When to use Fisher's exact test?

medium

Answer

$2\times2 (or r\timesc) contingency table with small expected counts (E < 5) where chi-square approximation fails.$
$Computes an exact p-value from the hypergeometric distribution.$
$Slow for large tables.$
$Standard for small clinical trials, rare-event categorical data.$
${\chi}^{2}$

Check yourself — multiple choice

For continuous data
Exact p from hypergeometric on 2×2 (or r×c) tables — use when expected counts < 5 or chi-square fails
Same as t-test
Only large samples

Fisher exact: exact hypergeometric p on contingency tables; small counts.

#hypothesis-testing#parametric-tests

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