Note on the Equality of Variances in Two Sample t-Test

두 집단 평균 차이 검정에서 분산의 동질성에 관한 소고

  • Kim, Sang-Cheol (Department of Applied Statistics, Yonsei University) ;
  • Lim, Jo-Han (Department of Statistics, Seoul National University)
  • Published : 2010.01.31


Introductory statistic class proposes two tests for the equality of two population means according to the homogeneity of their variances. However, in practice, the variances are also unknown and practitioners often test their homogeneity before they do two sample t-test. This is also true in many popular statistical packages such as SAS and SPSS. In this paper, we study the type I error of this two stage procedure and propose a procedure to control it at a given significance level.


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