#### Statistics - Calculating Variance

I - Calculate the mean of the set. In the example, you add 1 + 2 + 3 + 4 to obtain the result of 10, and then you divide 10 by 4, which yields a mean of 2.5

II - Subtract each variable from the mean and square each answer. In the example, (1-2.5)^2 , (2-2.5)^2 , (3-2.5)^2 , (4-2.5)^2 ; which equals 2.25 , 0.25 , 0.25 , and 2.25

III - Add the numbers calculated in Step 2. In the example, 2.25 + 0.25 + 0.25 + 2.25 = 5

IV - Divide the number calculated in Step 3 by the number of variables. In the example, 5 is divided by 4, which yields a variance of 1.25