Method: Utilities::Statistics#variance

Defined in:
lib/utilities/utilities.rb

#variance(population = false) ⇒ Object

Return the variance of self



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# File 'lib/utilities/utilities.rb', line 64

def variance( population = false )
  return nil if empty?
  m = mean.to_f
  collect{|v| (v - m).square }.to_stats.sum / (size - (population ? 0 : 1))
end