In probability theory and statistics, skewness is a measure of the asymmetry of the probability distribution of a real-valued random variable about its mean. The skewness value can be positive, zero, negative, or undefined.

What does it mean when data is skewed?

Skewness refers to a distortion or asymmetry that deviates from the symmetrical bell curve, or normal distribution, in a set of data. If the curve is shifted to the left or to the right, it is said to be skewed.

What does a skewed graph mean?

A skewed (non-symmetric) distribution is a distribution in which there is no such mirror-imaging. For skewed distributions, it is quite common to have one tail of the distribution considerably longer or drawn out relative to the other tail. ... A "skewed left" distribution is one in which the tail is on the left side.