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: [174.309, -18.898, 212.555, 54.589, -70.15, 240.867, 61.917, -57.06]

74.766