Chi-squared test

Chi-squared test (or $\mathrm {X} ^{2}$ test) is the name for a number of tests used in statistics. The values follow the chi-squared distribution. There are three main groups of tests:

• Tests for distribution check that the values follow a given probability distribution.
• Tests for independence check that the values are independent; if this is the case, no value can be left out without losing information.
• Tests for homogenity: These check that all samples taken have the same probability distribution, or are from the same set of values.