mudphudder

non-parametric statistical tests

Nonparametric tests are also referred to as distribution-free tests. These tests are used when you cannot make the assumption of normality. Non-parametric tests compare medians rather than means and, as a result, if the data have one or two outliers, their influence is negated. But how do non-parametric tests compare to the usual parametric statistical tests? Here’s a table:

Parametric test	Non-parametric analogue
One-sample t-test	Nothing quite comparable
Paired sample t-test	Wilcoxon T Test
Independent samples t-test	Mann-Whitney U Test
Pearson’s correlation	Spearman’s correlation

(this table is as much a reminder for me as everyone else!!!)

3 Responses to “non-parametric statistical tests”

1
Emily:
January 15th, 2009 at 12:16 am
I think I love you!

You just condensed lots of information into only the important bits – in fact, you do that regularly.

So much awesomeness in one location! How can you stand it?
2
mudphudder:
January 15th, 2009 at 9:20 pm
I think I love me too
3
MomPhD:
June 8th, 2009 at 6:38 am
Thanks. That sure did come in handy!