Researchers selected 1,000 adults at random from a country's population and recorded each adult's diet and blood pressure. Adults who ate fish more often had lower average blood pressure. Which conclusion is best supported?

Question

Accepted Answer

A. Among adults in the country, eating fish more often is associated with lower blood pressure.. Random SELECTION means the result generalises to the country's adults. But nobody was assigned a diet — people chose their own — so the study shows an association, not a cause.

Answer

B. Eating fish more often causes lower blood pressure in adults in the country. — Causation needs random assignment to diets. Here adults chose their own diets, so something else (exercise, income, other foods) could explain the difference.

Answer

C. The association holds only for the 1,000 adults studied and cannot be generalised to the country. — Because the sample was selected at random from the country's adults, the association DOES generalise to that population.

Answer

D. Eating fish has no effect on blood pressure. — The study found a clear association; it can't rule fish in as a cause, but it certainly doesn't show 'no effect'.

Problem-Solving and Data Analysis practice question

Answer: A. Among adults in the country, eating fish more often is associated with lower blood pressure.

Why the other answers are wrong

More Problem-Solving and Data Analysis questions