Brent et al. (1993) carried out a study to investigate the possible association between firearms in the home and adolescent suicide. How big is the risk? They obtained information on 67 adolescent suicide victims, 70% of whom had died by firearms. The researchers compared this group to a control sample of 67 adolescents of similar race, age, gender, childhood behavior scores, and socioeconomic status and living in the same cities. They found that in 51 of the suicide cases, guns were kept in the home, whereas this was true of 16 of the controls.

a. Graph the association between suicide and the presence of guns in the home. What trend is suggested?

b. What is the estimated odds ratio of suicide with guns in the home, compared to homes without guns?

c. Provide a 95% confidence interval for the population odds ratio.

d. Under what circumstances can this estimate of the odds ratio be used to approximate the relative risk of suicide with guns in the home, compared to homes without guns?