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: [226.287, 114.252, -53.47, 8.606, 234.708, -31.872, 163.615]
Example Output: 94.589

Example Input: [113.021, 101.946, -14.79, -8.555, -59.095, -74.169, 80.193, 157.87, 26.321, -19.87]
Example Output: 30.287

Example Input: [154.805, -99.136, 113.495, -58.447]
Example Output:
27.679