Smoker Non-smoker Total Pregnant 38 206 244 Not Pregnant 97 337 434 Total 135 543 678 3. A study looked at the relationship between smoking and getting 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. Summary results are in the two-way table on the right. (a) [2 pts] Identify the (i) explanatory and (ii) response variable in this scenario. (b) [2 pts] Is this an experiment or an observational study? Explain how you know, using ideas taught in this class about what distinguishes an experiment from an observational study. (c) [2 pts] Compute the proportion (i) of smokers in this study that became pregnant and (ii) non-smokers that became pregnant. Round your answer to two decimals or leave your answer as an un-simplified fraction. (d) [2 pts] Can the data from this study be used to determine whether smoking changes someone's ability to get pregnant? Explain your answer, using ideas learned from this class about the types of conclusions that can be reached from different types of studies.