Guidebook writer

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Guidebook writer

by geet » Mon Jul 13, 2009 6:35 am
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.
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.

OA l8r...do explain your logic!!!

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by cameronwu » Mon Jul 13, 2009 6:54 am
By process of elimination, I pick B.

A - This doesn't weaken the question. There is no need for a comparison to other structures because the stimulus only makes a claim about carpentry in hotels, and not carpentry overall.

C - This actually strengthens the argument instead of weakening it. When working with nearly identical materials, the pre-1930s exhibited superior quality, which is the conclusion.

D - This doesn't support any argument. It's stating the obvious.

E - This also strengthens the argument instead of weakening it. If apprenticeship length has declined, then you might be able to assume that the quality in carpenters working on hotels (assuming that hotel carpenters go through apprenticeships) would have a positive correlation with the decline in the length of their apprenticeships.

Now, I select B because all the others don't work, but I would be hesitant about positively identifying B based on its logic. So it says that hotels built after 1930 are built to accomodate more guests. You have to make a big assumption here to get to the weakening aspect of it. So since they accomodate more guests, you have to assume it's bigger and more complex, and thus the quality of carpentry might be lower because of the structural difficulty in building it, as opposed to a smaller building that probably didn't require a feat of mega-engineering. So I'm not completely guns-a-blazing for picking B because it's not really that great of an answer. However, out of the 5, it does most seriously weaken the argument.

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by dendude » Mon Jul 13, 2009 8:02 am
I arrive at D after using POE.

Its possible that the only remaining buildings from pre-1930s are the buildings that were continued to be used and not demolished.
In other words, there could have been many more other buildings, built before 1930s, that had shoddy carpentry work and were hence demolished.
So by just comparing the surviving pre-1930s buildings to the post-1930s buildings (probably of which none were disused or demolished) the argument fails.

I thought B was OOS.

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by cameronwu » Mon Jul 13, 2009 8:12 am
dendude wrote:I arrive at D after using POE.

Its possible that the only remaining buildings from pre-1930s are the buildings that were continued to be used and not demolished.
In other words, there could have been many more other buildings, built before 1930s, that had shoddy carpentry work and were hence demolished.
So by just comparing the surviving pre-1930s buildings to the post-1930s buildings (probably of which none were disused or demolished) the argument fails.

I thought B was OOS.
^^ Better logic. Conceded! I change my answer to D too.

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by turbo jet » Mon Jul 13, 2009 8:22 am
IMO: C

Author says that quality of carpenters is responsible for quality of woodwork.

I chose C bec it gives me a hint that there is an alternate cause for difference in quality of structures. (quality of material)

OA please.

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by geet » Mon Jul 13, 2009 8:51 am
Gud .......OA is D

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by turbo jet » Tue Jul 14, 2009 2:11 am
Good qs geet and great explanation dendude!!!
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by mmslf75 » Sun Jan 10, 2010 1:26 am
This is from OG 12,

cant understand what's happening IMO C

As we shift the logic of argument from CARPENTERS to MATERIAL QUALITY that weakens

What I miss ?

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by Testluv » Sun Jan 10, 2010 3:12 pm
mmslf75 wrote:This is from OG 12,

cant understand what's happening IMO C

As we shift the logic of argument from CARPENTERS to MATERIAL QUALITY that weakens

What I miss ?
Choice C reads:
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 actually strengthens the argument. We can use the Kaplan denial test to see this: if the materials WERE significantly different, then it would open up the possibility that the reason the old buildings are better is because of better quality, and so would weaken the argument. Because the denial of choice C weakens, choice C itself must be a strengthener.

dendude's explanation for why choice D is correct is spot-on. If choice D is true, then it suggests that all the crappy old buildings aren't around any more-->this weakens the argument that the old carpenters were better (it's not that they're better, instead it's that the crappy old buildings just aren't around any more).
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by NZOMNIAC » Mon May 31, 2010 3:39 pm
i somehow think D strengthens the argument

