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: [199.242, 157.851, -17.266, 41.757, -4.215, 135.592, 25.369]

76.904