15 lines
257 B
Ruby
15 lines
257 B
Ruby
require 'facets/math/sum'
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require 'facets/math/mean'
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module Math
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# The sum of the squared deviations from the mean.
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#
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def self.summed_sqdevs(array)
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return 0 if array.size < 2
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m = mean(array)
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sum(array.map{ |x| (x - m) ** 2 })
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end
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end
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