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: [98.967, 94.497, 2.134, 78.053, -78.517, 126.749, 87.549, 45.047, 51.818]

56.255