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: [29.77, 19.24, 231.795, 175.293, -7.304, 206.231, -29.028, 184.234, 129.873, -79.392]

86.071