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: [68.635, 85.41, 234.806, 199.165, -83.691, 179.288, -81.042, 143.844, 20.881, -39.197]

72.81