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: [230.375, -45.327, 112.137, 109.305]
Example Output: 101.622

Example Input: [-40.016, 117.495]
Example Output: 38.74

Example Input: [100.12, 196.476, -69.362, -98.278, -88.557, -78.605]
Example Output:
-6.368