Diver Dan enjoys scuba diving. He dives to 34 feet below the surface of a lake. His friend "Jump in Jeff" dives to 40 feet below the surface, but then descends 20 feet. What is the vertical distance between Dan and Jeff?

According to a study conducted in 2015, 18% of shoppers said that they prefer to buy generic instead of name-brand products. suppose that in a recent sample of 1500 shoppers, 315 stated that they prefer to buy generic instead of name-brand products. at a 5% significance level, can you conclude that the proportion of all shoppers who currently prefer to buy generic instead of name-brand products is higher than .18? use both the p-value and the critical-value approaches.