Answer:
See below in BOLD.
Explanation:
Rearrange in ascending order of age:
11 11 11 12 12 13 14 15 15 16
1. The mean = (11 +11 +11 +12 +12 +13+ 14 +15+ 15+ 16) / 10
= 130/10
= 13 years.
2. The median is the mean of the middle 2 numbers in the list:
= (12 + 13) / 2
= 12.5 years.