Sample Variance
Sample Variance is the sum of the squares of the distance each value is from the sample mean all divided by one less than the sample size.
That is if we denote the sample mean by \(\overline{x}\) and the number of elements of our sample data set as \(n\), i.e. \(S=\{x_1,...,x_n\}\), then we calculate the population standard deviation as:
\[s^2=\frac{\Big(\sum_{i=1}^n(x_i-\overline{x})^2\Big)}{{n-1}}\]
Note that we denote the sample variance with the letter \(s^2\) "s- squared"