probability :: BinomialDistribution -> Int -> Double
probability (BD n p) k
  | k < 0 || k > n = 0
  | n == 0         = 1
  | otherwise      = choose n k * p^k * (1-p)^(n-k)
probability :: BinomialDistribution -> Int -> Double
probability (BD n p) k
  | k < 0 || k > n = 0
  | n == 0         = 1
  | otherwise      = choose n k * p^k * (1-p)^(n-k)
probability (BD n p) k
  | k < 0 || k > n = 0
  | n == 0         = 1
  | otherwise      = choose n k * p^k * (1-p)^(n-k)