A two-sample proportion example
In the past decade intensive antismoking campaigns have been sponsored
by both federal and private agencies. Suppose that, in order to
determine the success of such campaigns, the American Cancer
Society randomly sampled 1,500 adults in 1989 and found that 551 were
smokers, and then sampled 2,000 adults in 1999 to find that 652 were
smokers.
- Construct the 95% confidence interval for the change in
proportion of smokers over the 10-year period.
- Does the data indicate that the fraction of smokers decreased
over this 10-year period?
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