Statistics and Probability Commons^™

Semi-Parametric Regression For The Area Under The Receiver Operating Characteristic Curve, Lori E. Dodd, Margaret S. Pepe

UW Biostatistics Working Paper Series

Medical advances continue to provide new and potentially better means for detecting disease. Such is true in cancer, for example, where biomarkers are sought for early detection and where improvements in imaging methods may pick up the initial functional and molecular changes associated with cancer development. In other binary classification tasks, computational algorithms such as Neural Networks, Support Vector Machines and Evolutionary Algorithms have been applied to areas as diverse as credit scoring, object recognition, and peptide-binding prediction. Before a classifier becomes an accepted technology, it must undergo rigorous evaluation to determine its ability to discriminate between states. Characterization of …

Selective Multiple Imputation Of Keys For Statistical Disclosure Control In Microdata, Rod Little, Fang Liu

The University of Michigan Department of Biostatistics Working Paper Series

The fundamental tension in statistical disclosure control (SDC) of microdata is the trade-off between the protection of individual respondents and the release of enough information for statistical inferences. We consider microdata that include key variables that contain identifying information and target variables that include sensitive information. Releasing the original data may expose some individuals in the sample to high risk of disclosure; deleting key variables is a common approach, but this loses information for some statistical analysis. This paper proposes selective multiple imputation of key variables (SMIKe) as an alternative SDC technique between those two extremes, and applies SMIKe to …

Estimating Disease Prevalence In Two-Phase Studies, Todd A. Alonzo, Margaret S. Pepe

UW Biostatistics Working Paper Series

Disease prevalence is ideally estimated using a “gold standard” to ascertain true disease status on all subjects in a population of interest. In practice, however, the gold standard may be too costly or invasive to be applied to all subjects, in which case a two-phase design is often employed. Phase 1 data consisting of inexpensive and non-invasive screening tests on all study subjects are used to determine the subjects that receive the gold standard in the second phase. Naïve estimates of prevalence in two-phase studies can be biased (verification bias). Imputation and re-weighting estimators are often used to avoid this …

Checking Assumptions In Latent Class Regression Models Via A Markov Chain Monte Carlo Estimation Approach: An Application To Depression And Socio-Economic Status, Elizabeth Garrett, Richard Miech, Pamela Owens, William W. Eaton, Scott L. Zeger

Johns Hopkins University, Dept. of Biostatistics Working Papers

Latent class regression models are useful tools for assessing associations between covariates and latent variables. However, evaluation of key model assumptions cannot be performed using methods from standard regression models due to the unobserved nature of latent outcome variables. This paper presents graphical diagnostic tools to evaluate whether or not latent class regression models adhere to standard assumptions of the model: conditional independence and non-differential measurement. An integral part of these methods is the use of a Markov Chain Monte Carlo estimation procedure. Unlike standard maximum likelihood implementations for latent class regression model estimation, the MCMC approach allows us to …

Partial Auc Estimation And Regression, Lori E. Dodd, Margaret S. Pepe

UW Biostatistics Working Paper Series

Accurate disease diagnosis is critical for health care. New diagnostic and screening tests must be evaluated for their abilities to discriminate disease from non-diseased states. The partial area under the ROC curve (partial AUC) is a measure of diagnostic test accuracy. We present an interpretation of the partial AUC that gives rise to a new non-parametric estimator. This estimator is more robust than existing estimators, which make parametric assumptions. We show that the robustness is gained with only a moderate loss in efficiency. We describe a regression modelling framework for making inference about covariate effects on the partial AUC. Such …

An Oscillation Theorem For Discrete Eigenvalue Problems, Martin Bohner, Ondřej Došlý, Werner Kratz

Mathematics and Statistics Faculty Research & Creative Works

In this paper we consider problems that consist of symplectic difference systems depending on an eigenvalue parameter, together with self-adjoint boundary conditions. Such symplectic difference systems contain as important cases linear Hamiltonian difference systems and also Sturm-Liouville difference equations of second and of higher order. The main result of this paper is an oscillation theorem that relates the number of eigenvalues to the number of generalized zeros of solutions.

