Can the drug hydroxyurea reduce the severe pain caused by sickle cell disease? A study by the National Institute of Health gave the drug to 150 sickle cell sufferers and a placebo to another 150. The researchers counted the number of episodes of pain reported by each subject. What are the subjects, the factor, the treatments, and the response variable?
Solution: The subjects are the 300 individuals that took part of the experiment. The factor is the type of drug; the treatments are hydroxyurea and placebo. The response variable is the number of episodes of pain reported by each subject.