First sort the given set - O(n logn) Then if the size is odd, the middle element if the size is even, then its the average of the two middle elements

you could do that in linear time if the array size is less than 5 - easy to find if more than 5, read first 5 elements. Eliminate the smallest and the largest. Now you have 3 elements. Read another 2 elements, compare to your 3 elements that you've read before. Eliminate smallest and largest. Continue doing that until you have less than 5 elements left and then easily find the middle element among the remaining ones.