Logical reasoning PrepTest 104 · Section 1 · Question 3

Question prompt

In Yasukawa's month–long study Remaining source text redacted.
Why the credited answer is right

Credited answer: D

The notes below walk through why it fits the stem and how to eliminate the rest.

Argument or Facts

Argument

Valid or Flawed

Flawed

Question Type

Must Be True Questions

Stimulus Summary

Phenomenon - Over a month, the small bird survival rate was higher than the large bird survival rate
Yasukawa explanation - Size determines survival
Author’s explanation - Smaller birds are generally younger than larger ones (i.e., it’s age, not size)
Conclusion - Yasukawa’s explanation is probably wrong

Answer Anticipation

It’s rare enough to see a Must be True question with an argument, let alone one with a rebuttal structure! When dealing with an argument in a Must be True question, we treat all the statements as true - as we do in all Must be True questions. This means that we accept that Yasukawa believes size is related to survival, but that this is probably wrong, as we accept the author’s assessment of that argument.
That said, it does fall into a common pattern - Phenomenon/Explanation. The phenomenon relates to survival rates for birds of different sizes, and the dueling explanations are that the survival rate is related to size, and to age.
It’s unclear how this is going to play into the correct answer! Normally, we’d fill in an inference, or look for statements that tend to lead to inferences (strong statements, conditionals, comparisons, causality). We don’t really have that here, so let’s use our framing of this stimulus to help analyze the answers. We’re flying a bit blind!

Answer choices

  1. A
    Among the blackbirds that Remaining source text redacted.
    Why choice A is not credited
    This answer would invalidate the author’s rebuttal, and there’s no sign that she’s wrong.

  2. B
    Larger blackbirds of a Remaining source text redacted.
    Why choice B is not credited
    This lines up with Yasukawa’s explanation, but the argument provides a reason to call that explanation into question.

  3. C
    Among blackbirds of the Remaining source text redacted.
    Why choice C is not credited
    The author argues that age is an explanation for the survival rates, and this answer cuts against that.

  4. D
    Among blackbirds of the Remaining source text redacted.
    Why choice D matches the stem
    The author argues that Yasukawa’s explanation - that size is a determinant of survival odds - is “probably mistaken.” That means that it’s possible that size doesn’t determine survival odds, other things equal, as this answer states. This answer reflects the author’s conclusion, which the stem tells us to accept as true, so this is the correct answer.

  5. E
    With a larger sample Remaining source text redacted.
    Why choice E is not credited
    There’s no way to know what would happen with a larger sample, so we can’t infer this answer.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 11%
  2. B 8%
  3. C 8%
  4. D Credited 70%
  5. E 2%

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