                 gen <- newStdGen
                 let (prob, _) = randomR (min,max) gen :: (Float, StdGen)
                 return prob
                        

simulateReturns :: Float -> Int -> Float -> Float -> Float -> IO [Float]
simulateReturns sigma kbar gamma_kbar b m0 = do
  volatility <- simulateVolatility sigma kbar gamma_kbar b m0