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: [48.462, -80.347, -19.649, 180.664, -24.117]
Example Output: 21.003

Example Input: [134.631, 27.106]
Example Output: 80.868

Example Input: [248.169, 199.466]
Example Output:
223.818