standardDeviation :: [Double] -> Double
standardDeviation values =
  (sqrt . sum $ map (\x -> (x-mu)*(x-mu)) values) / sqrt_nm1
  where mu = average values
        sqrt_nm1 = sqrt (genericLength values - 1)
standardDeviation :: [Double] -> Double
standardDeviation values =
  (sqrt . sum $ map (\x -> (x-mu)*(x-mu)) values) / sqrt_nm1
  where mu = average values
        sqrt_nm1 = sqrt (genericLength values - 1)
standardDeviation values =
  (sqrt . sum $ map (\x -> (x-mu)*(x-mu)) values) / sqrt_nm1
  where mu = average values
        sqrt_nm1 = sqrt (genericLength values - 1)