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: [-84.771, 60.727, 165.566, 27.782, 159.929, 167.451, -64.15]
Example Output: 61.791

Example Input: [223.847, 115.483, 148.407, -44.824, 99.251, 36.833, -45.949]
Example Output: 76.15

Example Input: [-6.462, -14.924, 172.464, 225.877, 55.181]
Example Output:
86.427

