module DescriptiveStatistics::Shape
Public Instance Methods
kurtosis()
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# File lib/descriptive-statistics/shape.rb, line 10 def kurtosis return if length == 0 return 0 if length == 1 sum_quarted_deviation / ((length - 1) * quarted_standard_deviation.to_f) end
skewness()
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# File lib/descriptive-statistics/shape.rb, line 4 def skewness return if length == 0 return 0 if length == 1 sum_cubed_deviation / ((length - 1) * cubed_standard_deviation.to_f) end
Private Instance Methods
cubed_standard_deviation()
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# File lib/descriptive-statistics/shape.rb, line 23 def cubed_standard_deviation standard_deviation ** 3 end
quarted_standard_deviation()
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# File lib/descriptive-statistics/shape.rb, line 32 def quarted_standard_deviation standard_deviation ** 4 end
sum_cubed_deviation()
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# File lib/descriptive-statistics/shape.rb, line 18 def sum_cubed_deviation precalculated_mean = mean inject(0) {|sum, value| sum + (value - precalculated_mean) ** 3} end
sum_quarted_deviation()
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# File lib/descriptive-statistics/shape.rb, line 27 def sum_quarted_deviation precalculated_mean = mean inject(0) {|sum, value| sum + (value - precalculated_mean) ** 4} end