A cohort study of smoking and bladder cancer was conducted in a small island population over 10 years. There were a total of 2000 people on the island, 400 were smokers and 1600 were not. Of the smokers, 50 developed bladder cancer. Of the non-smokers, 20 developed bladder cancer.
Which measure of comparison would you use to describe the absolute effect of smoking on the risk of bladder cancer among the total island population? Calculate this measure of comparison using the given data. State the meaning of your answer in one sentence
