Descriptive statistics - extend Ruby Enumerable for common stats methods

Descriptive Statistics is a small gem from Derrick Parkhurst that provides a few common statistics methods to Ruby’s Enumerable:

> require 'descriptive_statistics'
 => true 
> data = [2,6,9,3,5,1,8,3,6,9,2]
 => [2, 6, 9, 3, 5, 1, 8, 3, 6, 9, 2] 
> data.number
 => 11.0 
> data.sum
 => 54 
> data.mean
 => 4.909090909090909 
> data.median
 => 5.0 
> data.variance
 => 7.7190082644628095 
> data.standard_deviation
 => 2.778310325442932 
> data.percentile(70)
 => 6.0

Browse the source or fork on GitHub.

Update: Francois-Guillaume Ribreau has ported the project to JavaScript as a NPM package.

Update 2: Gleicon Moraes has created a Python port.