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 4 def mean sum.to_f / length end |
#percentile(pc) ⇒ Object
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# File 'lib/madvertise/ext/enumerable.rb', line 17 def percentile(pc) sort[(pc * length).ceil - 1] end |
#stdev ⇒ Object
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# File 'lib/madvertise/ext/enumerable.rb', line 13 def stdev Math.sqrt(variance) end |
#variance ⇒ Object
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# File 'lib/madvertise/ext/enumerable.rb', line 8 def variance m = mean reduce(0) {|accum, item| accum + (item - m) ** 2}.to_f / (length - 1) end |