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: [210.354, 91.127, 51.505, -84.377, -68.134, 100.685, 241.744, -99.032, -56.574, -85.971]

30.133