Determining the Sample Size and Power for Cox Regression Analysis

Statistical power is the probability of rejecting a false null hypothesis and a larger sample size will increase the power of test. In the process of computing power, the sample size is determined. Therefore, the power of the study should be determined before starting to work. Cox regression analysis is a popular method of survival analysis and it examines the relationship between survival times and one or more covariates. In this study, power and sample size of cox regression analysis is determined for different situations of parameters by creating of study designs. As results of calculation, the practical tables and suggestions about determining the appropriate sample size were presented to the researches for clinical study.