Statistics - parametric and nonparametric
Parametric statistics are based on assumptions about the distribution of population from which the sample was taken. Nonparametric statistics are not based on assumptions, that is, the data can be collected from a sample that does not follow a specific distribution.
Common parametric statistics are, for example, the Student's t-tests. Common nonparametric statistics are, for example, the Mann-Whitney-Wilcoxon (MWW) test or the Wilcoxon test.