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I know it's common for beginners to (mistakenly) think there are multiple correct answers to a question, but I just can't see how there's only one correct answer in this case. Any input would be greatly appreciated.
Question: PT114.S2.Q9
Complete stimulus: During the three months before and the three months after a major earthquake in California, students at a college there happened to be keeping a record of their dreams. After experiencing the earthquake, half of the students reported dreaming about earthquakes. During the same six months, a group of college students in Ontario who had never experienced an earthquake also recorded their dreams. Almost none of the students in Ontario reported dreaming about earthquakes. So it is clear that experiencing an earthquake can cause people to dream about earthquakes.
Complete question stem: Which one of the following, if true, most strengthens the argument?
Complete answer choices:
A: Before the California earthquake, no more of the students in California than of those in Ontario recorded dreams about earthquakes.
B: The students in California were members of a class studying dreams and dream recollection, but the students in Ontario were not.
C: Before they started keeping records of their dreams, many of the students in California had experienced at least one earthquake.
D: The students in Ontario reported having more dreams overall, per student, than the students in California did.
E: The students in Ontario who reported having dreams about earthquakes recorded the dreams as having occurred after the California earthquake.
Answer choice A is marked as correct, and answer choice D is marked as incorrect.
My reasoning: Answer choice D strengthens the argument by eliminating an alternate explanation: California students had more dreams about earthquakes because they have more dreams in general. Therefore, an earthquake occurring in California would not be the reason why half of the students reported having dreams about earthquakes.
Thanks for the help!
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3 comments
I can see why you thought D was correct, I was initially tripped up on it too :) But simplifying the stimulus:
After the earthquake, Cali students dreamed about earthquakes. In this same time, no Ontario peeps dreamed about earthquakes. The author then claim experiencing earthquake make you dream about it.
Does knowing how many times they were dreaming help you? If Cali students dream once a week, and that dream involve an earthquake, vs Ontario students dreaming 7 times a week ... you don't get any useful observations! The main point is still that Ontario students didn't dream about earthquakes!
I read A as the only correct answer, because it's saying both groups were the same before the earthquake, then the earthquake happened, and we saw a change in the California group! I hope this helps, and if you're curious - this is the exact same methodology as a quasi-experimental study! Hit me up if that piqued your interest haha.
One trick that has helped me a lot in both strengthen and weaken question is to build a bridge between the premise (experiencing an earthquake) and conclusion (dreaming about earthquakes). Once you label the premise and conclusion, you can fill in the gap to strengthen the argument, or break the bridge to weaken the argument. In this case to strengthen it, you could show how experiencing an earthquake has lead to dreaming about earthquakes, because before experiencing earthquakes no one dreamt about earthquakes. An example to weaken it would be if students were having dreams about earthquakes before they experienced it, to show that the earthquake didn't cause the dreams. Hope this helps!
I think that establishing a causal relationship between earthquakes and earthquake dreams, like A does, is a much stronger strengthener than eliminating a sort of unlikely alternative explanation. Sometimes the other 4 answer choices aren't wrong just because they're factually or logically incorrect, or even bc they weaken or do nothing vs strengthen... sometimes they're just noticeably flimsier strengthen/weakens. The causal relationship is the core/conclusion of the argument, therefore the thing that establishes it is the best strengthener. :)