Definition:Mean Square

Definition
Let $S$ be a set of numbers.

The mean square of $S$ is the arithmetic mean of the squares of the elements of $S$:


 * $s^2 = \dfrac 1 n \displaystyle \sum_{i \mathop = 1}^n {x_i}^2$

where $S = \set {x_1, x_2, \ldots, x_n}$.