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.
Q: [-82.655, 69.809, 141.521, 57.91, 8.583]
A: 
39.034