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: [102.57, 163.024, 156.925, 36.367, 198.354, 74.888, -25.537, 225.018, 242.473, -82.995]

109.109