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: [-28.435, -27.248, 207.783, 11.037, 69.144, 72.298, -15.965, 67.366, 180.976]

59.662