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.
[238.695, -32.75, -11.325, -41.57, -47.99, 164.697, 218.758, 86.814, 176.681]