Question

Suppose the incidence rate of myocardial infarction (MI)
was 5 per 1000 among 45- to 54-year-old men in 2000.
To look at changes in incidence over time, 5000 men in this
age group were followed for 1 year starting in 2010. Fifteen
new cases of MI were found

7.12 Using the critical-value method with α = .05, test the
hypothesis that incidence rates of MI changed from 2000
to 2010.
7.13 Report a p-value to correspond to your answer to
Problem 7.12.
Suppose that 25% of patients with MI in 2000 died within
24 hours. This proportion is called the 24-hour case-fatality
rate.
7.14 Of the 15 new MI cases in the preceding study,
5 died within 24 hours. Test whether the 24-hour casefatality
rate changed from 2000 to 2010.
7.15 Suppose we eventually plan to accumulate 50 MI
cases during the period 2010–2015. Assume that the
24-hour case-fatality rate is truly 20% during this period.
How much power would such a study have in distinguishing
between case-fatality rates in 2000 and 2010–2015 if a
two-sided test with significance level .05 is planned?
7.16 How large a sample is needed in Problem 7.15 to
achieve 90% power?

Answer 1