Guidebook writer: I have visited hotels throughout the country and hav

D it is

I may be wrong but This is what I think and I explain it with an example

Few years ago somebody ask me why do all the hollywood movies dubbed in hindi are good...
and I instinctively answered because only good movies are dubbed into hindi.

Similarly here, the reason why he found all the carpentry good in hotels before 1930, is because all the other hotels who had bad carpentry were either demolished or fallen down making the average of hotels made before 1930 with good carpentry the BEST

correct me if i'm Wrong.

Guidebook writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the 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?

Question type: Weaken the argument

Conclusion: Hotels built before 1930 have superior quality carpentry work carpenters working on hotels before 1930 typically worked with more skill, care, and effort.

Task at hand: Find an option that shows that hotels built before 1930 have superior quality carpentry work or that carpenters working on hotels before 1930 did not necessarily work with more skill, care, and effort.

(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. The argument is referring to the quality of the original carpentry in hotel. The original carpentry of houses and stores is not relevant.

(B) Hotels built since 1930 can generally accommodate more guests than those built before 1930. The argument is referring to the quality of the original carpentry in hotel. How many guests can be accommodated is not relevant.

(C) The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930. If the materials available to carpenters working before 1930 is almost the same as that used by carpenters after 1930 and the original carpentry work is still more superior, then this actually strengthening the fact that, in all probability, carpenters working on hotels before 1930 typically worked with more skill, care, and effort.

(D) The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished. This option tells us that, in general, buildings with poor quality original carpentry tend to fall into disuse and be demolished. This means that if some of the hotels that were built before 1930 had poor quality original carpentry, then it might have been demolished and that the only buildings now existing are the ones that had high quality original carpentry. In other words, one can’t necessarily say that hotels built before 1930 have superior quality carpentry work. The ones that may have had poor quality original carpentry may have been demolished already. This introduces a doubt and does not make the author conclusion seem as credible. In other words, the conclusion is weakened.

(E) The average length of apprenticeship for carpenters has declined significantly since 1930. The argument is referring to the quality of the original carpentry in hotel. The average length of apprenticeship is not relevant.

- Nitha

IMO D

It can be inferred from the statement that only the best of the best hotels built before 1930 are still around, the rest are demolished. Thus, the author did not get to see the full quality spectrum of hotels built before 1930.

Nasty one, I would go with D. My reasoning follows:



In this question, we have several possible answers that somewhat weaken the author's conclusion (B, D and E). But still we have to look for the one that weakens the most the conclusion and that provides evidence against it. That's why I chose D.

Really curious to see which one is the OA (and other gmatclubbers' answers as well).

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 of original 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.


My Explanation:
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A.) Nothing has been mentioned about houses and stores. It's just a distraction.

B.) This can either go against or in favour of the carpenters working post 1930. We can say that they might compromised on quality of work and instead focused on creating more space. On the other hand, we can also say that they were better skilled.
To conclude, we don’t have sufficient info to reach any concrete conclusion, so discard it.

C.) This can only strengthen the conclusion.

D.) If we go by method of elimination, we’ll be left with this option as the correct one. Moreover, on the basis of this option, we can say that the hotels built before 1930, which were examined by the writer are definitely of good quality. This means that hotels of inferior quality that were built before 1930 have not been taken into consideration for reaching the conclusion. This option, therefore, weakens the writer’s argument.

E.) What it can only do is strengthen the argument.
---------------

So, I will also go for option D.

Hope that helps.

Definitely D. The wording of the question is misleading, as many of them are. It is not true that one of the answers weakens the argument more than another or some others; one of the answers DOES weaken the argument, and the others DON'T.

The conclusion claims that the "skill, care and effort" of carpenters who worked on hotels before 1930 exceeded that of carpenters who worked on hotels after 1930. This is an extremely specific conclusion, and it does not have any of the more common loopholes -- such as comparing carpenters who worked on hotels before 1930 to ALL carpenters afterwards. The evidence is also quite specific: The author has seen that the "quality of the original carpentry work" (which clearly excludes materials, artistry of design, etc.) is generally better in hotels that were built before 1930 than in hotels that were built afterwards.

I for one was not able to see a missing assumption in this argument; it looks quite solid. But it is a Weaken question, and that means that there must BE a missing assumption. One of the answers must undermine or contradict that assumption, because that is how an argument is weakened on the GMAT. So let's look at the answer choices, and see which one points at the assumption that escaped our notice.

