An investigator wants to test whether exposure to second-hand smoke before 1 year of life is associated with development of childhood asthma (defined as asthma diagnosed before 5 years of age).Give two possible study designs and indicate the pros and cons of each.Then, provide your recommendation for the most efficient design.

A study is run to estimate the incidence of atrial fibrillation (AF) in men and women over the age of 60.Development of atrial fibrillation was monitored over a 10 year follow-up period.The data are summarized below.

Developed AF

Did not Develop AF

Men

120

6453

Women

86

7074

1. Compute the cumulative incidence of AF in men and in women
2. Compute the relative risk of AF incidence comparing men to women
3. Compute the odds ratio of AF incidence comparing men and women