PrepTest 106
[lcid:3522] Prep Test 106 LSAT — Logical Reasoning — S3
Logical reasoning
Question prompt
A rise in the
Remaining source text redacted.
Why the credited answer is right
Credited answer: C
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
Weaken Questions
Stimulus Summary
Correlation - Increase in percentage of 18yo recruited into army and increase in high school drop-out rate
All 18yo are either grads or dropouts
Conclusion - Recruitment rates for 18yo rely on dropouts
Answer Anticipation
Weaken questions tend to have Correlation/Causation flaws, so you should always be on the lookout for language suggesting that flaw in this question type. And this stimulus talks about correlations all over the place! However, the conclusion isn’t clearly causal, so we need to dig a bit deeper.
Let’s start with some basic questions - what’s correlated, and does the argument assume that one causes the other?
The correlation is between recruitment rates among 18yo and the dropout rate - they both went up around the same time. Does the argument assume that the recruitment rate caused the dropout rate, or vice versa? It does. While the conclusion states that the recruitment rate depends substantially on the dropout rate, that’s assuming that the dropout rate drives the recruitment rate. As such, it’s assuming, essentially, that an increase in the dropout rate will cause an increase in the recruitment rate for 18yo. It’s not a perfectly causal argument, but it’s close enough that we can look for the standard answers:
Identify an alternative cause Counterexamples (cause without effect; effect without cause) Reverse causality (which makes sense here - maybe an increase in recruitment led 18yo to drop out because, say, the army was paying very well)
Let’s find one of these answers.
Answer choices
-
AA larger number of Remaining source text redacted.
Why choice A is not credited
This answer doesn’t carry enough force to weaken the argument. An increase in the number of graduates being recruited is compatible with an increase in the percentage of dropouts being recruited if the total number of recruits went way up. -
BMany of the high–technology Remaining source text redacted.
Why choice B is not credited
First, this answer isn’t about only 18yo, as the conclusion is. Also, similar to (A), this answer doesn’t have enough force to weaken the argument. Even though the armed services have some jobs that require a high school diploma, those could be few and far between, allowing for more dropouts to be hired. -
CBetween 1980 and 1986 Remaining source text redacted.
Why choice C matches the stem
This answer establishes that what is true of the dropouts is also true of the graduates, weakening the meaningfulness of that correlation and thus weakening the argument. -
DPersonnel of the republic's Remaining source text redacted.
Why choice D is not credited
First, this answer isn’t about only 18yo, as the conclusion is. Second, this answer is about what happens after recruitment - once they’re already personnel, they’re encouraged to go back and finish their education. It’s off the timeline of the argument, so it’s out of scope. -
EThe proportion of recruits Remaining source text redacted.
Why choice E is not credited
The argument is about 18yo, and people who have at least two years of college would be older than that, so this answer is out of scope.
What this tests
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