well-educated people are less likely to smoke. But what about other nations, where there may be different cultures and/or attitudes towards smoking? In a 1998 study of the relationship between education and smoking in France, a random sample of 334 French men was classified according to their education level (elementary, high school, or university) and their smoking habits (smoker or non-smoker). a) Which of the following makes the most sense as the explanatory variable?

• Whether the relationship between smoking and education level is different in France than in the United States
• Education level
• Whether the subject is a smoker or a non-smoker
• The 334 French men in the sample

b) Which of the following makes the most sense as the response variable?

• Whether the relationship between smoking and education level is different in France than in the United States
• Education level
• Whether the subject is a smoker or a non-smoker
• The 334 French men in the sample

c) Is the explanatory variable categorical or quantitative?

• categorical
• quantitative

d) Is the response variable categorical or quantitative?

• categorical
• quantitative

e) Is this an observational study or an experiment?

• This study is an experiment since each subject was classified into one of the six possible combinations of education level and smoking habits.
• This study is an experiment since it was based on a random sample.
• This study is an observational study since researchers did not assign the men to be smokers or non-smokers, or to one of the education levels.
• This study is a combination of both an experiment and an observational study.