Module: Enumerable

Defined in:
lib/madvertise/ext/enumerable.rb

Instance Method Summary collapse

Instance Method Details

#mean ⇒ Object 



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# File 'lib/madvertise/ext/enumerable.rb', line 6

def mean
  sum.to_f / length
end

#percentile(pc) ⇒ Object 



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# File 'lib/madvertise/ext/enumerable.rb', line 19

def percentile(pc)
  sort[(pc * length).ceil - 1]
end

#stdev ⇒ Object 



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# File 'lib/madvertise/ext/enumerable.rb', line 15

def stdev
  Math.sqrt(variance)
end

#sum ⇒ Object 



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# File 'lib/madvertise/ext/enumerable.rb', line 2

def sum
  reduce(:+)
end

#variance ⇒ Object 



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# File 'lib/madvertise/ext/enumerable.rb', line 10

def variance
  m = mean
  reduce(0) {|accum, item| accum + (item - m) ** 2}.to_f / (length - 1)
end