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: [74.745, 42.031, 12.239, 127.71, 152.019, -84.989, 156.129, 90.627]

71.314