Module: Enumerable

Defined in:
lib/enumerable.rb

Overview

TODO: Avoid monkey-patching.

Instance Method Summary collapse

Instance Method Details

#mean ⇒ Object 



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# File 'lib/enumerable.rb', line 3

def mean
  self.reduce(:+) / self.length.to_f
end

#standard_deviation ⇒ Object 



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# File 'lib/enumerable.rb', line 12

def standard_deviation
  Math.sqrt(self.variance)
end

#variance ⇒ Object 



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# File 'lib/enumerable.rb', line 7

def variance
  mean = self.mean
  self.reduce(0) { |memo, value| memo + ((value - mean) ** 2) } / (self.length - 1).to_f
end