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: [62.793, 230.498, 115.136, 223.819, 228.298, 52.2, -16.393, 111.376, 248.459]

139.576