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.
[-46.432, 71.258, 8.18, 239.612, 71.14, -41.758, 217.404, 75.711]