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: [190.815, -38.448, 221.169, 214.219, -41.104, 70.021, 192.216, 180.356, 71.353]

117.844