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: [241.388, -37.843, -41.309, 26.588, 138.961, 235.54, -27.509]

76.545