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: [-15.474, 64.567, -15.512, 191.204, 69.845, -67.49, 233.251, 88.357]

68.594