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: [154.873, 44.322, 204.427, 29.301, 18.928, -78.456, -84.482]

41.273