Nuclear Genes That Encode Mitochondrial Proteins For Dna And Rna Metabolism Are Clustered In The Arabidopsis Genome, Annakaisa Elo, Anna Lyznik, Delkin O. Gonzalez, Stephen D. Kachman, Sally A. Mackenzie

Department of Statistics: Faculty Publications

The plant mitochondrial genome is complex in structure, owing to a high degree of recombination activity that subdivides the genome and increases genetic variation. The replication activity of various portions of the mitochondrial genome appears to be nonuniform, providing the plant with an ability to modulate its mitochondrial genotype during development. These and other interesting features of the plant mitochondrial genome suggest that adaptive changes have occurred in DNA maintenance and transmission that will provide insight into unique aspects of plant mitochondrial biology and mitochondrial- chloroplast coevolution. A search in the Arabidopsis genome for genes involved in the regulation of …

Conjugated Linoleic Acid Does Not Improve Insulin Tolerance In Mice, Kimberly M Hargrave, Michael J. Azain, Stephen D. Kachman, Jess Miner

Department of Statistics: Faculty Publications

Objective: To determine if the addition or removal of dietary conjugated linoleic acid (CLA) would alter insulin tolerances in mice from two genetic lines.

Research Methods and Procedures: High metabolic rate (MH) and low metabolic rate (ML) mice were assigned to consume 1) a control diet ad libitum, 2) a control diet at a restricted intake, or 3) a diet containing 1% CLA ad libitum. After 9 weeks, an insulin tolerance test was conducted, and a portion of the mice were killed. All remaining mice consumed the control diet ad libitum. Insulin tolerance tests were conducted 11 and 32 days …

Comparing Bayes Model Averaging And Stacking When Model Approximation Error Cannot Be Ignored, Bertrand S. Clarke

Department of Statistics: Faculty Publications

We compare Bayes Model Averaging, BMA, to a non-Bayes form of model averaging called stacking. In stacking, the weights are no longer posterior probabilities of models; they are obtained by a technique based on cross-validation. When the correct data generating model (DGM) is on the list of models under consideration BMA is never worse than stacking and often is demonstrably better, provided that the noise level is of order commensurate with the coefficients and explanatory variables. Here, however, we focus on the case that the correct DGM is not on the model list and may not be well approximated by …

Pain And Distress Associated With Polyclonal Antibody Production: Discussion And Recommendations, The Humane Society Of The United States

ANIMAL RESEARCH

The Humane Society of the United States (HSUS) held a workshop in August 2002 in order to develop recommendations for minimizing pain and distress associated with polyclonal antibody (Pab) production. A small group of experts in the fields of antibody production, animal welfare, in vitro alternatives, and/or regulatory compliance participated in the roundtable discussion. The workshop was a scientifically based meeting, and recommendations were based on the extensive experience of the workshop participants as well as published literature regarding the relevant issues.

Participants recognized that insufficient attention has been paid to animal welfare aspects of Pab production, in part because …

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.

Impulse Control Of Stochastic Navier-Stokes Equations, J. L. Menaldi, S. S. Sritharan

Mathematics Faculty Research Publications

In this paper we study stopping time and impulse control problems for stochastic Navier-Stokes equation. Exploiting a local monotonicity property of the nonlinearity, we establish existence and uniqueness of strong solutions in two dimensions which gives a Markov-Feller process. The variational inequality associated with the stopping time problem and the quasi-variational inequality associated with the impulse control problem are resolved in a weak sense, using semigroup approach with a convergence uniform over path.

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.

