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: [126.003, -76.128, -30.337, 74.801, 65.633, 172.839, 187.609, 103.233]

77.957