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: [72.76, 55.649, 50.184, 158.286, 21.33, 107.318, 120.646, 12.147]

74.79