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: [-42.657, 223.632, 190.748, 118.681, 234.975, 102.985, 240.288, 15.492, 48.071]

125.802