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.
[224.686, 145.683, 220.634, 227.57, 94.641, 119.892, -82.127, 141.411, 223.394]