A Method for Testing Results of Infectivity Tests with Plant Viruses for Compatibility with Hypotheses

SUMMARY: A statistical method is described to test the compatibility between results of local-lesion counts and hypotheses relating changes in infectivity of plantvirus preparations to treatments applied to them. The method allows the varianceratio test to be applied: it involves establishing a relation between numbers of lesions and virus concentration for each experiment and a logarithmic transformation of lesion counts to make variance independent of the magnitude of the variate. Its use is illustrated with results obtained to see whether inactivation of viruses by ultraviolet radiation is a first order reaction.