# Fisher Exact Test

Consider two dichotomous tests: [1 | 2] and [A | B] applied to a sample of size *N*.
Display the number of (A1), (B1), (A2), (B2) cases in a 2x2 contingency table:
A B
1 *a* *b*
2 *c* *d*

If the tests are independent, ratios should be equal (e.g., *a/c* = *b/d* )...
They rarely are equal, so the question is: are the ratios different enough
to reject the hypothesis of independence.
In the below table fill in the required values. All entries should be whole numbers!