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: [-93.873, 217.909, -85.155, 21.87, 65.662, 172.1, -21.035, -1.759, 83.798, -47.665]

31.185