Physical Sciences and Mathematics Commons^™

Kendall's Tau And Spearman's Rho For Zero-Inflated Data, Ronald Silva Pimentel

Dissertations

Zero-inflated continuous distributions have positive probability mass at zero in addition to a continuous distribution. Such type of data can be encountered, for example, in medical, environmental and financial research. The main focus of this research is to study the association of nonnegative random variables, both having a positive probability mass at zero. New estimators of the classical measures of association, Kendall's tau and Spearman's rho, appropriate for the zero-inflated distributions, are proposed and their asymptotic distributions are derived. Performance of the estimators is assessed by a Monte Carlo simulation study. New ideas are illustrated by a real data example.

Metaevaluation Of Hiv/Aids Prevention Intervention Evaluations In Sub Saharan Africa With A Specific Emphasis On Implications For Women And Girls, Tererai Mafukidze Trent

Dissertations

Despite numerous attempts by international agencies to halt the spread of Human Immunodeficiency Virus (HIV) and Acquired Immunodeficiency Syndrome (AIDS), nowhere has the impact of HIV/AIDS been felt more acutely than among women and girls in Sub-Saharan Africa (SSA). SSA women account for 59% of adults over the age of 15 living with HIV/AIDS and 76% of those 15-24 who are infected (United Nations Joint Programme on HIV/AIDS [UNAIDS], 2007).

The evidence on gender disparities in infection rates is indisputable; there is an urgent need to identify what is missing in HIV/AIDS prevention interventions: What is the evidence based upon …

A Two-Sample Adaptive Procedure Based On The Log-Rank And Peto And Peto's Wilcoxon Tests, Annie A. Tordilla

Dissertations

It has been shown that under a location-scale model y = μ + βz + σε at where y is right censored, the Log-Rank test is asymptotically efficient for the Extreme minimum value error distribution while Peto and Peto's Wilcoxon test is asymptotically efficient for the Logistic error distribution. We propose a two-sample adaptive test, which first selects between Extreme minimum value and Logistic error distribution as to which is a better fit to the data, then performs the asymptotically efficient test (Log-Rank or Peto and Peto's Wilcoxon test) for the selected distribution. The performance of the adaptive test is …

The Program Evaluation Standards Applied For Metaevaluation Purposes: Investigating Interrater Reliabiity And Implications For Use, Lori A. Wingate

Dissertations

Metaevaluation is the evaluation of evaluation. Metaevaluation may focus particular evaluation cases, evaluation systems, or the discipline overall. Leading scholars within the discipline consider metaevaluation to be a professional imperative, demonstrating that evaluation is a reflexive enterprise. Various criteria have been set forth for what constitutes excellence in evaluation. In the context of educational program evaluation, the dominant criteria are the Program Evaluation Standards, developed by the developed by the Joint Committee on Standards for Educational Evaluation.

There has been widespread acceptance and application of the Program Evaluation Standards, and their use is advocated by major organizations and several of …

Test Procedures For Equality Of Two Variances In Delta Distributions, Jezaniah Kira Sarion Tena

Dissertations

Statistical literature on testing equality of variances is very broad, encompassing a great number of distributional variations. However, the case of a zero-inflated nonnegative continuous random variable has not yet been considered. Such distribution is specified by a positive probability that the variable assumes a true zero value, together with a conditional distribution for the positive values of the variable.

This study considers the special case, delta distribution, where the positive values come from the lognormal distribution. Test procedures were developed using a statistic based on Gini's Mean Difference. Since the asymptotic distribution of the test statistic was shown to …

Meta Analyses Of Multiple Baseline Time Series Design Intervention Models For Dependent And Independent Series, Oluwagbohunmi Adetunji Awosoga

Dissertations

Most wireless networks are deployed strictly in the radio frequency (RF) domain, since RF channels provide natural support for radial broadcast operations. However, the downside of RF channels is that they introduce many limiting externalities that make providing scalable quality of service (QoS) support difficult, if not intractable. These well-known technical challenges include bandwidth scarcity, lack of security, high interference, and high bit error rates.

Faced with such daunting obstacles to QoS, the use of Free Space Optics (FSO) for wireless communications has been proposed in which it has the potential to support higher link data rates compared to present …

Statistical Procedures For Bioequivalence Analysis, Srinand Ponnathapura Nandakumar

Dissertations

Applicants submitting a new drug application (NDA) or new animal drug application (NADA) under the Federal Food, Drug, and Cosmetic Act (FDC Act) are required to document bioavailability (BA). A sponsor of an abbreviated new drug application (ANDA) or abbreviated new animal drug application (ANADA) must document first pharmaceutical equivalence and then bioequivalence (BE) to be deemed therapeutically equivalent to a reference listed drug (RLD). The Average (ABE), Population (PBE) and Individual (IBE) bioequivalence have been used to establish the equivalence in the pharmaco-kinetics of drugs.

The current procedure of PBE uses Cornish Fisher's (CF) expansion on small samples. Since …

The Robustness Of Confidence Intervals For The Mean Of Delta Distribution, Mathew Anthony Cantos Rosales

Dissertations

The delta distribution is a mixture of a lognormal distribution and a distribution degenerate at zero. Interval estimators of the mean of delta distribution were proposed and examined under full assumption of the model. In this dissertation, robustness of these estimators is studied by comparing coverage properties when the data are contaminated. Simulation models have been considered to accommodate two types of contaminants: (1) data from lognormal distribution with higher level of skewness and (2) data from similar skewed distribution such as gamma, Weibull or Birnbaum-Saunders distributions with the same mean and variance as the original lognormal distribution. In addition, …