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: [-0.057, 246.507, 159.815, -39.339, 174.445, 81.743, 89.753, -64.457, -33.64, 83.218]

69.799