Chi-squared and Fisher exact test

[oic...@gmail.com]

Hello,
I wonder if the Fisher exact test is automatically launched when the next warning appears:
Aviso en chisq.test(xx, correct = correction) :
Chi-squared approximation may be incorrect
If not, what may I do?
Thanks,

[Isaac Subirana]

compareGroups function automatically performs Fisher exact test when some cells have an expected frequency lower than 5. Every time a categorical variable is compared between groups, compareGroups first computes a chisq test. That's why a warnign appears when expected frequencies are <5. However, the p-value finally reported are the ones obtained by Fisher exact test.

Regards,

Isaac.