Pearson chi-square test

n. A set of tests used with categorical data in which the degree to which a data set fits a theoretical distribution is calculated. It is often called a goodness of fit test as it tests how well a distribution fits actual data or how well two data sets fit each other. For instance, a chisquare test of the proportion of ethnic groups in a sample can be compared to the distribution of the groups in the population as a way of thinking about the appropriateness of a sample to make inferences about the population. Also called chi-square test.