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: [139.304, -83.145, 163.642, 43.653, 68.259, 229.97, 25.046, 121.49, 198.512, 39.247]

94.598