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: [242.481, -6.824, -8.251, 146.425, 140.969, 6.919, -83.599, -59.12, 124.042]

55.894