If D were true , then is means crappy buildings are less likely to exist. which means crappy buildings before 1930 as well after 1930 are less likely to exist...

so in no way does it impact the argument

for e.g lets say total 100 hotels were built before 1930 and lets say 100 were built after 1930
lets say 70 were good quality and 30 were crappy
let say 60 were good quality and 40 were crappy

so now the guidebook writer is comparing 70 before 1930 with 60 after 1930 and correctly concludes higher quality before 1930


I understand that i have used numbers in my favour above, but the point is the option D impacts hotels before and after 1930 in same way so there is no difference


I think correct ans is B
becuase its shows how the hotels before 1930 and after 1930 are differennt, potentially causing the diff in quality

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by kevincanspain » Mon May 31, 2010 3:47 pm
NZOMNIAC wrote:i somehow think D strengthens the argument

If D were true , then is means crappy buildings are less likely to exist. which means crappy buildings before 1930 as well after 1930 are less likely to exist...

so in no way does it impact the argument

for e.g lets say total 100 hotels were built before 1930 and lets say 100 were built after 1930
lets say 70 were good quality and 30 were crappy
let say 60 were good quality and 40 were crappy

so now the guidebook writer is comparing 70 before 1930 with 60 after 1930 and correctly concludes higher quality before 1930


I understand that i have used numbers in my favour above, but the point is the option D impacts hotels before and after 1930 in same way so there is no difference


I think correct ans is B
becuase its shows how the hotels before 1930 and after 1930 are differennt, potentially causing the diff in quality
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 ?
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by NZOMNIAC » Mon May 31, 2010 3:58 pm
option D does not say older the hotel the more likely it will get demolished. Its an assumption that you are making. Which maybe fair

But I think B is correct because firstly it compares across the two time periods ; before 1930 and after 1930

If i can make an assumption that if we have more guests per hotel after 1930 , then there are fewer hotels after 1930

and so B weakens the argument and shows that we are not comparing apples to apples [/quote]

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by Testluv » Mon May 31, 2010 4:13 pm
Choice D tells us the lower the quality of the building, the less likely it is that it is still around. So, the only surviving hotels from the 1930s are those that were very well constructed.

Thus, as Kevin points out, the 1930s hotels currently standing are misrepresentative of all 1930s hotels.

Thus, Choice D weakens the argument.

The number of guests that the hotels accommodate is far outside the scope of this argument, and choice B is definitely wrong.
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by NZOMNIAC » Mon May 31, 2010 4:28 pm
if hotels before 1930 are misrepresentative of hotels before 1930s
then hotels after 1930 are also misrepresentative of hotels after 1930s


i think it boils down to assumption made to justify is each option correct

If B has to be correct , then I can assume that if total number of guests is constant then as number of guest per hotel increases then total number of hotels will reduce

If D has to be correct, then we need assumption that older building is likely to be demolished/fall into disuse

It may appear that I am trying to justify answer B, but I don't get the sample argument since it effects both samples in the same way unless we assume that "that older building is more likely to be demolished/fall into disuse"

I think on the exam I will choose D since OA is D, but I would really want to know the real reason y D is the OA

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by Testluv » Mon May 31, 2010 5:52 pm
Here's a rule you can use throughout the GMAT: never make your own assumptions. That is, the correct answer will NEVER be contingent on any assumptions you have to make.

The longer the building is around the more likely it will fall into disuse. This is not an assumption--it is a deduction--something that must be true. This must be true because the converse--that a building one day old is just as likely to fall into disrepair as buildings decades' old--is absurd.

And this:
if hotels before 1930 are misrepresentative of hotels before 1930s
is not quite what either of Kevin or I was saying. Instead, the surviving buildings from the 1930s do not genuinely represent all buildings from the 1930s. We can't take the quality of surviving 1930s building as a representation of the quality of all 1930s building because the quality of surviving 1930s buildings will be very good--since all the crappy ones would have fallen to the wayside.

...that is the "real" reason that choice D is correct. :)
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