lib/exonio/statistical.rb
def median(numbers_ary)
      numbers_ary.sort!
      len = numbers_ary.length
      (numbers_ary[(len - 1) / 2] + numbers_ary[len / 2]) / 2.0
    end
def median(numbers_ary)
      numbers_ary.sort!
      len = numbers_ary.length
      (numbers_ary[(len - 1) / 2] + numbers_ary[len / 2]) / 2.0
    end
Median formula
 @param numbers_ary [array] an array of numbers

 @return [float]

 @example
   Exonio.median([1,2,3,4,5]) # => 3.0