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.
Input: [129.886, 82.523, -97.826, 48.731, -42.834, 79.604, 16.917, -68.982]

18.502