The data set for 10 a.m. has 25 numbers and the number in the middle is 40, so this is the median age. Because the data set for 6 p.m. has 27 numbers and the number in the middle is 17, this is the median age. So it is more likely that younger people who rollerblade will be at the mall at 6 p.m., which makes it a better time for Karen's presentation.