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: [170.193, 3.616, 215.99, 173.329, 171.613, 193.589, 89.883, -69.397]

118.602