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I D Mitchell

Publications and source records attributed to I D Mitchell.

21 records · Page 2Linked to original sources
PubMedDate not supplied

Investigations into parametric analysis of data from in vivo micronucleus assays by comparison with non-parametric methods.

Data from micronucleus assays of 6 compounds were analysed by 3 non-parametric and 3 parametric methods. Two of the latter involved transformation of the data so several transformation strategies were investigated. It was concluded that the non-parametric Kolmogorov-Smirnov two-sample test was the most reliable method of analysis. None of the parametric solutions was entirely satisfactory. The Bayesian solution to the Behrens-Fisher problem of normal distributions with differing variances was an acceptable compromise after the data had been transformed by the inverse hyperbolic sine method applicable to negative binomials.

Animals↗
PubMedDate not supplied

Analysis of in vivo results of cyclophosphamide-induced chromosomal damage in mammals from sensitivity and statistical aspects.

Metaphase analysis, the micronucleus test, and the dominant lethal assay were performed in rodents with cyclophosphamide. The variance in the results indicated that use of binomial statistics (or the Poisson or normal approximations of this distribution) would be inappropriate for determination of significance. This conclusion was reinforced by finding that negative binomial distributions best explained certain aspects of the data, as well as being theoretically more likely. Because there was no simple significance test based on negative binomial statistics and there was some doubt about the distributional form, a distribution-free significance test seemed most appropriated. Thus a one-sided Kolomogorov-Smirnov two-sample test was used. Although both the dominant lethal assay and metaphase analysis proved superior to the micronucleus test in terms of degree of response, this advantage was more than offset by the lesser difficulties and greater number of cells that could be analyzed in the micronucleus assay.

Animals↗