as we've seenpopulation variance is usually designated as sigma squared ( )with sigma (sas standard deviationand we can say that is the summation of each data point minus the meanmusquaredthat' the variance of each sample squared over nthe number of data points and we can express it with the following equationx denotes each data point denotes the mean denotes the number of data points sample variance similarly is designated as with the following equationx denotes each data point denotes the mean - denotes the number of data points minus that' all there is to it