The χ2 statistic, also known as chi-square statistic, measures how well observed data fits expected data according to a certain hypothesis. It is commonly used in tests involving categorical variables.
Related terms
Degrees of Freedom: Represents the number of categories minus one for which values can vary freely after certain restrictions are imposed on them.
P-value: A probability associated with the χ2 statistic that indicates whether observed differences between expected and observed data are statistically significant.
Contingency Table: A table that displays the frequency or count of observations falling into different categories for two categorical variables. It is often used in χ2 tests.