NN screens seeds and passes them to KM. The second hybrid (GK) uses a genetic algorithm (GA) instead of the neural network. Both NN and GA used in this study are in their simplest-possible forms.

In the simulated data sets, I investigate two …

The Government As Litigant: Further Tests Of The Case Selection Model, Theodore Eisenberg, Henry Farber

Cornell Law Faculty Publications

We develop a model of the plaintiff's decision to file a lawsuit that has implications for how differences between the federal government and private litigants translate into differences in trial rates and plaintiff win rates at trial. Our case selection model generates a set of predictions for relative trial rates and plaintiff win rates, depending on the type of case and whether the government is defendant or plaintiff. To test the model, we use data on about 474,000 cases filed in federal district court between 1979 and 1994 in the areas of personal injury and job discrimination, in which the …

Virginia's Capital Jurors, Stephen P. Garvey, Paul Marcus

Cornell Law Faculty Publications

Next to Texas, no state has executed more capital defendants than Virginia. Moreover, the likelihood of a death sentence actually being carried out is greater in Virginia than it is elsewhere, while the length of time between the imposition of a death sentence and its actual execution is shorter. Virginia has thus earned a reputation among members of the defense bar as being among the worst of the death penalty states. Yet insofar as these facts about Virginia's death penalty relate primarily to the behavior of state and federal appellate courts, they suggest that what makes Virginia's death penalty unique …

Statistical Process Control: An Application In Aircraft Maintenance Management, Bradley A. Beabout

Theses and Dissertations

Maintenance management at the 135th Airlift Wing, Maryland Air National Guard desires a visualization tool for their maintenance performance metrics. Currently they monitor their metrics via an electronic spreadsheet. They desire a tool that presents the performance information in a graphical manner. This thesis effort focuses on the development of a visualization tool utilizing two of the seven tools offered by Statistical Process Control (SPC). This research demonstrates the application of p-charts and Pareto diagrams in the aircraft maintenance arena. P-charts are used for displaying mission capable (MC) rates and flying scheduling effectiveness (FSE) rates. Pareto diagrams are then used …

Ua56/1 Fact Book, Wku Institutional Research

WKU Administration Documents

Statistical and demographic profile of WKU.

Perturbation Of Global Solution Curves For Semilinear Problems, Philip Korman, Yi Li, Tiancheng Ouyang

Mathematics and Statistics Faculty Publications

We revisit the question of exact multiplicity of positive solutions for a class of Dirichlet problems for cubic-like nonlinearities, which we studied in 161. Instead of computing the direction of bifurcation as we did in [6], we use an indirect approach, and study the evolution of turning points. We give conditions under which the critical (turning) points continue on smooth curves, which allows us to reduce the problem to the easier case of f (0) = 0. We show that the smallest root of f (u) does not have to be restricted.

An Algebraic Characterization Of Projective-Planar Graphs, Lowell Abrams, Dan Slilaty

Mathematics and Statistics Faculty Publications

We give a detailed algebraic characterization of when a graph G can be imbedded in the projective plane. The characterization is in terms of the existence of a dual graph G∗ on the same edge set as G which satisfies algebraic conditions inspired by homology groups and intersection products in homology groups.

Multiple Solutions For An Inhomogeneous Semilinear Elliptic Equation In Rn, Yinbin Deng, Yi Li, Xuejin Zhao

Mathematics and Statistics Faculty Publications

No abstract provided.

Identifying Minimum G Aberration Designs For Hadamard Matrices Of Order 28, Steffany Belcher-Novosad, Debra Ingram

Journal of the Arkansas Academy of Science

No abstract provided.

Victim Characteristics And Victim Impact Evidence In South Carolina Capital Cases, Theodore Eisenberg, Stephen P. Garvey, Martin T. Wells

Cornell Law Faculty Publications

This article is available at:

http://scholarship.law.cornell.edu/facpub/290/.

The use of victim impact evidence (VIE) has been a standard feature of capital trials since 1991, when the Supreme Court lifted the previously existing constitutional bar to such evidence. Legal scholars have almost universally condemned the use of VIE, criticizing it on a variety of grounds.

