That is if we denote the population variance as \(s^2\) and 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:

\[s=\sqrt{s^2}=\sqrt{\frac{\Big(\sum_{i=1}^n(x_i-\overline{x})^2\Big)}{{n-1}}}\]

Note that we denote the population standard deviation with the letter \(s\)