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: [103.476, 245.818, -36.218, 121.299, 25.636, 57.621, 84.397, 98.277, 52.464]

83.641