Yet little empirical analysis exists that examines how VIE influences the course and outcome of capital trials. Moreover, the handful of empirical analyses that do exist rely on data gathered in simulation studies. Although valuable contributions have emerged from these experimental studies, such studies have often-rehearsed …

Victim Characteristics And Victim Impact Evidence In South Carolina Capital Cases, Theodore Eisenberg, Stephen P. Garvey, Martin T. Wells

Cornell Law Faculty Publications

The use of victim impact evidence (VIE) has been a standard feature of capital trials since 1991, when the Supreme Court lifted the previously existing constitutional bar to such evidence. Legal scholars have almost universally condemned the use of VIE, criticizing it on a variety of grounds. Yet little empirical analysis exists that examines how VIE influences the course and outcome of capital trials. We analyze the influence of VIE based on interviews with over two-hundred jurors who sat on capital trials in South Carolina between 1985 and 2001.

First, we describe the VIE introduced at sentencing trials, using a …

Nullification At Work? A Glimpse From The National Center For State Courts Study Of Hung Juries, Paula Hannaford-Agor, Valerie P. Hans

Cornell Law Faculty Publications

In recent years, the criminal justice community has become increasingly concerned about the possibility that jury nullification is the underlying motivation for increasing numbers of acquittals and mistrials due to jury deadlock in felony jury trials. In this Article, the authors discuss the inherent difficulty in defining jury nullification and identifying its occurrence in actual trials. They review the evolution in public and legal opinion about the legitimacy of jury nullification and contemporary judicial responses to perceived instances of jury nullification. Finally, the authors examine the possible presence of jury nullification through empirical analysis of data collected from 372 felony …

How Employment-Discrimination Plaintiffs Fare In The Federal Courts Of Appeals, Kevin M. Clermont, Theodore Eisenberg, Stewart J. Schwab

Cornell Law Faculty Publications

Employment-discrimination plaintiffs swim against the tide. Compared to the typical plaintiff, they win a lower proportion of cases during pretrial and after trial. Then, many of their successful cases are appealed. On appeal, they have a harder time in upholding their successes, as well in reversing adverse outcome.

This tough story does not describe some tiny corner of the litigation world. Employment-discrimination cases constitute an increasing fraction of the federal civil docket, now reigning as the largest single category of cases at nearly 10 percent.

In this article, we use official government data to describe the appellate phase of this …

On The Misuse Of Confidence Intervals For Two Means In Testing For The Significance Of The Difference Between The Means, George W. Ryan, Steven D. Leadbetter

Journal of Modern Applied Statistical Methods

Comparing individual confidence intervals of two population means is an incorrect procedure for determining the statistical significance of the difference between the means. We show conditions where confidence intervals for the means from two independent samples overlap and the difference between the means is in fact significant.

Constructive Criticism, Ronald C. Serlin

Journal of Modern Applied Statistical Methods

Attempts to attain knowledge as certified true belief have failed to circumvent Hume’s injunction against induction. Theories must be viewed as unprovable, improbable, and undisprovable. The empirical basis is fallible, and yet the method of conjectures and refutations is untouched by Hume’s insights. The implications for statistical methodology is that the requisite severity of testing is achieved through the use of robust procedures, whose assumptions have not been shown to be substantially violated, to test predesignated range null hypotheses. Nonparametric range null hypothesis tests need to be developed to examine whether or not effect sizes or measures of association, as …

Extensions Of The Concept Of Exchangeability And Their Applications, Phillip I. Good

Journal of Modern Applied Statistical Methods

Permutation tests provide exact p-values in a wide variety of practical testing situations. But permutation tests rely on the assumption of exchangeability, that is, under the hypothesis, the joint distribution of the observations is invariant under permutations of the subscripts. Observations are exchangeable if they are independent, identically distributed (i.i.d.), or if they are jointly normal with identical covariances. The range of applications of these exact, powerful, distribution-free tests can be enlarged through exchangeability- preserving transforms, asymptotic exchangeability, partial exchangeability, and weak exchangeability. Original exact tests for comparing the slopes of two regression lines and for the analysis of …

A Test Of Symmetry, Abdul R. Othman, H. J. Keselman, Rand R. Wilcox, Katherine Fradette, A. R. Padmanabhan

Journal of Modern Applied Statistical Methods

When data are nonnormal in form classical procedures for assessing treatment group equality are prone to distortions in rates of Type I error and power to detect effects. Replacing the usual means with trimmed means reduces rates of Type I error and increases sensitivity to detect effects. If data are skewed, say to the right, then it has been postulated that asymmetric trimming, to the right, should be better at controlling rates of Type I error and power to detect effects than symmetric trimming from both tails of the data distribution. Keselman, Wilcox, Othman and Fradette (2002) found that Babu, …