Solution:
       The median of a set of numbers arranged in ascending or descending order is the middle number.
        If there is an even number of items in the set, their median is the arithmetic mean of the middle two numbers

        numbers arranged:  1, 3, 4, 5, 6, 7, 8, 8  ( there is an even number of items: 8)

        1, 3, 4, 5, 6, 7, 8, 8  (5,6 the middle two numbers)

        (5 + 6)/2    (the arithmetic mean of the middle two numbers)

         11/2  = 5.5