In the article “Aspirin and the treatment of heart failure in the elderly” published in Archives of Internal Medicine (Krumholz et al., 2001), the authors reported the summarized data given in Table 7.31 on the number of deaths after one year for 456 patients prescribed aspirin and 654 patients not prescribed aspirin at discharge after hospitalization for heart failure. Use the data in Table 7.31 to answer the following questions.

(a) Does the data in Table 7.31 support the use of a chi-squared test of independence?

(b) Test the hypothesis that survival status is independent whether or not aspirin is prescribed at discharge at the ???? = 0.05 level.

(c) Compute a 95% confidence interval for the odds ratio.

(d) Compute a 95% confidence interval for the percentage of patients who were prescribed aspirin at discharge that die within one year of discharge.

(e) Compute a 95% confidence interval for the percentage of patients who were not prescribed aspirin at discharge that die within one year of discharge.