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.
[132.338, -91.176, -50.214, 244.696, 90.308, 48.237, -28.224, 115.38]