Mean is the same as average. Adding up all the amounts then dividing it by the number of amounts. In this case, we add up all the snowfall amounts and then we divide it by 10 ( the count or number of snowfall amounts). In equation, (13+19+16+23+11+18+14+26+13+16) / 10 = 16.9
The price that does not belong is 16,18.40. You do this by finding the percent gratuity, which is 15%. All the other values have 15% gratuity except the $16.
