ASL STEM

Definition

The variance of a random variable or distribution is the expectation, or mean, of the squared deviation of that variable from its expected value or mean. Thus the variance is a measure of the amount of variation of the values of that variable, taking account of all possible values and their probabilities or weightings (not just the extremes which give the range).

Source: Wikipedia

Example

The variance of 3, 5, 7 = [(3-5)^2 + (5-5)^2 + (7-5)^2]/3 = 8/3