When to use the sample or population standard deviationWe are normally interested in knowing the population standard deviationbecause our population contains all the values we are interested in. Therefore,you would normally calculate the population standard deviation if: (1) you havethe entire population or (2) you have a sample of a larger population, but you areonly interested in this sample and do not wish to generalize your findings to thepopulation. However, in statistics, we are usually presented with a sample fromwhich we wish to estimate (generalize to) a population, and the standarddeviation is no exception to this. Therefore, if all you have is a sample, but youwish to make a statement about the population standard deviation from which thesample is drawn, you need to use the sample standard deviation. Confusion can
often arise as to which standard deviation to use due to the name "sample"standard deviation incorrectly being interpreted as meaning the standarddeviation of the sample itself and not the estimate of the population standarddeviation based on the sample.How to calculate grouped data standard deviation?Step by step calculation: Step 1: find the mid-point for each group or range of the frequency table.