Get Dylan’s median by putting his weekly sales into increasing order and finding the middle value. Dylan’s set is {2, 3, 9, 10}, and his median is the average of 3 and 9, or 6. Next, do the same thing for Peter’s sales numbers. Peter’s set is {4, 4, 6, 10}, so his median is the average of 4 and 6, which is 5. The difference between the medians is 6 − 5 = 1.