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: [169.165, 20.546, 83.84, -83.69, -12.496, 121.319, 33.638, -28.088, 111.189]

46.158