TASK DEFINITION: In this task you will be given a list of numbers and you need to find the mean (average) of that list. The mean of a list can be found by summing every number in the list then dividing the result by the size of that list. The output should be rounded to 3 decimal places.
PROBLEM: [21.531, 221.161, -31.194]

SOLUTION: 70.499

PROBLEM: [22.306, 72.768, 218.947, 52.973, 100.121, 157.59, -92.109]

SOLUTION: 76.085

PROBLEM: [-19.769, 147.929, -36.133, 201.287, 28.528, -6.089, 122.533, 127.892, -36.662]

SOLUTION:
58.835