- | Maximum likelihood estimate of a sample's variance.  Also known
-- as the population variance, where the denominator is /n/.
variance :: (G.Vector v Double) => v Double -> Double
variance samp
    | n > 1     = robustSumVar (mean samp) samp / fromIntegral n
    | otherwise = 0
    where
      n = G.length samp
{
variance :: (G.Vector v Double) => v Double -> Double
variance samp
    | n > 1     = robustSumVar (mean samp) samp / fromIntegral n
    | otherwise = 0
    where
      n = G.length samp

variance samp
    | n > 1     = robustSumVar (mean samp) samp / fromIntegral n
    | otherwise = 0
    where
      n = G.length samp
