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.

Example Input: [246.282, 231.815, 1.709, -51.234, -76.432, 21.802, 18.917, 106.734, 168.909, -67.647]
Example Output: 60.085

Example Input: [222.94, 54.014, 232.208, -16.089, 214.915, 2.232]
Example Output: 118.37

Example Input: [14.993, 170.321, -5.36, 120.151, -70.197, -22.28, 207.984, 235.405, -27.907, -93.801]
Example Output:
52.931

