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: [82.748, 43.804, -13.469, 226.705, -7.478]
Example Output: 66.462

Example Input: [79.978, -44.051, 200.217, 142.486, -89.194, 55.999, 165.078, -3.615, 0.12, -44.323]
Example Output: 46.27

Example Input: [108.874, 56.014, 148.045, 246.685, 115.853, -2.791, 249.053, -51.407, 231.081, 57.763]
Example Output:
115.917

