| Abstract: | The effect of a test compound on neurogenically induced vasodilation in marmosets was studied using a non‐standard experimental design with overlapping dosage groups and repeated measurements. In this study, the assumption that the data were normally distributed seemed inappropriate, so no traditional data analyses could be used. As an alternative, a new permutation trend test was designed based on the Jonckheere–Terpstra test statistic. This test protects the type I error without any further assumptions. Statistically significant differences in trend between treatment groups were detected. The effect of the compound was then shown across doses using subsequent Wilcoxon rank‐sum tests against ordered alternatives. In all, the permutation test proved quite useful in this context. This nonparametric approach to the analysis may easily be adapted to other applications. Copyright © 2005 John Wiley & Sons, Ltd. |
