Standard Deviation

Standard deviation:

(1)
\begin{align} s = \sqrt {\frac{{\sum\nolimits_{j = 1}^N {{{\left( {{X_j} - \bar X} \right)}^2}} }}{{N - 1}}} \end{align}

where $\bar X$ is an arithmetic mean.

Standard deviation is a square root of Variance.

page revision: 4, last edited: 19 Jun 2011 12:45