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: [-71.118, 160.927, 230.116, -26.655, -4.297, 64.272, 72.304, 41.517, 242.068]
Example Output: 78.793

Example Input: [138.526, 60.81, 233.845, -33.602, 189.784, 13.888, 184.543, 53.635, 18.299, -87.132]
Example Output: 77.26

Example Input: [188.727, 75.518, 33.819, -59.29, 245.889, -87.245, 67.812, 178.693, -46.386, -98.263]
Example Output:
49.927