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: [231.352, -24.17]
Example Output: 103.591

Example Input: [165.647, 110.893, -83.152, -56.699, 19.53, 48.825, -64.043, 199.192, 249.46, 244.789]
Example Output: 83.444

Example Input: [104.213, 211.328, 143.706, 101.168, 188.58]
Example Output:
149.799

