In 1951, the investigators mailed out a questionnaire to all British doctors to provide information about their smoking habits, and 34,440 responded. With few exceptions, all subjects were followed for 20 years. Death from lung cancer was the outcome of interest. A death was due to lung cancer if it was listed as the underlying cause of death. The age-adjusted annual death rate from lung cancer was 83 per 100,000 among smokers and 10 per 100,000 among non-smokers.

1. What kind of study is this? (Be specific.) (1 point)

1. Calculate the appropriate measure of association and the 95% confidence interval between smoking habit and risk of death from lung cancer.(4 points)

Interpret your result (2 points).