Module: Enumerable

Defined in:
lib/maths.rb

Overview

Add methods to Enumerable, which makes them available to Array

Instance Method Summary collapse

Instance Method Details

#mean ⇒ Object

mean of an array of numbers



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# File 'lib/maths.rb', line 9

def mean
  return self.sum/self.length.to_f
end

#sample_variance ⇒ Object

variance of an array of numbers



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# File 'lib/maths.rb', line 14

def sample_variance
  mean=self.mean
  sum=self.inject(0){|acc,i|acc +(i-mean)**2}
  return(1/self.length.to_f*sum)
end

#standard_deviation ⇒ Object

standard deviation of an array of numbers



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# File 'lib/maths.rb', line 21

def standard_deviation
  return Math.sqrt(self.sample_variance)
end

#sum ⇒ Object

sum of an array of numbers



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# File 'lib/maths.rb', line 4

def sum
  return self.inject(0){|acc,i|acc +i}
end