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: [11.642, -39.595, 23.351, 168.447, 244.85, 108.958, 80.422, -14.774, 138.977]

80.253