# Variance

In statistics, variance is the measure of the expected deviation from the mean. The square root of the variance is the standard deviation.

Variance is a college-level concept that would be first encountered in a probability and statistics course. It is an Advanced Placement Statistics topic and is listed in the California State Standards for Probability and Statistics.

### Prerequisites

Standard Deviation: | The standard deviation is a statistic defined as the square root of the variance that measures how spread out a set of data is. |