StATS: Parametric versus nonparametric tests (March 9, 2004)
One of the biggest areas of disagreement among statisticians is when to use parametric or non-parametric statistics. I got an inquiry about this today, and quite honestly, I don't think it matters all that much. One consideration is sample size--if your sample is large, then the assumption of normality is easily met because of the central limit theorem. I wrote up a brief page on the central limit theorem and linked to a few pages that show how the central limit theorem works.
This page was written by Steve Simon while working at Children's Mercy Hospital. Although I do not hold the copyright for this material, I am reproducing it here as a service, as it is no longer available on the Children's Mercy Hospital website. Need more information? I have a page with general help resources. You can also browse for pages similar to this one at Category: Unusual data.