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: [62.982, 162.598, -87.283, -49.754, 3.283, -4.2, -20.891]

9.534