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.

[-42.207, -46.667, 171.095]
27.407

[196.683, 97.538, 247.799, 203.036, 203.369, -15.737]
155.448

[13.229, 7.664, -35.554, -10.329, 37.622, 120.378, -25.316, 215.976]

40.459