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: [-31.225, 32.314, 25.235, 156.735, -42.066, 139.87, -12.819, 46.005, 142.618, -79.624]

37.704