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: [203.649, -89.756, 82.548, -80.391, 23.853, 249.433, 118.863, 171.13, 153.987, 127.428]

96.074