title: Find maximum, minimum and average in F#
body: <p>I want to find maximum, minimum and average in an array without .NET in F#.
  I used this code but it is not working:</p>
  
  <pre><code>let mutable max = 0
  let arrX = [|9; 11; 3; 4; 5; 6; 7; 8|]
  
  for i in 0 .. arrX.Length - 2 do
    if (arrX.[i]) &lt; (arrX.[i+1]) then 
         max &lt;- arrX.[i]
         printfn "%i" max
  </code></pre>