Mega Code Archive
Get sigma value
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def mean(x)
sum=0
x.each {|v| sum += v}
sum/x.size
end
def variance(x)
m = mean(x)
sum =0.0
x.each {|v| sum += (v-m)**2 }
sum/x.size
end
def sigma(x)
Math.sqrt(variance(x))
end
data = [2,3,2,2,3,4,5,5,4,3,4,1,2 ]
puts sigma(data) # 1.20894105
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