Variance: An Overview Standard deviation and variance are two basic mathematical concepts that have an important place in ...

Standard deviation measures how far numbers in a data set are spread out from an average value. In investing, it is used as a measurement of portfolio volatility.

Standard deviation is calculated by first subtracting the mean from each value, and then squaring, adding, and averaging the differences to produce the variance. Variance is itself a useful ...

The technical definition of standard deviation is somewhat complicated. First, for each data value, find out how far the value is from the mean by taking the difference of the value and the mean.