LSAT 157 – Section 3 – Question 25

LSAT 157 - Section 3 - Question 25

June 2020

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT157 S3 Q25
+LR
Weaken +Weak
A
35%
161
B
6%
156
C
7%
151
D
41%
158
E
12%
153
150
172
180
 +Hardest 145.111 +SubsectionEasier

To test the claim that vitamin C is effective in treating acne, scientists administered it to one group of subjects and a placebo to a control group. The group receiving vitamin C had less severe acne during the study than did the control group. It was subsequently discovered, however, that half of the subjects in each group knew which kind of pill they were given. Among those who could not tell, no difference in the severity of acne was found between the two groups. Therefore, we can tentatively conclude that vitamin C has no real benefit in reducing the severity of acne.

Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that vitamin C does not help reduce the severity of acne. This is based on a study showing no difference in the severity of acne between a group given vitamin C and a control group given a placebo.

Notable Assumptions
The argument assumes that there were no differences between the vitamin C group and the control group that could have made the vitamin C group’s acne more severe, thus masking the beneficial effect of vitamin C. The argument also assumes that before the study began, the vitamin C group did not start with more severe acne than the control group, which is another way beneficial effects of vitamin C could have been masked.

A
The subjects who were given vitamin C had a history of suffering from more severe acne than did the subjects receiving a placebo.
This explains how the two groups might end up with the same severity of acne even if vitamin C does help to reduce severity. Vitamin C may have reduced the severity down to the same level as that of the placebo group.
B
None of the subjects who were given vitamin C took additional doses of vitamin C on their own.
If this has any impact at all, this might strengthen the argument by showing that the vitamin C group didn’t take more vitamin C than they were supposed to. Learning that study subjects didn’t do things they weren’t supposed to doesn’t undermine an argument based on a study.
C
During the study, the severity of the subjects’ acne was lower than the national average.
How the subjects’ acne compared to the national average is irrelevant because we’re comparing the severity of the vitamin C group’s acne to the severity of the placebo group’s.
D
Some of the subjects who were given placebos consumed foods during the study that are naturally rich in vitamin C.
We have no reason to think this isn’t equally true of the vitamin C group. In addition, “some” subjects could just be a single person, which would not necessarily affect the overall average results observed in the placebo group.
E
Some of the subjects who knew their pills were placebos did not actually take the pills they were given.
The conclusion isn’t based on data about the people that knew they got the placebo or the vitamin C. It’s based on data about the people that didn’t know whether they got the placebo or the vitamin C.

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LSAT PrepTest 157 Explanations

Section 1 - Reading Comprehension

Section 2 - Logical Reasoning

Section 3 - Logical Reasoning

Section 4 - Reading Comprehension

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