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: [232.583, 79.532, -20.355, -54.572, 148.178, 28.968, -89.316, -9.223, 162.433]

53.136