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: [15.293, 221.056, 241.387, 81.3, 102.644, 146.885, -33.65, -36.56, -69.176]

74.353