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: [-89.323, 135.914, 236.915, 121.352, 199.93, 205.53, 126.035, -90.563, -25.302]

91.165