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: [142.225, 243.809, -41.935, 96.795, -99.067, 222.292, 113.486, 143.726]

102.666