Question

ch 9 apparently, according to some studies, men that drive expensive sports cars have lower blood pressure and fewer cardiovascular health problems. we can’t conclude that driving expensive sports cars lowers blood pressure or improves cardiovascular health because the studies described are clearly

○ experiments

○ paired data experiments.

○ stratified experiments.

● observational studies, not experiments—
lurking variables may explain the association.

Explanation:

To determine the correct option, we analyze the study type:

• Experiments involve manipulating variables (e.g., assigning people to drive sports cars or not). Here, the study just observes men who already drive expensive sports cars, so it's not an experiment (eliminating "experiments", "paired data experiments", "stratified experiments").
• Observational studies observe existing groups without manipulation. Lurking variables (e.g., wealth, access to healthcare) could explain the association between driving sports cars and health, so we can't conclude causation. The option "observational studies, not experiments—lurking variables may explain the association" matches this reasoning.

Answer:

D. observational studies, not experiments—lurking variables may explain the association.