Test the significant difference between the two population proportions.
Does lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack? In a Texas study, researchers gave lovastatin to 2,325 people and an inactive substitute to 2,081 people (average age 58). After 5 years, 57 of lovastatin group had suffered a heart attack, compared with 97 for the inactive pill.
a) State appropriate hypotheses.
b) Obtain a test statistic and p-value. Interpret the results at = .01.
c) Is normality assured?
d) Is the difference large sufficient to be important?
e) What else would medical researchers require to know before prescribing this drug widely?