Estimation Of Cumulative Incidence Functions In Competing Risks Studies Under An Order Restriction, Hammou El Barmi, Subhash C. Kochar, Hari Mukerjee, Francisco J. Samaniego

Mathematics and Statistics Faculty Publications and Presentations

In the competing risks problem an important role is played by the cumulative incidence function (CIF), whose value at time t is the probability of failure by time t for a particular type of failure in the presence of other risks. Its estimation and asymptotic distribution theory have been studied by many. In some cases there are reasons to believe that the CIFs due to two types of failure are order restricted. Several procedures have appeared in the literature for testing for such orders. In this paper we initiate the study of estimation of two CIFs subject to a type …

Census 2000 Demographic Profile Report Of The Older Adult Population In Cuyahoga, Lake, Geauga, Lorain And Medina Counties, Mark Salling, Sharon Bliss, Mcnamara, Brian

All Maxine Goodman Levin School of Urban Affairs Publications

No abstract provided.

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 …

Sibling Recurrence Risk Ratio Analysis Of The Metabolic Syndrome And Its Components Over Time., Wei J. Chen, Pi Hua Liu, Yen Yi Ho, Kuo Liong Chien, Min Tzu Lo, Wei Liang Shih, Yu Chun Yen, Wen Chung Lee

Faculty Publications

The purpose of this study was to estimate both cross-sectional sibling recurrence risk ratio (lambdas) and lifetime lambdas for the metabolic syndrome and its individual components over time among sibships in the prospectively followed-up cohorts provided by the Genetic Analysis Workshop 13. Five measures included in the operational criteria of the metabolic syndrome by the Adult Treatment Panel III were examined. A method for estimating sibling recurrence risk with correction for complete ascertainment was used to estimate the numerator, and the prevalence in the whole cohort was used as the denominator of lambdas. Considerable variability in the lambdas was found …

Applications Of Recursive Estimation Methods In Statistical Process Control, Shelton Peiris, Aerambamoorthy Thavaneswaran, David E. Allen, R. Mellor

Research outputs pre 2011

In recent years there has been a growing interest in recursive estimation techniques as applied to statistical process control (SPC). In cases where prior information about the processes are available, it is shown that procedures based on the “optimal” smoothing can be superior to the classical procedures like Shewhart’s CUSUM control charts (see, for instance, Thavaneswaran, McPherson and Abraham (1998)). This paper reviews the recursive algorithms based on EWMA (exponentially weighted moving average), DLM (dynamic linear modeling), KF (Kalman filtering) and OS (optimal smoothing) in statistical process control with correlated data. We also discuss various relationships among the asymptotic mean …

Some Evidence On The Information Content Of Undisclosed Limit Orders On The Asx, M. Aitken, David E. Allen, Wenling J. Yang

Research outputs pre 2011

This paper is concerned with investigating the information content of undisclosed limit orders, and identifying factors that affect their size, plus the examination of the brokers’ behaviour in using undisclosed orders. We adopt a sample of liquid stocks listed on the ASX, and our estimation results indicate that the size of undisclosed orders are affected by a number of factors. Given the ‘stealth trading’ pattern of behaviour observed in large disclosed orders, this paper provides evidence to support a similar pattern of behaviour in the case of undisclosed orders. Our model also provides an appropriate measure for estimating the size …

Effects Of Bank Funds Management Activities On The Disintermediation Of Bank Deposits, David E. Allen, Jerry T. Parwada

Research outputs pre 2011

This study investigates the alleged disintermediation of banks’ traditional deposit-taking in favour of investment management activities. Using data on Australian bank-affiliated funds and a nine-year record of the parent banks’ liability balances, this study finds that managed funds do not displace bank liabilities. Prudential capital adequacy requirements dissuade banks from using in-house managed investments as indirect conduits for raising funds in the same manner as deposit-taking.

Normal Mixture Models For Gene Cluster Identification In Two Dimensional Microarray Data, Eric Scott Harvey

Theses and Dissertations

This dissertation focuses on methodology specific to microarray data analyses that organize the data in preliminary steps and proposes a cluster analysis method which improves the interpretability of the cluster results. Cluster analysis of microarray data allows samples with similar gene expression values to be discovered and may serve as a useful diagnostic tool. Since microarray data is inherently noisy, data preprocessing steps including smoothing and filtering are discussed. Comparing the results of different clustering methods is complicated by the arbitrariness of the cluster labels. Methods for re-labeling clusters to assess the agreement between the results of different clustering techniques …