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: [19.893, 7.992, 71.926, 117.384, -47.437, 82.738, 166.352, 58.523, 181.442, 158.854]

81.767