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.

[-51.625, 100.25, -75.262, -53.896]
-20.133

[126.453, 169.516, 109.837, 208.695, 113.906, 56.894, 171.345, 126.81]
135.432

[28.128, 24.252, 22.054, -87.294, 49.547, -7.212, 222.62, 168.289, -75.692]

38.299