Design an experiment. Gary thinks that the way to get a date is to tell a woman about yourself. Greg thinks that getting her to talk about herself works better. You recruit 20 guys who are willing to try either method in conversation and then call the woman a day later to ask for a date. Outline the design of an experiment to decide which method succeeds more often. (Hint: See pages 85–88.)

Exercises I.16 to I.19 are based on an article in the Journal of the American Medical Association that asks if flu vaccine works. The article reports a study of the effectiveness of a nasal spray vaccine called “trivalent LAIV.” Here is part of the article’s summary:

Design Randomized, double-blind, placebo-controlled trial conducted from September 1997 through March 1998.

Participants A total of 4561 healthy, working adults aged 18 to 64 years recruited through health insurance plans, at work sites, and from the general population.

Intervention Participants were randomized 2:1 to receive intranasally administered trivalent LAIV vaccine (n = 3041) or placebo (n = 1520)

in the fall of 1997.

Results Vaccination also led to . . . fewer days of work lost (17.9% reduction for severe febrile illnesses; 28.4% reduction for febrile upper respiratory tract illnesses), and fewer days with health care provider visits (24.8% reduction for severe febrile illnesses; 40.9% reduction for febrile upper respiratory tract illnesses).