A statistical test commonly used for attribute or categorical data (i.e., to test for a fixed ratio, for independence in a contingency table, or for homogeneity of a ratio), for homogeneity of variance test, and for goodness of fit. Chi-square is a nonsymmetric, continuous probability distribution which is the null distribution, or asymptotic null distribution, of many test statistics including Bartlett's test for homogeneity of variance and the so called chi-square tests of goodness-of-fit and independence in contingency tables.