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: [204.239, 162.75, -27.965, 90.425, 147.912, 25.99, -22.763, 109.311]

86.237