Variance

Variance is a measure of how much values in a data set differ from the mean. Do scores tend to center around the mean or are they spread out? For example, take two data sets each with 7 scores ranging from 1 to 9 and a mean of 5. The set with scores [1, 1, 3, 5, 7, 9, 9] has greater variance than the set with scores [1, 3, 5, 5, 5, 7, 9].