A measure of the dispersion of data in statistics. For a set of values a1, a2, a3, … an, the mean m is given by (a1 + a2 + … + an)/n. The deviation of each value is the absolute value of the difference from the mean #|m – a1#|, etc. The standard deviation is the square root of the mean of the squares of these values, i.e. √[(#|m – a1#|2 + … #|m – an#|2)/n]
Subjects: Science and Mathematics.