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: [-39.649, -90.089, -67.126, 5.692, -66.245, 237.786, -16.044, 11.185]

-3.061