Simultaneous One-Sided Pairwise Comparisons in a Two-Way Design

Cheung and Chan (1996) provided a procedure for simultaneous two-sided pairwise comparisons of treatment means in a two-way design. Expanding on this earlier work, we develop a procedure where all such comparisons are instead one-sided. The new procedure is appropriate in situations where the treatment means are a priori ordered. The overall type I error rate for the simultaneous inferences is controlled at a designated level. Tables of upper percentage points of the test statistic are given to facilitate the implementation of our method. The application of the testing procedure is illustrated with an example from a medical study.