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: [-99.122, 150.232, 197.036, 229.069, 169.673, 249.51, 183.525, 167.158, -10.359, -6.982]

122.974