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: [16.256, 155.71, 43.059, -64.109, -42.445, 78.725, -12.941, 47.497]
Example Output: 27.719

Example Input: [220.903, 155.959]
Example Output: 188.431

Example Input: [50.385, -43.565, 52.271, 204.418]
Example Output:
65.877

