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: [-3.836, 37.067, -16.403, 208.203, 178.783, 5.204, 83.722, 39.753, 19.525]

61.335