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: [54.838, 54.884, -49.76, 44.127, 207.55, -64.738, 102.633, 240.723, 160.019]

83.364