Answer:
8
Step-by-step explanation:
One way to solve problems involving the mean of a data set is to consider the way the numbers relate to the mean.
When we subtract the mean from the given numbers, we find the differences are ...
-1, 1, 3, -3
The sum of these differences is 0. The missing number will make the toal of all differences from the mean be zero. Since it is already zero, the missing number is the mean. The missing number is 8.
