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: [-12.821, 212.32, 117.75, -73.693, 1.379, 45.566, 132.444, 234.121, 157.978, 150.538]

96.558