Diversity prediction theorem: Difference between revisions

=={{header|Haskell}}==

<lang haskell>mean :: (Fractional a, Foldable t) => t a -> a

mean lst = sum lst / fromIntegral (length lst)

meanSq :: Fractional c => c -> [c] -> c

meanSq x = mean . map (\y -> (x-y)^^2)

diversityPrediction x estimates = do

putStrLn $ "TrueValue:\t" ++ show x

putStrLn $ "CrowdEstimates:\t" ++ show estimates

let avg = mean estimates

let avgerr = meanSq x estimates

putStrLn $ "AverageError:\t" ++ show avgerr

let crowderr = (x - avg)^^2

putStrLn $ "CrowdError:\t" ++ show crowderr

let diversity = meanSq avg estimates

putStrLn $ "Diversity:\t" ++ show diversity</lang>

<pre>λ> diversityPrediction 49 [48,47,51]

TrueValue: 49.0

CrowdEstimates: [48.0,47.0,51.0]

AverageError: 3.0

CrowdError: 0.11111111111111269

Diversity: 2.888888888888889

λ> diversityPrediction 49 [48,47,51,42]

TrueValue: 49.0

CrowdEstimates: [48.0,47.0,51.0,42.0]

AverageError: 14.5

CrowdError: 4.0

Diversity: 10.5</pre>