title: Models and the use of signed rank tests.
abstract: Rank tests are often used to analyse medical and biological data. The lack of invariance of the paired sample Wilcoxon signed rank test with respect to transformation of observations, and the choice of an appropriate rank test in the case of the two way analysis of variance random effects model, are discussed in the context of two medical examples.
mesh_terms: D000704:Analysis of Variance; D001249:Asthma / Q000628:therapy; D001699:Biometry; D002986:Clinical Trials as Topic / Q000379:methods*; D003773:Dental Plaque / Q000517:prevention & control; D006801:Humans; D011897:Random Allocation