Pls explain

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Pls explain

by prachi18oct » Tue May 26, 2015 10:29 am
Guidebook writer: I have visited hotelsthroughout the
country and have noticed that in those built before
1930the quality of the original carpentry work is
generally superior to that in hotels built afterward.
Clearly carpenters working on hotels before 1930
typically worked with more skill, care, and effort than
carpenters who have worked on hotels built
subsequently.
Which of the following, iftrue, most seriously weakens
the guidebook writer's argument?
(A) The quality of original carpentry in hotels is
generally far superior to the quality of original
carpentry in other structures, such as houses
and stores.
(B) Hotels built since 1930 can generally
accommodate more guests than those built
before 1930.
(C) The materials available to carpenters working
before 1930 were not significantly different in
quality from the materials available to
carpenters working after 1930.
(D) The better the quality oforiginal carpentry in a
building, the less likely that building is to fall into
disuse and be demolished.
(E) The average length of apprenticeship for
carpenters has declined significantly since 1930.

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by Ian Stewart » Tue May 26, 2015 10:57 am
This question is testing a logical error known as Survivorship Bias. The writer is discussing hotels built before 1930 that the writer has personally visited, but then draws a conclusion about the quality of workmanship in all hotels built before 1930. But if only the good hotels have survived - if all the bad hotels were demolished - then the writer will get an unfair impression of the quality of older hotels, since he or she is only seeing the best ones. That's why D is the answer here.
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by GMATGuruNY » Tue May 26, 2015 11:45 am
prachi18oct wrote:Guidebook writer: I have visited hotelsthroughout the
country and have noticed that in those built before
1930the quality of the original carpentry work is
generally superior to that in hotels built afterward.
Clearly carpenters working on hotels before 1930
typically worked with more skill, care, and effort than
carpenters who have worked on hotels built
subsequently.
Which of the following, if true, most seriously weakens
the guidebook writer's argument?
(A) The quality of original carpentry in hotels is
generally far superior to the quality of original
carpentry in other structures, such as houses
and stores.
(B) Hotels built since 1930 can generally
accommodate more guests than those built
before 1930.
(C) The materials available to carpenters working
before 1930 were not significantly different in
quality from the materials available to
carpenters working after 1930.
(D) The better the quality oforiginal carpentry in a
building, the less likely that building is to fall into
disuse and be demolished.
(E) The average length of apprenticeship for
carpenters has declined significantly since 1930.

The premise is about a very limited SAMPLING: hotels that the guidebook writer has visited.
The conclusion is about the WHOLE: all hotels built before 1930.

The writer assumes that what is true for the SAMPLING is true for the WHOLE.
To weaken the conclusion, the correct answer choice will show that sampling ≠ whole.

Answer choice D: The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
Implication:
The country's poorly constructed hotels have probably been demolished.
Clearly, the guidebook writer could not have visited these hotels.
Thus, the sampling (the hotels that the writer has visited) ≠ the whole (all hotels built before 1930).

The correct answer is D.
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