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: [234.272, 196.413, -92.425]
Example Output: 112.753

Example Input: [233.84, -38.337, 10.341, 195.901, 68.586, 214.429, 213.823, 88.799]
Example Output: 123.423

Example Input: [199.168, -13.333, 11.955, 127.827, 101.541, -23.333, 170.279, 29.964, -94.554, 158.28]
Example Output:
66.779