A prospective cohort study was conducted to investigate the association between smoking at study entry and cardiovascular death during the follow-up period. Participants, categorized at the start of the study as smokers (exposed - yes) and non- smokers (exposed - no), were followed over time to see if they ultimately died from a cardiovascular cause. The data are summarized in the following table:

(a) Compare the proportion of those who died from a cardiovascular cause between the two groups (where group is based on smoking exposure status) using a 99% confidence interval. Provide a written conclusion of the interval.

(b) Compare the proportion of those who died from a cardiovascular cause between the two groups using a hypothesis test with significance level .05. Provide a written conclusion of the test.

(c) Generate a relative risk point estimate. Also, calculate a relative risk interval estimate using a 98% confidence interval. Provide a written conclusion of the interval.

Exposed? Yes No Death from cardiovascular cause? Yes 35 18 No 1586 2100