Chi-Square Goodness of Fit Test
This test determines whether observed frequencies match expected frequencies based on a theoretical distribution (e.g., equal proportions, Mendelian ratios).
When to Use
- Testing if data follows a specific distribution
- Comparing observed to theoretically expected proportions
- One categorical variable with multiple levels
Examples
- Testing Mendelian inheritance ratios (3:1, 9:3:3:1)
- Checking if die is fair (equal 1/6 for each face)
- Testing equal preferences across categories
Null Hypothesis
H₀: Observed frequencies match expected frequencies