text: For finding out the population variance in general:\n\n1. Find the arithmetic mean of the population concerned. \n2. For each member of the population,  find the value of its deviation from the arithmetic mean, and square it(by deviation I mean difference) . \n3. Add all the squares so obtained, and divide them by the population size. \n\nThe number that you would now obtain is the variance of the population. Hope this helps.