when do you use chi square test as a statistical test
Chi-squared test A chi-squared test, also written as   χ 2   {\displaystyle \chi ^{2}}  test, is any statistical hypothesis test wherein the sampling distribution of the test statistic is a chi-squared distribution when the null hypothesis is true. Without other qualification, 'chi-squared test' often is used as short for Pearson's chi-squared test. The chi-squared test is used to determine whether there is a significant difference between the expected frequencies and the observed frequencies in one or more categories.