Page 207 Exercise I.10: Gallup polls are described on the Gallup website, www.gallup.com. Exercise I.10 is from “Nearly half of smartphone users can’t imagine life without it,” Gallup press release dated July 13, 2015.

Page 207 Exercise I.11: Exercise I.11 is from “Americans say Caitlyn Jenner’s public transition will grow acceptance of transgender persons,” NBC News Online Survey press release dated June 9, 2015.

Page 208 Exercise I.12: Exercise I.12 is from “Johnny Carson tops list as all-time king of late night, Quinnipiac University national poll finds; Jimmy Fallon tops list of current hosts,” Quinnipiac University poll press release dated June 2, 2015.

Page 208 Exercise I.16, Exercise I.17, Exercise I.18 and Exercise I.19: Paulina Salminen et al., “Antibiotic therapy vs appendectomy for treatment of uncomplicated acute appendicitis: the APPAC randomized clinical trial,” Journal of the American Medical Association, 313 (2015), pp. 2340–2348.