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: [4.783, 144.804, -38.816, -15.415, 145.438, -78.709, 219.817, 220.045, -45.29, 50.036]

60.669