Definition: 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.
Input: [-65.796, 225.256, -90.863, -31.223, -16.891, 225.033, 249.122, 140.638, 30.242]

73.946