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: [9.281, 44.789, 159.19, 240.99, -85.827, 173.455, 218.464, 197.377, 78.015]

115.082