Multivariate one-sided multiple comparison procedure with a control based on the approximate likelihood ratio test.

In this study, we discuss a multiple comparison procedure with a control for multivariate one-sided test in each pairwise comparison. For pairwise comparisons, we use the approximate likelihood ratio test statistics derived by Tang et al. (An approximate likelihood ratio test for a normal mean vector with nonnegative components with application to clinical trials. Biometrika 1989, 76, 577-583). We derive a formula to determine the critical value for pairwise comparisons satisfying a specified significance level. Furthermore, we formulate the power of the test for our multiple comparison procedure. Finally, we give some numerical examples regarding the critical values and the power of the test.

Step down procedure for comparing several treatments with a control based on multivariate normal response.

In this study we consider a multiple comparison of several treatments with a control based on multivariate normal response in clinical trials. Specifically we construct a step down procedure by referring to Dunnett and Tamhane (1991). Furthermore we formulate the all-pairs power by using the recursive formula derived by Hayter and Tamhane (1991) and Dunnett, Horn and Vollandt (2001). Finally we compare the step down procedure with the single step procedure proposed by Nakamura and Imada (2005) in terms of some numerical examples regarding the power of the test.