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: [21.953, -90.519, 92.624, 189.808, 130.57, -33.423, -16.126, 31.61, 119.582]

49.564