Add and Calculate Sum: To find the mean of a set of numbers, we need to add all the numbers together and then divide by the number of numbers in the set.Calculation: (−7)+(−1)+(−9)+(−8)+(−3)+(−2)+(−2)+(−9)+(−5)+(−4)=−50Number of numbers in the set: 10
Divide to Find Mean: Now we divide the sum of the numbers by the number of numbers to find the mean.Calculation: −50÷10=−5