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: [-6.055, -15.916, -28.534, 104.283, -85.161, 214.43, 72.449, 192.727, 33.088]

53.479