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.

[80.346, 228.37, 18.978, -42.02]
71.419

[51.02, -71.125, 178.19, -7.234, -99.571, -17.215]
5.677

[71.387, 199.68, 103.183, 245.63, -78.931, 172.86, 22.14]

105.136