📸 Chi-Square Goodness of Fit in SPSS
Goodness of Fit vs. Test of Independence
The chi-square test of independence tests whether two variables are related. The chi-square goodness of fit test is different — it tests whether the observed frequency distribution of a single categorical variable matches a specified expected distribution.
Example: Are blood types distributed equally? Do patients' preferred treatment choices match population norms?
Running Goodness of Fit in SPSS
Step 1: Analyze → Nonparametric Tests → Legacy Dialogs → Chi-Square.
Step 2: Move the categorical variable to Test Variable List.
Step 3: Expected Values: "All categories equal" for uniform distribution. Or select "Values" and enter each category's expected proportion → OK.
📸 Goodness of fit test output
APA Reporting
A chi-square goodness of fit test indicated that the distribution of blood types in the patient sample differed significantly from population norms, χ²(3)=12.43, p=.006.