The cows have enrolled in elementary statistics and are having a tough time with their homework. Please help them.
Given a set of N (1 <= N <= 500) numbers, Xi (-5,000 <= Xi <= 5000),
calculate two statistics:
     * The mean (sum of the numbers divided by N)
     * The median (if N is odd, the middle number when the N numbers are sorted; if N is even, the mean of the two middle numbers when the N numbers are sorted)
Your answer will be considered correct if it is within 0.002 of the official answer.