3. A cohort study of smoking and bladder cancer was conducted in a small island population. There were a total of 6000 people on the island. Twenty-four hundred were smokers and 3600 were not. Three hundred of the smokers developed bladder cancer. Sixty of the non-smokers developed bladder cancer.

1. Which measure of comparison would you use to describe the relative effect of smoking on the risk of bladder cancer?

1. What is the formula for this measure of comparison?

1. Calculate this measure of comparison using the given data.