📸 Fisher's Exact Test via SPSS Crosstabs → Chi-Square statistics
When Is Fisher's Exact Test Used?
Fisher's Exact Test is used for 2×2 contingency tables when chi-square assumptions are violated: specifically, when expected cell frequencies are below 5. While chi-square is an approximation, Fisher's test calculates the exact probability of obtaining the observed table (or more extreme) under the null hypothesis.
Rule of thumb: use Fisher's Exact Test when any expected frequency in a 2×2 table is below 5, or when n<20.
Running Fisher's Test in SPSS
Step 1: Analyze → Descriptive Statistics → Crosstabs. Place variables in Row and Column.
Step 2: Statistics → check Chi-square → Continue → OK.
Step 3: In the output, read the Fisher's Exact Test row, not the Pearson Chi-Square row.
📸 Fisher's Exact Test output
APA Reporting
Fisher's exact test indicated a significant association between treatment group and recovery status, p=.047. Fisher's exact test was used because expected cell frequencies were below 5 (minimum expected = 2.8).