Categorized or continuous? Strength of an association - and linear regression

摘要

Our previous article in this series considered analysis of variance,1 which is applied to measurements made of samples fromdifferent groups. That approach considers the variation of thedata, and specifically the variation between samples, which isrelated to the presence of different levels of the factor related toa group. The variation between samples is contrasted with theresidual variation, found within the samples. We consider thepossibility that the groups could be different, because of the differentconditions of a factor.