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: [220.962, 208.438, 236.846, 109.22, 52.06, -5.693, -89.2, 228.518]

120.144