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: [-48.196, 15.566, 65.782, 174.566, -91.786, 52.379, 2.658, 76.856]
Example Output: 30.978

Example Input: [196.683, 97.538, 247.799, 203.036, 203.369, -15.737]
Example Output: 155.448

Example Input: [199.153, 182.13, -7.832, -60.259]
Example Output:
78.298