1. Suppose a group of 1000 smokers (who all wanted to give up smoking) were randomly assigned to receive an antidepressant drug or a placebo for six weeks. Of the 455 patients who received the antidepressant drug, 138 were not smoking one year later. Of the 545 patients who received the placebo, 214 were not smoking one year later. Given the null hypothesis $H_0: p_1 = p_2$ and the alternative hypothesis $H_a: p_1 \ne p_2$, conduct a test to see if taking an antidepressant drug can help smokers stop smoking. Use $\alpha = 0.05$

(a)   The rejection region is $|z| >$
(b)   The test statistic is $z =$

The final conclusion is

2. Construct the 95% confidence interval for the difference between the proportions of those who gave up smoking with and without the antidepressant drug.
$< (p_1 - p_2) <$

Which of the following is the correct interpretation for your answer in part 2?

Your overall score for this problem is