# Skewness

From AMS Glossary

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## skewness

Departure from symmetry.

In statistics, the coefficient of skewness γ

_{1}of a random variable or of a probability distribution is defined as γ_{1}= μ_{3}/σ^{3}, where μ_{3}is the third moment about the mean and σ is the standard deviation. Where γ_{1}> 0 the typical curve trails off toward the right and hence is said to be skewed to the right; when γ_{1}< 0 the longer tail is on the left, and the curve is said to be skewed to the left.