Answer:
-1
Explanation:
The mean is simply the average of a given set of numbers.
The mean can be calculated by adding the values of each number in the set and then dividing that by the number of values in the set.
Here the sum of the given values of the set would be -3 + -8 + 12 + -15 + -9 = -5
There are a total of 5 number values given in the set
So the mean is equal to -5 / 5 = -1