Nonparametric statistics

When your data does not fit to a normal distribution, nonparametric statistical methods are required. A number of the nonparametric tests use ordinal data rather than numerical, with the data ranked and sorted in order. For example, nonparametric statistics could analyse a Likert scale ranking survey responses: Strongly Agree, Agree, Neither agree nor disagree, Disagree, Strongly Disagree.

 

Nonparametric statistical tests include:

Sign tests

Wilcoxon signed-rank test

Mann-Whitney U test

Kruskal-Wallis H test

Mood’s Median test

Friedman test