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University of South Carolina

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Biostatistics

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Full-Text Articles in Medicine and Health Sciences

The Age Of E-Cigarette Initiation And Association With Frequency Of Use And Risk Of Combustible Tobacco Cigarette Smoking Initiation, Andy Hu Apr 2022

The Age Of E-Cigarette Initiation And Association With Frequency Of Use And Risk Of Combustible Tobacco Cigarette Smoking Initiation, Andy Hu

Senior Theses

Background - Studies have shown that electronic nicotine delivery systems (ENDS) are unsafe for consumption. However, the prevalence of e-cigarette use among adolescents and young adults continues to increase, which is being addressed by research. Little attention has been paid to the effects of earlier age of ENDS initiation.

Purpose - This paper examined published research studies on the topic of the age of initiation of e-cigarette use in relation to 1) frequency of e-cigarette use and 2) risk of combustible tobacco cigarette smoking initiation. This research tested the hypothesis that an earlier age of e-cigarette initiation was associated with …


Defining Septicemia Incidence And Mortality In South Carolina Through Access To Health Care, Behavioral Health, And Low Socio-Economic Status, Raeann Vossberg Apr 2021

Defining Septicemia Incidence And Mortality In South Carolina Through Access To Health Care, Behavioral Health, And Low Socio-Economic Status, Raeann Vossberg

Senior Theses

This study aims to provide an in-depth view of septicemia mortality and incidence in the state of South Carolina through the lenses of socio-economic factors, access to healthcare, and behavioral health factors. This study was conducted using data from the South Carolina Revenue and Fiscal Affairs Office, utilizing their Hospitalization, Inpatient, Emergency Department, and Outpatient data both separately and combined depending on the data point, along with additional data sources for support (see works cited). We hypothesize that the higher rates of septicemia mortality and incidence in the southeastern United States, as well as in South Carolina in particular, could …


Cluster Analysis With Batch Effect, Yifan Tang Jan 2015

Cluster Analysis With Batch Effect, Yifan Tang

Theses and Dissertations

Clustering, as a fundamental process in data science, is frequently used in preliminary data analysis. Batch effects are a powerful source of variation that can come from many sources in data collection, and influence data. We propose a method to simultaneously remove batch effects and perform cluster analysis. We see a batch effect as a fixed value added on to each batch, and do not make assumptions about the distribution of batch effects. We represent the data using a Gaussian mixture model, and use the EM algorithm to estimate the cluster means, the cluster covariance matrices, and the batch effects, …


Comparison Of Confidence Intervals Of Intracluster Correlation Coefficient Estimates For Binary Variables, Ashok Varma Samantapudi Jan 2014

Comparison Of Confidence Intervals Of Intracluster Correlation Coefficient Estimates For Binary Variables, Ashok Varma Samantapudi

Theses and Dissertations

The present study evaluates the length of the confidence interval and the percentage of time the true parameter is captured by the confidence interval for four intracluster correlation estimators. These are the ANOVA estimator, the Pearson pairwise estimator with constant weights (PEQ), the kappa type estimator called FC, and an estimator using a Resampling method (RM) for binary data. We compared these different estimates by using a large simulation study. The data we simulated is correlated binary data, which assumes an exchangeable correlation structure. We also included different variations of the number of clusters, cluster size, cluster size variation, event …