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: [-16.277, -33.061, -26.18, 140.323, 236.57, -28.594, -42.472, -57.826, 158.577, -49.267]

28.179