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Physical Sciences and Mathematics Commons

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Statistics and Probability

University of Massachusetts Amherst

Missing Data

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Full-Text Articles in Physical Sciences and Mathematics

Latent Class Models For At-Risk Populations, Shuaimin Kang Jul 2020

Latent Class Models For At-Risk Populations, Shuaimin Kang

Doctoral Dissertations

Clustering Network Tree Data From Respondent-Driven Sampling With Application to Opioid Users in New York City There is great interest in finding meaningful subgroups of attributed network data. There are many available methods for clustering complete network. Unfortunately, much network data is collected through sampling, and therefore incomplete. Respondent-driven sampling (RDS) is a widely used method for sampling hard-to-reach human populations based on tracing links in the underlying unobserved social network. The resulting data therefore have tree structure representing a sub-sample of the network, along with many nodal attributes. In this paper, we introduce an approach to adjust mixture models …


A Comparison Of Techniques For Handling Missing Data In Longitudinal Studies, Alexander R. Bogdan Nov 2016

A Comparison Of Techniques For Handling Missing Data In Longitudinal Studies, Alexander R. Bogdan

Masters Theses

Missing data are a common problem in virtually all epidemiological research, especially when conducting longitudinal studies. In these settings, clinicians may collect biological samples to analyze changes in biomarkers, which often do not conform to parametric distributions and may be censored due to limits of detection. Using complete data from the BioCycle Study (2005-2007), which followed 259 premenopausal women over two menstrual cycles, we compared four techniques for handling missing biomarker data with non-Normal distributions. We imposed increasing degrees of missing data on two non-Normally distributed biomarkers under conditions of missing completely at random, missing at random, and missing not …