skewness

Skewness

The skewness is a measure of the asymmetry of a distribution. It is calculated as the average of the cubed standardized deviations from the mean:

$$\gamma =\frac{1}{N}\sum _{i=1}^N{\left(\frac{x_i-\bar{x}}{\sigma }\right)}^3$$

$<0$ … left-skewed (long tail on the left)
$=0$ … symmetric around the mean
$>0$ … right-skewed (long tail on the right)