Does lovastatin (a cholesterol-lowering drug) minimize the risk of heart attack? In the Texas study, researchers gave lovastatin to 2,325 people and the inactive substitute to 2,081 people (average age 58). After five years, 57 of lovastatin group had suffered heart attack, compared with 97 for the inactive pill.
(a) State appropriate hypotheses.
(b) Obtain test statistic and p-value. Interpret results at α = .01.
(c) Is normality assured?
(d) Is the difference large enough to be significant?
(e) What else would medical researchers require to know before prescribing this drug widely?