Skewness
lastmod 2015-02-04created 2015-02-042 edits
In probability theory and statistics, skewness is a measure of the asymmetry of the probability distribution of a real-valued random variable. The skewness value can be positive or negative, or it can be undefined. When skewness is negative, the probability density function has a long tail on the left side, and more of the data, including the median, lies to the right. When skewness is positive, the probability density function has a long tail on the right side, and more of the data lies to the left. If the mean and the median are equal, the skewness is 0.