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: [30.224, 63.76, 96.876, 149.052, -38.974, 48.35, 133.493, 142.787, 10.958]

70.725