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: [88.724, 12.098, -74.935, 60.97, 159.794, 49.669, 84.371, 172.309, 190.247]

82.583