That is if we denote the population variance as \(\sigma^2\) and the population mean by \(\mu\) and the number of elements of our population data set as \(n\), i.e. \(P=\{x_1,...,x_n\}\), then we calculate the population standard deviation as:

\[\sigma=\sqrt{\sigma^2}=\sqrt{\frac{\Big(\sum_{i=1}^n(x_i-\mu)^2\Big)}{n}}\]

Note that we denote the population standard deviation with the Greek letter \(\sigma\) "sigma"