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: [27.555, -5.84, 114.665, 4.729, 115.865, 51.116, -28.549, -57.693, -33.043, -83.201]

10.56