From AMS Glossary
Revision as of 19:59, 26 January 2012 by Perlwikibot
Departure from symmetry.
In statistics, the coefficient of skewness γ1 of a random variable or of a probability distribution is defined as γ1 = μ3/σ3, where μ3 is the third moment about the mean and σ is the standard deviation. Where γ1 > 0 the typical curve trails off toward the right and hence is said to be skewed to the right; when γ1 < 0 the longer tail is on the left, and the curve is said to be skewed to the left.