Question

A vaccine trial reports a 60% reduction in disease incidence in the trial population. Which is the safest inference?

• A. The vaccine is effective in similar populations under similar conditions.
• B. The vaccine eliminates the disease everywhere.
• C. No further studies are needed.
• D. Effectiveness is identical across all age groups.

Hint:

For scientific inference questions, generalize cautiously; trial results apply reliably only to similar populations under similar conditions.

Answer 1

The Correct Option is A

Step 1: Understand the claim — A trial shows a 60% reduction in disease incidence.
Step 2: Safest inference — The result can be generalized only to similar populations and conditions, not universally.
Step 3: Evaluate options — (b), (c), (d) overgeneralize or ignore need for further studies.
Step 4: Conclusion — Option (a) is correct.