Chi-Square Test Statistical test
What is Chi-Square?
The Chi-Square Test (chi2) is a statistical test for categorical data. It determines whether observed frequencies differ significantly from expected frequencies.
Types
Test of Independence
- Are two categorical variables related?
- Example: Is disease status associated with smoking?
Goodness of Fit
- Does data match expected distribution?
- Example: Are equal proportions of each blood type?
Interpretation
- p < 0.05: Significant association or deviation
- p >= 0.05: No significant association
Requirements
- Categorical data
- Expected frequencies >= 5 in each cell
- Independent observations
Related Terms
- P-Value: Significance of the test
- Contingency Table: Table of observed frequencies