New Scientist (Mestel, 12 November 1994) reported a study in which psychiatrist Donald Black used the drug fluvoxamine to treat compulsive shoppers: In Black’s study, patients take the drug for eight weeks, and the effect on their shopping urges is monitored. Then the patients are taken off the drug and watched for another month. In the seven patients examined so far, the results are clear and dramatic, says Black: the urge to shop and the time spent shopping decrease markedly. When the patient stops taking the drug, however, the symptoms slowly return (p. 7).
a. Explain why it would have been preferable to have a double-blind study, in which shoppers were randomly assigned to take fluvoxamine or a placebo.
b. What are the null and alternative hypotheses for this research?
c. Can you make a conclusion about the hypotheses in part (b) on the basis of this report? Explain.