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: [155.723, 143.973, -89.725, -63.838, 82.645, -82.46, 119.929, 42.78, 230.62]

59.961