The F distribution

The F distribution is also known as Snedecor's F distribution or the Fisher–Snedecor distribution.

An f statistic is given by the following formula:

Here, s₁ is the standard deviation of a sample 1 with an n₁ size, s₂ is the standard deviation of a sample 2, where the size n₂σ₁ is the population standard deviation of a sample 1σ₂ is the population standard deviation of a sample 12.

The distribution of all the possible values of f statistics is called F distribution. The d1 and d2 represent the degrees of freedom in the following chart: