Another simple calculation in PowerShell
function get-standarddeviation { [CmdletBinding()] param ( [double[]]$numbers ) $avg = $numbers | Measure-Object -Average | select Count, Average $popdev = 0 foreach ($number in $numbers){ $popdev += [math]::pow(($number - $avg.Average), 2) } $sd = [math]::sqrt($popdev / ($avg.Count-1)) $sd }
Get the numbers. Calculate the average as we saw last time.
Sum the square of the differences between each value and the mean. Divide by the number of samples minus 1 (corrects fro assumption we are dealing with a sample) and then take square root.