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: [157.766, -45.853, -63.914, 169.231, -77.586, 62.681, 112.905, -72.059, 122.375, 42.288]

40.783