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: [169.421, 88.16]

SOLUTION: 128.791

PROBLEM: [-19.13, 98.86, 158.686, 230.23]

SOLUTION: 117.161

PROBLEM: [33.912, -39.564, 217.066]

SOLUTION:
70.471