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: [-46.113, 125.487, 133.801, 230.957, 217.606, 147.203, -27.73, 66.455, -96.494]

83.464