Quit Smoking: Previous studies suggest that use of
nicotine-replacement therapies and antidepressants can help people
stop smoking. The New England Journal of Medicine published the
results of a double-blind, placebo-controlled experiment to study
the effect of nicotine patches and the antidepressant bupropion on
quitting smoking. The target for quitting smoking was the 8th day
of the experiment. In this experiment researchers randomly assigned
smokers to treatments. Of the 162 smokers taking a placebo, 28
stopped smoking by the 8th day. Of the 272 smokers taking only the
antidepressant buproprion, 82 stopped smoking by the 8th day.
Calculate the 99% confidence interval to estimate the treatment
effect of buproprion (placebo-treatment). (The standard error is
about 0.0407. Use critical value z = 2.576.)