(A) Irrelevant. The evidence compares carpentry work in two groups of hotels, and the author reaches a conclusion about carpentry work in those two groups of hotels. How well the older carpenters did their work OUTSIDE of hotels does not matter.

(B) Irrelevant. This might be seen as a reason why carpenters after 1930 were less careful, but that does not affect the argument. The argument STARTS from the observation that the quality of the work in the newer hotels is not as good as in the older hotels, and then reaches a conclusion about the carpenters' behaviour. In order to weaken the argument, we need to show that OBSERVING lower quality does not necessarily mean that the carpenters WERE less careful. Why they may have been less careful does not affect the linkage between the observation and the behavioural conclusion.

(C) Strengthens the conclusion. It eliminates the possibility that the quality in the newer hotels is worse because the materials were actually so bad that even with the same level of care on the carpenter's part, the result looks bad. (Notice, however, that we have identified at least one assumption here. The argument assumes that the materials after 1930 were not so bad that they affect the visible quality of the work. Unfortunately, the answer choice supports the assumption rather than contradicting it.)

(D) This one says that a building with lower quality carpentry is more likely to be destroyed. Obviously, hotels built before 1930 have had more time to be destroyed than hotels built afterwards. THIS weakens the argument; it says that the guidebook writer is much less likely to SEE the hotels which were built with bad carpentry before 1930, because those are most likely to have disappeared. Consequently, the hotels STILL STANDING which were built before 1930 may not be a representative sample of all hotels which were built back then. Now we can see the assumption, which is that the hotels seen by the writer are representative of both the pre-1930 and the post-1930 time periods. (D) undermines that assumption, and weakens the argument.

(E) This is somewhat like (B). It could explain why later carpenters did not HAVE as much skill as earlier carpenters. It is irrelevant to the argument, however, which starts from observational evidence and concludes that they either did not have as much skill or did not use as much skill/care. To weaken the argument, we have to attack the linkage between the observations and the conclusion, and only (D) does that.

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.
- Irrelevant

B. Hotels built since 1930 can generally accommodate more guests than those built before 1930.
- Possible. Diffentiate between the 2 structures but no direct relationship with the caprpentary until we argue that carpentry was damanged by accomodatine more guests blah. Disregard

C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
- Doesnt weaken infact strengthen.
D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
-This gives us the idea that the old buildings have good carpentry since all other similarly aged buildings would have fall into misuse and demolished due to bad carpentry. Since the comparison is not fair in nature, it weakens the author's original argument.

E. The average length of apprenticeship for carpenters has declined significantly since 1930.
- Doesnt weaken infact strengthen.

The answer is 'D'.

"The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished."....It means that most hotels built before 1930 have been put into disuse or demolished...only a few remain with has been compared with modern hotels(which may or may not have better carpentry).

It is like comparing two scores say 3/3 with 8/10....clearly first ratio is greater,but success rate is more in second as first one ignores failed cases.

Option D does not impact the two groups of hotels in the same way: this preservational bias will be stronger the older the hotel. Shoddy buildings that are new are more likely to be standing than are those that are old, as the former will be demolished once they get older.

As for B, how does this difference influence the quality of the original carpentry work.

The lesson to be learned from this question: be wary of studies and surveys; ensure that the sample is representative of the population in question.

Imagine that there were a study of men grouped according to their ages, (A) over 90 , (B) close to 65, (C) close to 30. If it were found that, on average, the blood of the A men contained more a certain protein than did the blood of the B men, who in turn contained more of this protein than did the blood of the C men, would it be safe to conclude that the amount of this protein in a man's blood tends to increase as the man ages ?

Magoosh explanation

Guidebook writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the quality of the original carpentry work is generally superior to that in hotels build afterwards. [This is a factual observation.] Clearly carpenters working on hotels before 1930 typically worked with more skill, car, and effort than carpenters who have worked on hotels build subsequently. [This is a conclusion that would explain the factual observation.]

We are asked to weaken the argument. This means, we have to find another explanation for the factual observation (pre-1930 have good carpentry) that would support it even when the conclusion (pre-1930 carpenters were better than carpenters since) is false. In other words, even if pre-1930 carpenters are no better than later carpenters, why would the critic still observes much higher proportions of good carpentry in pre-1930 hotels?

Notice, some logical reflection has clarified our task for us, but there’s really no glaringly obvious alternate explanation for the higher proportions of good carpentry in pre-1930 hotels. We will have to look for relevant perspectives among the answer choices.

