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: [82.878, -71.323, 6.874, 189.524, -80.172, -36.084, 163.231, 57.496, 93.812]

45.137