The median of the given set of numbers is determined by rearranging them in ascending or descending order and selecting the middle number. Since the number of responses are even, we would find the mean of the two middle numbers. Rearranging the numbers in ascending order, it becomes
6, 12, 12, 13, 13, 15
The median = (12 + 13)/2 = 12.5
Mean = sumof responses/number of responses
Mean = (6 + 12 + 12 + 13 + 13 + 15)/6
Mean = 9.3