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.

[138.602, 158.458, 241.327, 194.509, 169.45, -56.151]
141.032

[217.978, 70.977, 31.129, -87.408, -99.013, 249.862, -87.151, 207.527, 43.432]
60.815

[-57.016, 175.989, 132.392, 217.191, 102.575, 192.182, 214.864, 30.191, 138.432]

127.422