anchor.diff:  
   
       /// <summary>
  -    ///   Computes the truncated (trimmed) mean
  +    ///   Computes the truncated (trimmed) mean where x percent of the highest, and x percent of the lowest values are discarded (total 2x)
       /// </summary>
       ///
       /// <param name="items">The input sequence.</param>
  
negative.code:         let zero = LanguagePrimitives.GenericZero< 'U > 
          let n = Seq.length(data)
          if (n > 0) then    
              let k = int ((float n * percent))
              data
              |> Seq.sort
              |> Seq.skip k
              |> Seq.take (n - 2 * k)
              |> mean
  
          else
  