Class: Array

Inherits:
Object
  • Object
show all
Defined in:
lib/statistiks/array/sd.rb,
lib/statistiks/array/sum.rb,
lib/statistiks/array/mean.rb,
lib/statistiks/array/variance.rb,
lib/statistiks/array/percentile.rb

Instance Method Summary collapse

Instance Method Details

#mean(round = 5) ⇒ Object 



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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 ⇒ Object 



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# File 'lib/statistiks/array/percentile.rb', line 10

def median
  self.percentile(50)
end

#percentile(p) ⇒ Object 



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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 ⇒ Object 



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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) ⇒ Object 



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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) ⇒ Object 



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# File 'lib/statistiks/array/sum.rb', line 2

def sum(round = 5)
  self.inject(:+).round(round)
end

#variance(round = 5) ⇒ Object 



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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