“In a school, the students who joined the music club scored higher marks in mathematics, on average, than the students who did not join it. So, joining the music club improves students’ marks in mathematics.”
Which of the following, if true, most weakens the argument?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Most of the students who joined the music club were already scoring high marks in mathematics before they joined.
An argument that one thing causes another is weakened by a fact that shows some other cause could explain the same result. If the club members were already good at mathematics before joining, their higher marks came first and cannot be the result of the club, so the argument loses its force.
Why the other options are incorrect
Option (1) Music is taught in many schools across the country. — Incorrect. What other schools teach says nothing about whether this club raised marks.
Option (3) The music club meets twice a week after school hours. — Incorrect. How often the club meets does not show whether it raised marks.
Option (4) The marks of both groups were taken from the same mathematics examination. — Incorrect. This rules out the objection that the two groups took different examinations, so it supports the comparison.