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: [28.138, 41.76, -20.597, 60.157, 148.058, -74.272, -76.477, 38.343, 227.036, 141.991]

51.414