class Array
Public Instance Methods
mean(round = 5)
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# File lib/statistiks/array/mean.rb, line 2 def mean(round = 5) (self.sum.to_f/self.length).round(round) end
median()
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# File lib/statistiks/array/percentile.rb, line 10 def median self.percentile(50) end
percentile(p)
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# File lib/statistiks/array/percentile.rb, line 2 def percentile(p) if p < 0 || p > 100 nil else self.sort[((p.to_f / 100.0) * self.length.to_f) - 0.5] end end
quartiles()
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# File lib/statistiks/array/percentile.rb, line 14 def quartiles [self.percentile(25), self.percentile(50), self.percentile(75)] end
sd(round = 5)
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# File lib/statistiks/array/sd.rb, line 2 def sd(round = 5) Math.sqrt(self.variance).round(round) end
sum(round = 5)
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# File lib/statistiks/array/sum.rb, line 2 def sum(round = 5) self.inject(:+).round(round) end
variance(round = 5)
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# File lib/statistiks/array/variance.rb, line 2 def variance(round = 5) mean = self.mean ((1.0/(self.length - 1))*self.map{ |x| (x - mean)**2 }.sum).round(round) end