23 lines
386 B
Text
23 lines
386 B
Text
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class StdDevAccumulator(n=0, sum=0, sumofsquares=0) {
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method <<(num) {
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n += 1
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sum += num
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sumofsquares += num**2
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self
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}
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method stddev {
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sqrt(sumofsquares/n - pow(sum/n, 2))
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}
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method to_s {
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self.stddev.to_s
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}
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}
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var i = 0
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var sd = StdDevAccumulator()
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[2,4,4,4,5,5,7,9].each {|n|
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say "adding #{n}: stddev of #{i+=1} samples is #{sd << n}"
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}
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