The distribution of the chi-square statistic is called the chi-square distribution. In a statistical experiment of a random sample of size n, having a standard deviation equal to σ, the standard deviation of the sample is equal to s.
A statistic, called chi-square, is defined using the following equation:
Χ^2 = [ ( n - 1 ) * s^2 ] / σ^2
If this experiment is repeated an infinite number of times, a sampling distribution for the chi-square statistic is obtained.
The chi-square distribution has the following properties: