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: [142.996, 219.102, -25.069, 89.381, 185.338, 153.662, 23.669]

112.726