Averages are not good enough (2)

gistfile1.fs

let (|Even|Odd|) x =
	if x % 2 = 0 then Even
	else Odd

let median input = 
	let sortedInput = input |> Seq.sort
	let length = input |> Seq.length
	match length with
		| 0 -> raise <| new ArgumentException("Input sequence is empty")
		| 1 -> input |> Seq.nth 0
		| _ -> match length with
			| Even -> ( let first = sortedInput |> Seq.nth (length / 2 - 1)
						let second = sortedInput |> Seq.nth (length / 2)
						(first + second) / float 2)                             
			| Odd -> sortedInput |> Seq.nth ((length - 1) / 2)
				
// Median = 45.0
// 18 21 41 42 48 50 55 90
//          __ __