Exercise 2.25 on page 57 introduces a study investigating whether smoking might negatively effect a person€™s ability to become pregnant. The study collected data on 678 women who had gone off birth control with the intention of becoming pregnant. Smokers were defined as those who smoked at least one cigarette a day prior to pregnancy. We are interested in the pregnancy rate during the first cycle off birth control. The results are summarized inTable C.7.

(a) Find a 95% confidence interval for the difference in proportion of women who get pregnant between smokers and non-smokers. From the confidence interval, can we conclude that one group has a significantly higher pregnancy success rate than the other? Explain.
(b) Conduct a hypothesis test to determine if the pregnancy success rates of smokers and nonsmokers are significantly different. Does the result agree with the conclusion in part (a)?
(c) Can we conclude that smoking causes women to have less success when trying to become pregnant during the first cycle? Explain.

Exercise 2.25 on page 57

Studies have concluded that smoking while pregnant can have negative consequences, but could smoking also negatively affect one€™s ability to become pregnant? A study collected data on 678 women who had gone off birth control with the intention of becoming pregnant. Smokers were defined as those who smoked at least one cigarette a day prior to pregnancy. We are interested in the pregnancy rate during the first cycle off birth control. The results are summarized in Table 2.11.

Transcribed Image Text:

Non-smoker Smoker Total 244 434 Pregnant Not pregnant Total 38 97 206 337 135 543 678 Smoker Non-smoker Total Pregnant 206 Not pregnant Total 38 97 135 244 434 678 337 543