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.

Example Input: [82.748, 43.804, -13.469, 226.705, -7.478]
Example Output: 66.462

Example Input: [237.501, 67.08, 13.857]
Example Output: 106.146

Example Input: [-73.206, -14.222, 133.004, 204.681, 178.571, -87.802, -22.102, 14.535]
Example Output:
41.682