Now showing items 1-10 of 32
Latent Continuous Time Markov Chains for Partially-Observed Multistate Disease Processes
A disease process refers to a patient's traversal over time through a disease with multiple discrete states. Multistate models are powerful tools used to describe the dynamics of disease processes. Clinical study settings present modeling challenges, as patients' disease trajectories are only partially observed, and patients' ...
Latent Class and Latent Profile Analysis in Medical Diagnosis and Prognosis
Evaluating test accuracy is an important topic in medical diagnosis and prognosis. Accuracy information is necessary for care-givers to make well-informed decisions; it also helps researchers to select better diagnostic tools, either from new techniques or based on combinations of current information. This field has recently ...
Rare variant method for identity-by-descent detection in sequence data, and the time to most recent common ancestor given identity-by-descent segment length
Identity-by-descent (IBD) is defined as two individuals sharing a haplotype they have both inherited from a common ancestor, where a haplotype is a segment of genetic material found on a single homologue. Existing methods for IBD detection were written to analyze low-density SNP arrays. These methods may not be well-suited ...
Assessing measurement error correction for genotype imputation in GWAS
Abstract not available
The Bayesian Analysis of Data Arising from Complex Sampling Designs
The majority of this thesis concerns the development of Bayesian methods for two-phase studies. A two-phase study is a study design in which limited information (including outcome) is known for a large "first-phase" study population, and more extensive information is known for a "second-phase" subset of these individuals. The ...
Covariate Measurement Error Correction Methods in Mediation Analysis with Failure Time Data
Mediation analysis is important in understanding the mechanisms of one variable causing changes in another. Measurement error could be obscuring the ability of the potential mediator to explain this mechanism. Existing correction methods in mediation analysis literature are not directly applicable to failure time data. This ...
Methodology for Examining Differential Rates of Change for Longitudinal Data
A common objective for longitudinal studies is to characterize differences in the rate of growth, or rate of change of an outcome across covariate-defined groups. The statistical challenges and potential extensions of models for comparing rates of change are intriguing with a broad scope for improving scientific research. ...
Relationship of nighttime arousals and nocturnal cortisol in IBS and normal subjects
This study was a secondary analysis of data from a study investigating the association between inflammatory bowel syndrome (IBS) and nocturnal cortisol and catecholamines in a sample of IBS subjects and healthy controls. A mediation analysis found evidence consistent with the existence of a mediating effect by sleep disruption ...
Problems in Pedigrees and Phylogenies
The footprint of genetic inheritance can be observed among both familial relationships between individuals and evolutionary relationships between species. The former can be depicted by a pedigree, whereas the latter can be depicted by a phylogeny. These two distinct objects can be viewed as analogous, in the sense that they ...
Challenges Associated with Statistical Analysis in the Presence of Sparse Data and Applications to Alternative Tobacco Product Research
Rarely observed covariate combinations, or "sparsity" is a phenomenon associated with research concerning the health risks of alternative-use (non-combusted tobacco products (AUPs)). Of particular concern is sparsity relating to AUP users who do not currently or formerly use other tobacco products. This thesis aims to identify ...