“In a survey at a school, students who ate breakfast scored higher, on average, in morning tests than students who skipped breakfast. So, eating breakfast improves students’ test scores.”
Which of the following, if true, most weakens the argument?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → The students who ate breakfast also, on average, slept longer and studied more hours than those who skipped it.
An argument that one thing causes another is weakened by a fact that shows some other cause could explain the same result. If the breakfast-eaters also slept longer and studied more, their higher scores may come from the extra sleep and study, not from breakfast, so the argument loses its force.
Why the other options are incorrect
Option (1) Breakfast gives the body energy after the night’s fast. — Incorrect. This gives a reason why breakfast could help, so it supports the argument.
Option (2) Both groups of students took the same morning tests. — Incorrect. This rules out the objection that one group had easier tests, so it supports the comparison.
Option (4) Many students in the school like to eat fruit at breakfast. — Incorrect. What students like to eat says nothing about whether breakfast raises scores.