A. The quality of original carpentry in hotels is general far superior to the quality of carpentry in other structures, such as houses and stores.
True, but not helpful. Pre-1930 hotels had better carpentry than pre-1930 houses and stores. Post-1930 hotels have better carpentry than post-1930 houses and stores. This fact does not explain why any difference would not be apparent between pre-1930 hotels and post-1930 hotels.

B. Hotels build since 1930 can generally accommodate more guests than those built before 1930.
How many guests a hotel can accommodate has virtually no bearing on the quality of the carpentry. If the observations about differences in quality of carpentry were made from some kind of survey of hundreds of hotel guests, perhaps we could deduce that more had stayed in pre-1930 hotels simply because those hotels can accommodate more guests. But, the observation was in fact made by a single guidebook writer, a single person, who presumably stayed in a very large number of hotels. That persons conclusions presumably would have absolutely nothing to do with how many other people are staying in the hotel. This fact may well be true, but it’s irrelevant to this argument.

C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
Same materials in both time periods would not provide an alternative explanation for the difference in quality between pre-1930 and post-1930 hotels. In fact, arguably, this fact would strengthen the argument, not weaken it.

D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
This is fascinating. Old buildings with fine carpentry are more likely to be around still. Old buildings with mediocre carpentry are more likely to be no longer with us. Remember, the guidebook writer was implicitly speaking of proportions. The factual observation was, essentially: if we look at the proportion of pre-1930 hotel that have fine carpentry, and the proportion of post-1930 hotel that have fine carpentry, then the first proportion is greater than the second proportion. The guidebook writer argued that differences in the quality of the carpenters caused this difference in proportions.

This new fact provides an alternative explanation. Suppose carpenters now are just as good, just as skillful and careful, as carpenters from before 1930. For simplicity, suppose, on average, 3% of hotels built have fine carpentry, and the other 97% have mediocre/substandard carpentry, and assume that was just as true before 1930 as it is now. For hotels build before 1930, essentially all of those hotels with poor carpentry would have been knocked down, and the only ones still standing would be the 3% that had fine carpentry. Thus, when the guidebook writer goes to pre-1930 hotels still standing, still in service, the carpentry in almost all of them is of high quality. By contrast, hotels build in the past decade are all still standing, regardless of the quality of the carpentry. When the guidebook writer goes to these, only 3% have fine carpentry, and the rest do not. Thus, the guidebook writer could experience vast differences in the proportion of hotels with fine carpentry, and it would have nothing to do with the inherent quality of the respective carpenters. This is the correct answer.

E. The average length of apprenticeship for carpenters has declines significantly since 1930.
If anything, this would strengthen the argument. It would explain why pre-1930 carpenters would be more skillful. This does not weaken the argument.

Notice that we were asked to weaken the argument, and a couple of the answers did the opposite: provided information to strengthen the argument. That’s a typical GMAT CR pattern. Similarly, when you are asked to strengthen an argument, expect to see a couple answer choices that weaken the argument.

Notice, also, in all five answer choices, our reasoning was deeply bound to the context itself. We had to think through the details of the context to separate what was relevant from what was not relevant. That is quite different from the exercises of formal logic, which tends toward abstraction. GMAT CR logic is all about getting our hand dirty in the rough and tumble of real-world issues. That what the GMAT asks you to do because, once you’re a manager with your MBA and you’re out in the business world making decisions, that’s precisely what you are going to be doing all day every day in your job.

Guidebook writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the 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.out of scope

(B) Hotels built since 1930 can generally accommodate more guests than those built before 1930.out of scope

(C) The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930. out of scope, since the argument addresses the skill of the carpenter and not the materials used

(D) The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.There could have been many less skilled carpenters who made buildings that were so poorly made that they fell into disuse and were demolished.

(E) The average length of apprenticeship for carpenters has declined significantly since 1930. could strengthen the argument

Guidebook Writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the 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?

So, Quality of furniture in hotels built before 1930 > Quality of furniture in hotels built after1930
Hence -> Quality of skill, care and effort is better for carpenters before 1930 > Quality of skill, care and effort is better for carpenters after1930

We need to weaken it. If we see it is A -> B -> so this is an causal argument
Some of the strategies we can use:
1) The data is biased.
2) B -> A
3) There is some other reason C, such that C -> B and A is just present there.

