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: [-3.281, 84.204, -74.415, 151.616, 14.048, -98.313, 95.625, -79.981]
Example Output: 11.188

Example Input: [159.243, 17.964, 13.543, 175.402, -52.441, -34.741, 158.461]
Example Output: 62.49

Example Input: [72.882, 36.476, 231.44]
Example Output:
113.599