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: [-53.388, 31.309, 19.079, -16.926, 242.421, 210.599]
Example Output: 72.182

Example Input: [245.271, 40.965, 133.913, 212.104]
Example Output: 158.063

Example Input: [193.323, 35.708]
Example Output:
114.516