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: [20.002, 82.676, -51.919, 187.974, -25.189, 142.125, 202.897, 109.952]

83.565