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: [159.4, 171.158, 208.441, 137.746, 78.097, 223.679, 142.855, 50.38, 165.77, 228.185]

156.571