what is standard deviation in investment terms
DEFINITION of 'Standard Deviation'. 1. A measure of the dispersion of a set of data from its mean. The more spread apart the data, the higher the deviation. Standard deviation is calculated as the square root of variance.2. In finance, standard deviation is applied to the annual rate of return of an investment to measure the investment's volatility. measure of the dispersion of a set of data from its mean. The more spread apart the data, the higher the deviation. Standard deviation is calculated as the square root of variance. 2.