To start, the mean of the answer is also known as the average value of a set of numbers. This is calculated by dividing the sum of the set by the total amount of numbers.
In this case the sum of all the numbers is 13 + 6 + 8 + 6 + 15 which is equal to 48.
Now, divide 48 by the total number of numbers in the set: 48/5 = 9.6
Your final answer should be 9.6, or you can leave it in fraction form as 48/5.