There is no difference between the sum of squares for sample data and population data, except that instead of the sample mean M, you use the population mean μ, and instead of the sample size n, your sample size is denoted N. However, if this set of scores is considered a population instead of a sample, what was denoted as M is μ, and what was denoted as n is N. Thus, the sum of squares is identical regardless of whether this set of scores is considered a sample or a population.
