AP Stats Unit 8

Chi-Square Test for Goodness of Fit

A statistical test to determine whether a sample data matches a population with a specific distribution

Chi-Square Test for Independence

A statistical test to determine whether there is a significant association between two categorical variables

Chi-Square Test for Homogeneity

A statistical test to determine whether different populations have the same distribution of a single categorical variable

Expected Count

The theoretical frequency of an outcome, calculated under the assumption that the null hypothesis is true

Observed Count

The actual frequency of an outcome observed in the data

Chi-Square Statistic (χ²)

A measure of how much the observed counts deviate from the expected counts

Degrees of Freedom for Chi-Square Tests

Calculated as (number of rows - 1) × (number of columns - 1) for a contingency table