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: [-50.144, 0.802]
Example Output: -24.671

Example Input: [231.352, -24.17]
Example Output: 103.591

Example Input: [13.114, 167.099, 72.666, -94.604, -16.945]
Example Output:
28.266

