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: [233.018, -85.207, 246.238, 217.62, 162.549, -92.137, -1.654, -17.538, -11.29]

72.4