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: [78.309, 113.056, 3.865, 202.756, 71.109, 1.263, 158.26, -26.552, 196.017, 110.39]

90.847