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: [159.34, 137.597, -74.489, -76.973, -38.902, 185.253, 40.413, 111.227]

55.433