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Chi-square test for goodness of fit

Definition

The chi-square test for goodness of fit is a statistical test that determines whether an observed frequency distribution differs significantly from an expected frequency distribution. It is commonly used when we want to assess how well observed data fits with theoretical expectations.

Analogy

Imagine you have a bag full of colored candies, and you want to know if they are distributed equally or not. The chi-square test for goodness of fit would be like counting how many candies you have in each color category and comparing it with what you would expect if they were evenly distributed.

Related terms

Contingency Table: A table that displays frequencies or proportions for multiple categorical variables, allowing us to examine relationships between them. It's like organizing data into compartments based on different characteristics, making it easier to analyze patterns.

Chi-square test for independence: A statistical test used to determine whether there is an association between two categorical variables. It helps us understand if changes in one variable are related to changes in another variable.

Expected Frequency: The number we would expect in each category or cell under the assumption that there is no relationship between variables being studied. It serves as a baseline for comparison with observed frequencies in order to assess deviations from expected patterns.