# F Test Formula

A test statistic which has an F-distribution under the null hypothesis is called an F test. It is used to compare statistical models as per the data set provided or available. George W. Snedecor, in honour of Sir Ronald A. Fisher, termed this formula as F-test Formula.

F \; Value

\[\LARGE F \; Value \; = \; \frac{variance \; 1}{variance \; 2} = \frac{\sigma _{1}^{2}}{\sigma _{2}^{2}}\]

To compare variance of two different sets of values, F test formula is used. Applied on F distribution under null hypothesis, we first need to find out the mean of two given observations and then calculate their variance.

\[\LARGE \sigma^{2}\; = \; \frac{\sum (x – \overline{x})^{2}}{n-1}\]

Where,

σ^{2} = Variance

x = Values given in a set of data

$\overline{x}$ = Mean of the data

n = Total number of values.