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: [-92.758, 186.47, 83.239, -95.255, -14.637, 161.829, 112.07, 227.775, -77.176]

54.617