Sample size comparison for two independent populations

독립인 두 모집단 설계에서의 표본수 비교

  • Ko, Hae-Won (Department of Biostatistics, The Catholic University of Korea) ;
  • Kim, Dong-Jae (Department of Biostatistics, The Catholic University of Korea)
  • 고해원 (가톨릭대학교 의학통계학교실) ;
  • 김동재 (가톨릭대학교 의학통계학교실)
  • Received : 2010.10.01
  • Accepted : 2010.11.23
  • Published : 2010.11.30


For clinical trials, it is common to compare the placebo and new drug. The method of calculating a sample size for two independent populations are the t-test that is used for parametric methods, and the Wilcoxon rank-sum test that is used in the non-parametric methods. In this paper, we propose a method that is using Kim's (1994) statistic power based on the linear placement statistic, which was proposed by Orban and Wolfe (1982). We also compare the sample size for the proposed method with that for using Wang et al. (2003)'s sample size formula which is based on Wilcoxon rank-sum test, and with that of t-test for parametric methods.


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