Extending nondirectional heterogeneity tests to evaluate simply ordered alternative hypotheses

Abstract

Biologists frequently use nondirectional heterogeneity tests when comparing three or more populations because a suitable directional test is unavailable or is not practical to implement. Here we describe a test, the ordered heterogeneity test, that permits testing against simply ordered alternative hypotheses in the context of almost any nondirectional test. The test has a wide range of parametric and nonparametric applications. Graphs are developed for calculating exact P values.