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: [110.249, 157.344, 198.65, 107.833, -2.52, 134.604, 57.996, -77.682, 214.709]

100.131