Instructions: 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: [-19.273, 114.945, -15.716, 108.77, -56.249, 159.262, 26.992, -43.847, 214.335]
Output:
54.358