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: [-89.96, 150.865, 149.644, 226.39, 106.098, 237.886, -71.247]

101.382