XrA14-15 Researchers at the University of Washington conducted an experiment to determine whether the herbal remedy Echinacea is effective in treating children’s colds and other respiratory infection (National Post, December 3, 2003). A sample of 524 children was recruited.

Half the sample treated their colds with Echinacea, and the other half was given a placebo. For each infection, the duration of the colds (in days) were measured and recorded. Can we conclude that Echinacea is effective?

A14.16 XrA14-16 The marketing manager of a large ski resort wants to advertise that his ski resort has the shortest lift lines of any resort in the area. To avoid the possibility of a false advertising liability suit, he collects data on the times skiers wait in line at his resort and at each of two competing resorts on each of 14 days.

a. Can he conclude that there are differences in waiting times between the three resorts?

b. What are the required conditions for these techniques?

c. How would you check to determine that the required conditions are satisfied?