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: [94.64, 13.24, -67.221, -22.958, -92.145, 56.155, -54.903, 172.768, -68.936, 171.236]

20.188