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.
[49.319, 81.528, -74.362, 101.648, 76.452, 45.877, 242.448, 150.207, -70.206, -55.065]