Logical reasoning PrepTest 146 · Section 1 · Question 5

Incorrect. So tempting! However, the rebuttal doesn't highlight that the sample is unrepresentative, but rather that the responses might not be honest.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Methods of Reasoning

Stimulus Summary:
A study showed that twice as many 50yo reported giving blood as 20yo. The study concluded that 50yo are more altruistic, but people don't like admitting they're selfish, so there's reason to think the results are off.

Answer Anticipation:
First, the question type here. It would be easy to think this is a Weaken or Errors in Reasoning question because it talks about calling an argument into question. However, it states that the reasoning above calls an argument into question, so we're being tasked with describing how that reasoning works. That's a Methods of Reasoning question.

Now, to approaching this question! We knew from the stem that this question would feature an opposing argument, so we should have been prepared for it and the pivot. Here, the opposing argument bases its conclusion on a study, and if you started to think about a sampling flaw, we're happy! However, in this case, we're not the ones who are going to analyze the logic of this opposing point—we're going to describe how the argument itself calls that logic into question. So good instincts, but they'll be less useful here.

Reading through, we see the pivot almost _ of the way through the argument, stating that there is reason for skepticism—but of the argument, the conclusion, the premises, or a mix? Well, that final statement tells us—people are hesitant to admit that they are acting in an a- or anti-social manner. How does that work against the opposing viewpoint? The study asked people if they donated blood—so this premise is suggesting some of them lied about it, thus explaining why one group seemed more altruistic than another. Whether this rebuttal is itself flawed is out of the scope of our work here, since we have our description of its method of reasoning!

(That said, it's flawed; it's very, very flawed. Why wouldn't this explanation apply equally to both groups?)

Answer Explanation:
This answer correctly highlights the way that the argument undermines the opposing point. That viewpoint explains the higher reporting of blood donation among the older group as being explained by altruism; the rebuttal explains it by raising the possibility that the older group lied about their blood donation rate. (Note that this definitely isn't the only way that a correct answer could have been phrased—stay flexible in Methods of Reasoning answers!)

Key Takeaway:
First, don't do work that you don't have to do. Here, the question asked for the method of reasoning of the rebuttal—there was no need to analyze the logic of either that rebuttal or the opposing point.

Second, these abstract-answer questions (mainly Methods of Reasoning and Argument Structure) frequently take a different tack than your anticipation. Stay flexible and consider any answer choice that aligns with your anticipation!

Incorrect. The rebuttal has to do with admissions, not observation.

Incorrect. There's no ad hominem attack against the researchers—the rebuttal doesn't address them at all.

Incorrect. "Many people" do not a "specific" counterexample make. (Yes, that's very bad grammar.)