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: [-83.647, 205.771, -32.768, 197.698, 112.109, -91.453, 219.471, 242.747, 147.634]

101.951