Chi Square is a distribution that has proven to be particularly
useful in statistics. The first section describes the basics
of this distribution. The following two sections cover
the most common statistical tests that make use of the
Chi Square distribution. The section "One-Way Tables" shows
how to use the Chi Square distribution to test the difference
between theoretically expected and observed frequencies.
The section "Contingency Tables" shows how to use Chi Square
to test the association between two nominal variables.
This use of Chi Square is so common that it is often referred
to as the "Chi Square Test."