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: [231.159, 217.795, 230.676, -11.951, -82.697, 31.413]
Example Output: 102.732

Example Input: [-19.13, 98.86, 158.686, 230.23]
Example Output: 117.161

Example Input: [-32.085, 196.699, 121.959, -59.257, 217.604, -19.786, -96.793]
Example Output:
46.906

