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: [32.458, 21.603, 243.923, 13.381, 148.655, -38.201, 231.847, 71.906, -5.428, -68.618]

65.153