Problem
Vitamin C for ultramarathon runners. An ultramarathon, as you might guess, is a footrace longer than the 26.2 miles of a marathon. Runners commonly develop respiratory infections after an ultramarathon. Will taking 600 milligrams of vitamin C daily reduce these infections? Researchers randomly assigned ultramarathon runners to receive either vitamin C or a placebo. Separately, they also randomly assigned these treatments to a group of nonrunners the same age as the runners. All subjects were watched for 14 days after the big race to see if infections developed.27
(a) What is the name for this experimental design?
(b) Use a diagram to outline the design.
(c) The report of the study said:
Sixty-eight percent of the runners in the placebo group reported the development of symptoms of upper res- piratory tract infection after the race; this was sig- ni?cantly more than that reported by the vitamin C- supplemented group (33%).
Explain to someone who knows no statistics why "signi?cantly more" means there is good reason to think that vitamin C works.
The response should include a reference list. Double-space, using Times New Roman 12 pnt font, one-inch margins, and APA style of writing and citations.