What is the mean of the set { 11, 10, 7, 9, 13 }?

Question

I don't understand this problem it keeps saying it's wrong idk when u put it in it says no incorrect.

Answer 1

The mean is the sum of the numbers divided by the number of numbers.  In this case, the five numbers add up to 50, and 50 / 5 = 10.  So the mean is 10.