Variance
Definition
The average squared deviation from the mean — a measure of spread. Standard deviation is its square root.
Example
Variance of {2, 4, 6}: mean is 4; squared deviations are 4, 0, 4; variance = 8/3.
The average squared deviation from the mean — a measure of spread. Standard deviation is its square root.
Variance of {2, 4, 6}: mean is 4; squared deviations are 4, 0, 4; variance = 8/3.