Question 315529
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 the lovastatin group had suffered a heart attack, compared with 97 for the inactive pill. 
(a) State the appropriate hypotheses.
Ho: p(placebo)-P(lova) = 0
Ha: p(placebo)-p(lova) > 0 
(b) Obtain a test statistic and p-value. Interpret
the results at α = .01
I ran a two-proportion z-test and got the following.
Test statistic: z = 3.987
p-value: 0.00003348....
Conclusion: Since the p-value is less than 1% reject Ho.
Less than 0.003348% of test results could have provided stronger 
evidence for rejecting Ho.
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(c) Is normality assured?
I'll leave that to you.
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(d) Is the difference large enough to be important?
Yes it is very large as seen in the very small p-value.
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(e) What else would medical researchers need to know before prescribing this drug widely?
I'll leave that to you.
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Cheers,
Stan H.