Editing Chi-squared test (section)

=== Fisher's exact test ===
For an [[exact test]] used in place of the 2 × 2 chi-squared test for independence when all the row and column totals were fixed by design, see [[Fisher's exact test]]. When the row or column margins (or both) are random variables (as in most common research designs) this tends to be overly conservative and [[Power (statistics)|underpowered]].<ref name="campbell2007">{{cite journal | last=Campbell | first=Ian | title=Chi-squared and Fisher–Irwin tests of two-by-two tables with small sample recommendations | journal=Statistics in Medicine | volume=26 | issue=19 | date=2007-08-30 | issn=0277-6715 | doi=10.1002/sim.2832 | pages=3661–3675| pmid=17315184 }}</ref>