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: [214.749, -12.53, -14.167, -64.837, -7.259, -98.317, 242.557]

37.171