Marshall Beddoe wrote:
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hstats-0.1
I've just released hstats, a statistical computing module for the Haskell language. Current functionality includes: mean, median, mode, range, standard/average deviation, variance, iqr, kurtosis, skew, covariance, and correlation. I have plans on adding more rank correlation functions, histograms & chi square tests.
Nice, I often prefer Haskell over gnuplot for quick & dirty data analysis :) An additional feature would be (linear) regression. Oh, and "automatic error bounds", i.e. representing a value together with its standard derivation much like automatic differentiation data Floating a => Value a = V { value :: a, stdderiv :: a} and arithmetic operations like x + y = V (value x + value y) (sqrt $ stdderiv x ^2 + stdderiv y ^2) The drawback is that the usual laws for +,- and * are broken here, so care has to be taken for choosing formulas. Also, are the formulas for mean etc. numerically stable? I don't remember very well, but I think I've read that mean = foldl' (\(!n,!s) x -> (n+1, s+(x-s)/(fromIntegral $ n+1)) (0,0) is better than the standard sum xs / length xs formula. Or at least that the latter is not good. Regards, apfelmus