Final answer:
To find the average of a set of numbers, add all the numbers together and divide the sum by the total number of numbers.
Step-by-step explanation:
To find the average of a set of numbers, you add all the numbers together and then divide the sum by the total number of numbers. In this case, the set of numbers is {-100,97,83,21,-50,20,101,30}. Adding all the numbers together gives us a sum of -100+97+83+21-50+20+101+30 = 102. There are 8 numbers in the set, so the average is 102/8 = 12.75.