Two alternative procedures are described for testing the significance of differences of group means. The first consists of a reduction in the critical value when comparing the largest and smallest means. The other alternative uses the unmodified range test without a preliminary F test. An example is provided. (Author/CTM)

Compares three methods of analyzing pairwise treatment differences in a multi-treatment experiment via computer simulation techniques. Under the equal n condition, the robustness of the conventional Tukey Wholly Significant Difference test (WSD) to heterogeneous variances was contrasted with two alternate techniques. Under unequal n conditions,…

Two issues in analysis of interactions in complex linear models are considered. One is the omnibus test for interaction, and the other concerns follow-up tests when the omnibus test is significant. Reconsidered omnibus and follow-up tests are illustrated on an educational data set analyzed using the Statistical Analysis System. (SLD)