LSAT Question Stem

Which one of the following, if true, most strengthens the argument? 

Logical Reasoning Question Type

This is a Strengthen question. 

Correct Answer

The correct answer to this question is A. 

LSAT Question Complete Explanation

The passage presents an argument that experiencing an earthquake can cause people to dream about earthquakes. The argument is based on a comparison between students in California who experienced a major earthquake and students in Ontario who have never experienced an earthquake. After the earthquake, half of the students in California reported dreaming about earthquakes, while almost none of the students in Ontario did. The conclusion is that experiencing an earthquake can cause people to dream about earthquakes.

The structure of the argument is as follows:

1. Premise: After the earthquake, half of the students in California reported dreaming about earthquakes.

2. Premise: Almost none of the students in Ontario, who have never experienced an earthquake, reported dreaming about earthquakes.

3. Conclusion: Experiencing an earthquake can cause people to dream about earthquakes.

An "Evaluate" question for this argument would be: "What were the rates of dreaming about earthquakes among the students in California before the earthquake?"

The question type is Strengthen, which asks us to find the answer choice that, if true, most strengthens the argument.

Answer choice A is the correct answer because it provides information about the rates of dreaming about earthquakes among the students in California before the earthquake. It states that before the earthquake, no more of the students in California than of those in Ontario recorded dreams about earthquakes. This strengthens the argument because it suggests that the increase in dreams about earthquakes among the California students after the earthquake is likely due to their experience of the earthquake, rather than other factors.

Answer choice B is incorrect because it introduces irrelevant information about the students' class subjects. The argument is about the causal relationship between experiencing an earthquake and dreaming about earthquakes, not about the students' academic interests.

Answer choice C is incorrect because it does not provide information about the rates of dreaming about earthquakes among the students in California before the earthquake. It simply tells us that many of the students in California had experienced at least one earthquake before they started keeping records of their dreams.

Answer choice D is incorrect because it does not address the causal relationship between experiencing an earthquake and dreaming about earthquakes. The number of dreams overall, per student, is not relevant to the argument.

Answer choice E is incorrect because it does not strengthen the argument. It suggests that the students in Ontario who reported having dreams about earthquakes recorded the dreams as having occurred after the California earthquake. This information is not relevant to the causal relationship between experiencing an earthquake and dreaming about earthquakes, as the students in Ontario have never experienced an earthquake.

In conclusion, answer choice A is the correct answer because it provides information about the rates of dreaming about earthquakes among the students in California before the earthquake, which strengthens the argument that experiencing an earthquake can cause people to dream about earthquakes.