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: [115.718, -24.175, -93.569, 91.172, -90.559, -11.885, 102.307, -64.17, 76.153, -87.658]

1.333