STATISTICAL APPROACHES TO EXPERIMENTAL-DESIGN AND DATA-ANALYSIS OF IN-VIVO STUDIES

The objective of any experiment is to obtain an unbiased and precise e stimate of a treatment effect in an efficient manner. Statistical aspe cts of the design, conduct, and analysis of the experiment play a majo r role in determining whether this goal is met. We highlight some of t he more important statistical issues that pertain to in vivo studies. Particular emphasis is placed on the role of randomization, the number of animals, the utilization of repeated measures data, adjustments fo r missing data, and dealing with multiple causes of death or treatment failure. The discussion is not intended to be a comprehensive guide t o all the statistical issues that can occur in animal experiments. Rat her, the objective is to acquaint researchers with components of the e xperiment that will require careful statistical thought.