Gomer decides to spend an hour playing basketball rather than studying. his opportunity cost of playing basketball is:

Which statement below best describes george waring's approach to solving the problems of water-borne illness? a. waring is going with his "gut," because he believes that instincts and emotions are the best guides for action. b. waring efficiently and thoroughly lays out the case for why the problems are too large and overwhelming to be solved: people should just move out of cities back to their farms. c. waring has gathered the testimonies of people who live in densely populated areas in order to learn how they themselves have solved their problems. d. waring exhibits the industrial age's increased respect for and reliance on science and the scientific method.

True or false: a fitted model with more predictors will necessarily have a lower training set error than a model with fewer predictors.

Google started as one of many internet search engines, amazon started as an online book seller, and ebay began as a site where people could sell used personal items in auctions. these firms have grown to be so large and dominant that they are facing antitrust scrutiny from competition regulators in the us and elsewhere. did these online giants grow by fairly beating competition, or did they use unfair advantages? are there any clouds on the horizon for these firms -- could they face diseconomies of scale or diseconomies of scope as they continue to grow? if so, what factors may limit their continued growth?