# Contingency table

From AMS Glossary

## contingency table

A table showing the joint or compound frequencies of occurrence of two or more variables or attributes.

The simplest example is the so-called fourfold table in which two attributes

*A*and*B*are each divided into two classes, say*A*_{1},*A*_{2}, and*B*_{1},*B*_{2}, thus giving rise to four possible combinations: (*A*_{1},*B*_{1}), (*A*_{1},*B*_{2}), (*A*_{2},*B*_{1}), and (*A*_{2},*B*_{2}). The contingency table then displays the frequency of each of the four combinations.