LSAT 142 – Section 1 – Question 18

LSAT 142 - Section 1 - Question 18

December 2014

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT142 S1 Q18
+LR
Flaw or descriptive weakening +Flaw
Causal Reasoning +CausR
A
62%
165
B
11%
156
C
4%
157
D
2%
159
E
20%
164
143
157
171
 +Harder 145.991 +SubsectionMedium

Medical researcher: A survey of more than 1 million adults found that there was a greater frequency of illness among people who regularly slept at least 8 hours a night than among people who slept significantly less. This shows that mild sleep deprivation is not unhealthy and, in fact, probably bolsters the body’s defenses against illness.

Summarize Argument

The researcher concludes that mild sleep deprivation is not unhealthy and probably strengthens the immune system. She supports this with a survey which found that people who sleep at least 8 hours a night are sick more often than people who sleep significantly less.

Identify and Describe Flaw

This is the cookie-cutter flaw of assuming that correlation proves causation. Here, the researcher points out a correlation between getting less sleep and getting sick less often, then concludes that sleep deprivation causes people to get sick less often. However, she ignores the possibility that another factor, like exercise or a healthy diet, might cause people to both need less sleep and to have a stronger immune system.

A
fails to address the possibility that an observed correlation between two phenomena is due to another factor that causally contributes to both phenomena

The researcher fails to address the possibility that the correlation between sleep deprivation and getting sick less often is due to another factor— like diet or exercise— that causally contributes to both.

B
fails to consider that even if a given factor causally contributes to the occurrence of a given phenomenon, it may not be the only factor affecting the occurrence of that phenomenon

The researcher never assumes that sleep deprivation is the only thing that prevents illness. Instead, she fails to consider that a given factor (sleep deprivation) might not causally contribute to the occurrence of a given phenomenon at all.

C
concludes, from the claim that a certain phenomenon occurs and the claim that a certain condition is sufficient for that phenomenon to occur, that the condition also exists

The researcher concludes that sleep deprivation strengthens the immune system from the claim that the two are correlated. She does not conclude that sleep deprivation exists from the claim that it is sufficient for a strengthened immune system.

D
takes for granted that there will be an observable correlation between two phenomena if either of those phenomena causally contributes to the other

Actually, the researcher takes for granted (or assumes) that one phenomenon causally contributes to the other since there is an observable correlation between the two phenomena.

E
fails to consider that even if a specific negative consequence is not associated with a given phenomenon, that phenomenon may have other negative consequences

The researcher doesn't claim that sleep deprivation is not associated with illness, just that it's associated less frequently than sleeping 8 hours. She also never assumes that sleep deprivation has no other negative consequences.

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LSAT PrepTest 142 Explanations

Section 1 - Logical Reasoning

Section 2 - Logical Reasoning

Section 3 - Reading Comprehension

Section 4 - Logical Reasoning

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