DOI
https://doi.org/10.25772/FAM3-EN68
Defense Date
2012
Document Type
Thesis
Degree Name
Master of Science
Department
Biostatistics
First Advisor
Wen Wan
Second Advisor
Robert E. Johnson
Abstract
The purpose of study is to check whether the power of detecting the effect of intervention versus control in a pre- and post-study can be increased by using a stratified randomized controlled design. A stratified randomized controlled design with two study arms and two time points, where strata are determined by clustering on baseline outcomes of the primary measure, is considered. A modified hierarchical clustering algorithm is developed which guarantees optimality as well as requiring each cluster to have at least one subject per study arm. The power is calculated based on simulated bivariate normal distributed primary measures with mixture normal distributed baseline outcomes. The simulation shows that the power of this approach can be increased compared with using a completely randomized controlled study with no stratification. The difference of the power between with stratification and without stratification increases as the sample size increases or as the correlation of the pre- and post-measures decreases.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
July 2012