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: [19.301, -72.073, 13.843, -39.036, 23.681, 43.138, 172.434, -31.68]

16.201