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: [72.326, -74.6, 127.566, -54.848, 198.529, -44.061, -28.155]
Example Output: 28.108

Example Input: [13.21, 76.551, 51.016, 230.763, 149.792, 157.216, 117.414, 144.272, 5.805, 118.165]
Example Output: 106.42

Example Input: [218.33, 160.735, 82.339, -7.711, 178.433, -4.988, 148.44, 179.731]
Example Output:
119.414