When checking on distribution of residuals among multiple groups of a variable, what is the cut-off to use nonparametric test? Is there a citation?

In the past, I used a 20% cut-off as a rule-of-thumb when making decision about use or not to use parametric procedure on a numerical response variables. For example, there would be a 3-factorial...

28 June 2021 9,639 0 View