Lets check the options now:


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.
As soon as you see "Other", most probably, it is out of scope as we are comparing furniture in hotel built before 1930 and furniture in hotel built after 1930 -> hence Wrong

B. Hotels built since 1930 can generally accommodate more guests than those built before 1930.
Guests don't have an impact on the furniture. Out of scope.

C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
So, the materials are of equal quality, so this option should support the conclusion instead of weaken the argument -> Hence wrong

D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
Now, this option talks that data provided is distorted.

For example: lets say out of 100 hotel built before 1930, 10% of the hotel have good furniture
so 10 hotels with a good quality.
Now, out of 100, 50 hotels are demolished, so if we observe the quality now, we can see 10/50 = 20% so we have a false impression that we have there are more hotels with good furniture.

lets hotel built after 1930, 15% of the hotels have good furniture. Even though 15% > 10% but as hotels were demolished, we have a wrong set to compare.
Hence the data provided is wrong or biased -> Hence the option weakens the argument.

E. The average length of apprenticeship for carpenters has declined significantly since 1930.
Average length of apprenticeship doesn't indicate the quality of furniture produced is low as we need to make another assumption that length of apprenticeship is directly proportional to quality of furniture manufactured -> Can be next best answer. -> but we have D) better answer

Let us know if you have any other queries.

to negate, we must prove that the skills of the carpenters did not get worse, or that the hotels which the writer visited were among the few of the ones built before 1930, which were built with high quality carpentry so that to last for a long time. it might be the case that carpets of some hotels from 1930 were not good, and thus, such hotels just simply did not last to live the writer's time...

A - other structures - irrelevant.
B - this might give alternative reason why the conditions of the carpets in hotels built after 1930 are worse. yet, it does not provide evidence that the quality is the same.
C - this actually strengthens the argument. same materials - but quality different. nowadays carpenters - bad.
D - ok, so the hotels built before 1930 are standing still, because they had better quality of carpentry. this means that there were hotels with lower quality, but which did not get to the writer's time... looks good. Now, the writer compares the hotels built before 1930, with exceptionally high quality, with hotels built after 1930, with "standard" quality. we can see that the comparison is not accurate.
E - this one strengthens the argument.

The guidebook writer states that carpentry work was superior in the old hotels than in the new ones. If the carpentry work was really superior it is implied that all those hotels should have endured the test of time. "D" implies that some of the buildings have already fallen into disuse and have been demolished which suggests that the carpentry work wasn't that superior.

This question could be categorized as a weaken the argument question or as a flawed argument question.

The Guidebook writer is trying to present a statistical argument, but fails to recognize that the SAMPLE is not representative of the ENTIRE POPULATION.

The SAMPLE consists of pre-1930's hotels that are still standing
The writer uses this sample to make a conclusion about ALL hotels built before 1930 (hotels that are still standing and those that are no longer standing)
So, there's already a problem with the argument, since it's quite possible that the carpentry in many pre-1930 hotels was so awful that those hotels fell apart very quickly.
So, just because the pre-1930's hotels that are still standing have great carpentry, we can't then make sweeping conclusions about the carpentry in ALL pre-1930's hotels

Answer choice D essentially says "the better the carpentry, the greater the chances of a hotel's survival"
It points out the possibility that many pre-1930's hotels could have had bad carpentry and, thus, had to be demolished.

Cheers,
Brent

Guidebook writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the 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. -We are comparing the hotels with hotels in the passage.

(B) Hotels built since 1930 can generally accommodate more guests than those built before 1930. -More guests? Out of scope

(C) The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930. -This strengthens the argument because if the materials available to the carpenters of both the eras are same then the authors conclusion is correct.

(D) The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished. -Correct. Good quality things stay stable for longer time. Thus, the author visited only good quality hotels. Hence we can't conclude that "all" previous era carpenters are better.

(E) The average length of apprenticeship for carpenters has declined significantly since 1930. -Out of scope

I stuck in this question between B and D and I don't understand why D is better. In D we also need to "dream up" something, which is not in the passage itself, namely we need to assume the year at which Guidebook writer made his visits. Answer D is correct if visits are made nowadays, but what about if the visites made in 1940? Then D logic flaws, because not too many hotels built before 30es had been demolished at that time, while greater accomodation in choice B could mean greater expluatation rate which impact the quality of carpentry. Passage doesn't tell us the time when guidebok writer made his conslusions and visits, so for me B looks stronger as the higher expluatation rate would cause damage to carpentry quickly, therefore argument in B can be applied in most of the cases disregarding time when visits were made.