Calculate Skewness in R

Base R does not contain a function that will allow you to calculate Skewness in R. We will need to use the package “moments” to get the required function.

Skewness is a commonly used measure of the symmetry of a statistical distribution. A negative skewness indicates that the distribution is left skewed and the mean of the data (average) is less than the median value (the 50th percentile, ranking items by value). A positive skewness would indicate the reverse; that a distribution is right skewed. A right skewed distribution would be biased towards higher values, such that the mean of the distribution will exceed the median of the distribution.

Right Skewed distributions are fairly common in the social sciences and often indicate the presence of a handful of exceptionally high outliers. For example, look at the distribution of income and wealth in many societies. There is usually a handful of high observations which raise the average above the median value.

# calculate skewness in r
install.packages("moments")
library(moments)

> skewness(test)
[1] -0.296553

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