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: [51.455, 84.02, 192.884, 197.216, 4.149, -1.558, 97.546, 75.979, -81.102]

68.954