Some Notes on the Use of “Exact” Methods in Toxicological Studies

Abstract

It is important that statistical tests should be reliable for small samples and rare events. Permutation tests (1) form an important class of tests that can provide “exact” results for small samples. Permutation tests themselves, however, have limitations which must be realized if they are to be used reliably. The paper shows, by illustrative examples, some uses and limitations of permutation tests.