Unlike parametric statistics, which deals with tests for ratio and interval variables, nonparametric statistics deals with tests for nominal and ordinal variables.

It is then concluded that population parameters and estimates are disregarded in the following tests.

According to Fonseca (1996), nonparametric tests are very interesting for qualitative data when working with small samples (less than 30).

The main representatives of this statistic are the Chi Square, Wilcoxon, Mann-Whitney, Median, and Kruskall-Wallis tests.

Only the square chi will be approached as it is considered the most important and popular.

Next: Chi Square Test