Analyses for Binomial Data, with Application to the Fluctuation Test for Mutagenicity

Publisher Website
Google Scholar
Abstract
The fluctuation test proposed by Green, Muriel and Bridges (1976, Mutation Research 38, 33-42), a short-term microbial test for mutagenicity, yields binomial observations for which the probability of success varies with the background mutation rate, the total number of microbial growth cycles for which a microbe is at risk of mutation, and the rate of induced mutation for the compound being tested. A standard one-tailed two-sample binomial test is preferable to the two-tailed test adopted by Green et al. for analyzing data from a control versus single positive dose fluctuation test. Based on exact power computations, recommendations are offered for the design of such a fluctuation test. A simple method of guarding against the impact of a small number of aberrant observations in a multisample binomial problem is studied; it is applicable to the fluctuation test when the protocol involves replicate measurements . Finally, the case of more than one positive dose of the test compound is investigated. Two statistical tests for this situation, both extensions of one-tailed two-sample test, are extensively compared. A departure from monotonicity at high doses has a more serious effect on the power of the 'regression' test than on that of the 'isotonic' test. A variant of the isotonic test, based on the angular transformation, should be avoided.

This publication has 0 references indexed in Scilit: