In high schools A and B, the proportion of teenagers smoking has been estimated to be .20. The same antismoking educational program will be used again in high school A but a new program is planned for high school B. There is concern whether the new program will be better or worse than the old one or if the results will be about the same.
A study is planned to compare the proportion smoking in the two high schools in June after the programs have been run. The investigators want to take an adequate sample of students and ask them questions concerning their smoking.
They want to make sure that their sample size is large enough so they can detect a difference of .10 in the proportion smoking with α = .05 and β = .10. What size sample should they take in each high school?