permutation

When we perform statistical tests, we often want to obtain a p-value, which describes the probability of obtaining test results at least as extreme as the observed result, assuming that the null hypothesis is true. In other words, how likely would it be to observe an effect as large (or larger) than the observed effect from chance and chance alone if the null is true? Common statistical approaches such as t-tests, ANOVAs, and linear regression make assumptions about the data or the errors.