A measure of how variable a set of numbers are. Technically, it is the sum of squared deviations from the mean divided by (n-1) (the number of numbers in the sample minus one). Thus, to find the variance of the set of numbers 4, 6, and 8, we first calculate the mean, which is 6. We then sum the squared deviations from the mean (4 - 6)2 + (6 - 6)2 + (8 - 6)2, which comes to 8, and divide by (n-1) (which is 2 in this case). The variance of the three numbers is 8/2 = 4. The more variable the set of numbers, the higher the variance. The variance of a set of identical numbers (such as 6, 6, and 6) is zero.