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: [159.332, -99.73, -97.319, -0.091, 129.937, 152.291, -26.99, 80.148, -76.2, 86.403]

30.778