Type of Document Master's Thesis Author Hall, Kenita A URN etd-04232007-115823 Title ANALYZING THE BEHAVIOR OF RATS BY REPEATED MEASUREMENTS Degree Master of Science Department Mathematics and Statistics Advisory Committee
Advisor Name Title Dr. Yichuan Zhao Committee Chair Dr. Jun Han Committee Member Dr. Kyle Frantz Committee Member Dr. Yu-Sheng Hsu Committee Member Keywords
- Longitudinal Data
- Repeated Measurements
- Mixed Models
- Non-Linear Models
Date of Defense 2007-04-06 Availability unrestricted Abstract Longitudinal data, which is also known as repeated measures, has grown increasingly within the past years because of its ability to monitor change both within and between subjects. Statisticians in many fields of study have chosen this way of collecting data because it is cost effective and it minimizes the number of subjects required to produce a meaningful outcome. This thesis will explore the world of longitudinal studies to gain a thorough understanding of why this type of collecting data has grown so rapidly. This study will also describe several methods to analyze repeated measures using data collected on the behavior of both adolescent and adult rats. The question of interest is to see if there is a change in the mean response over time and if the covariates (age, bodyweight, gender, and time) influence those changes. After much testing, our data set has a positive nonlinear change in the mean response over time within the age and gender groups. Using a model that included random effects proved to be a better method than models that did not use any random effects. Taking the log of the response variable and using day as the random effect was overall a better fit for our dataset. The transformed model also showed all covariates except for age as being significant.Files
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