Variance

The variance describes how spread out the data is, and mathematically is consisted of the average squared distance from the mean.

Mean

$$\mu (x)=\frac{1}{n}\sum _{i=1}^n{x}_i$$

Variance Calculation

$$VAR(x)=\frac{1}{n-1}\sum _{i=1}^n(x_i-\mu (x){)}^2$$