Sample Size Re-Estimation Based on Two-Stage Analysis of Variance: Interim Analysis of Clinical Trials
Planning and conducting interim analysis are important steps for long-term clinical trials. In this article, the concept of conditional power is combined with the classic analysis of variance (ANOVA) for a study of two-stage sample size re-estimation based on interim analysis. The overall Type I and Type II errors would be inflated by interim analysis. We compared the effects on re-estimating sample sizes with and without the adjustment of Type I and Type II error rates due to interim analysis.