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: [213.817, 76.266, -73.455, -12.964, 189.174, 41.576, 156.04, 155.487]

93.243