# What is a chi-squared distribution?

##### 1 Answer

The chi-square distribution is one of the most commonly used distributions and is the distribution of the chi-square statistic.

#### Explanation:

The chi-square distribution is one of the most commonly used distributions. It is the distribution of the sum of squared standard normal deviates. The distribution's mean is equal to the degrees of freedom and the variance of the chi-square distribution is two multiplied by the degrees of freedom.

This is the distribution used when conducting a chi square test comparing observed versus expected values and when conducting a chi square test to test for differences in two categories.

Critical values for the chi-square distribution can be found here.

A related Socratic answer that may be helpful is this one on the relationship between the standard normal and chi-square distributions. For even more detail, see here.