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: [33.948, 132.405, -69.128, 33.296, 35.864, -58.743, 62.847, 237.149, 54.19]

51.314