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: [10.216, 113.588, 134.786, 101.737, 147.605, 234.905, -97.513, -15.72]

78.7