Challenging CR

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Challenging CR

by chaitanya.mehrotra » Sun Jun 26, 2011 1:22 pm
A physically active lifestyle has been shown to help increase longevity. In the Wistar region of Bellaria, the average age at death is considerably higher than in any other part of the country. Wistar is the only mountainous part of Bellaria. A mountainous terrain makes even such basic activities as walking relatively strenuous; it essentially imposes a physically active lifestyle on people. Clearly, this circumstance explains the long lives of people in Wistar.

Which of the following, if true, most seriously weakens the argument?
(A) In Bellaria all medical expenses are paid by the government, so that personal income does not affect the quality of
health care a person receives.
(B) The Wistar region is one of Bellaria's least populated regions.
(C) Many people who live in the Wistar region have moved there in middle age or upon retirement.
(D) The many opportunities for hiking, skiing, and other outdoor activities that Wistar's mountains offer make it a favorite
destination for vacationing Bellarians.
(E) Per capita spending on recreational activities is no higher in Wistar than it is in other regions of Bellaria.

Doubt: Option C can be argued against saying that the people after moving to Wistar were exposed to the rigorous lifestyle thus had a high average life .
Option A on the other hand can be said to be weakening the argument in the sense here that since govt was providing healthcare thus people had access to better health care facility which contributed in their long life.Thus this provided another reason for the long average life of the people.


OA C[/b]

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by David@VeritasPrep » Sun Jun 26, 2011 4:51 pm
Thank you for posting this question!!!

I have been waiting for a while to utter one of my favorite phrases. And here is the question to do it!

Are you ready, here it comes...

"A difference requires a distinction" (in order to explain that difference).

For example if I were to try to explain why some people score higher on the GMAT than others, I could not do this by saying "everybody gets the same type of marker and notepad" or "almost everyone gets 75 minutes for each section."

Do you see the problem?? I cannot explain why some people do better than others on the exam by pointing out the things that they have in common. I would need to focus on a difference "Some people study more effectively than others" would be a better explanation for the difference in scores.

Now on this problem at hand we are trying to offer an alternative explain a difference "In the Wistar region of Bellaria, the average age at death is considerably higher than in any other part of the country." We do not want the cause of the difference to be the physical lifestyle in Wisteria so we will try to find another cause to weaken this.

So you see we need something that is true of Wistar but not true of Bellaria in general.

If I were to say, "the diet of Wistar is identical to that of the rest of Bellaria" I would not be able to explain the difference of people dying at a later age in Wistar.

Answer Choice A is this type of answer. It does not point out a difference, but rather points out something in common to all of Bellaria! It says, "(A) In Bellaria all medical expenses are paid by the government, so that personal income does not affect the quality of health care a person receives." This applies to all of Bellaria and so would not explain why Wistar would be different in any respect.

Choice E would also suffer from this and be eliminated immediately. The other choices, B,C, and D point to differences, but only choice C points to a difference that could logical explain the older age of death in Wistar.
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by chaitanya.mehrotra » Sun Jun 26, 2011 9:35 pm
Thanks David its clear now

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by GMATMadeEasy » Mon Jun 27, 2011 6:22 am
@David: Thanks for this fantastic explanation. I had noted this fallacy in many questions where GMAC plays a trick by removing an alternate possibility -- by falsely showing that there is no difference in both the cases compared hence, it uses the same to strengthen.

GMAT Examples you have given are to the point but I wonder there are situations in which providing the information might help to evaluate the argument such as whether scoring algorithm used for both the students is same.This ,based on type of question, can strengthen or weaken.How to relate this case with difference and distinction ? The objective of the question is to distinguish a different situation (relevant to the question as in example above) from the situation you have given.

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by GMATMadeEasy » Thu Jun 30, 2011 7:40 am
GMAtpep Question:

In parts of South America, vitamin-A deficiency is a serious health problem, especially among children. In one region, agriculturists hope to improve nutrition by encouraging farmers to plant a new variety of sweet potato called SPK004 that is rich in betacarotene, which the body converts into vitamin A. The plan has good chances of success, since sweet potato is a staple of the region's diet and agriculture, and the varieties currently grown contain little beta-carotene. Which of the following, if true, most strongly supports the prediction that the plan will succeed?
A. There are other vegetables currently grown in the region that contain more beta-carotene than the currently cultivated varieties of sweet potato do.
B. The flesh of SPK004 differs from that of the currently cultivated sweet potatoes in colors and textures, so traditional foods would look somewhat different when prepared from SPK004.
C. For successful cultivation of SPK004, a soil significantly richer in nitrogen is needed than is needed for the varieties of sweet potato currently cultivated in the region.
D. There are no other varieties of sweet potato that are significantly richer in beta-carotene than SPK004 is.
E. The currently cultivated varieties of sweet potato contain no important nutrients that SPK004 lacks.

Oa is E; i am sure D is discussed by many people in past.

@David: Could you help to use you above approach or a robeust way when we should be deviated by analogy and we should not such as in option D above? First reactoin from brain aftee seeing D is Nirvana :). I am trying to devise a fool-proof stategy , a way ,may be in abstact words, that tell me when comparison works.

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by David@VeritasPrep » Thu Jun 30, 2011 1:32 pm
Easy -

This is a plan question. So if you take my advice you will use the "automatic conclusion." What is the automatic conclusion? It is the conclusion that you supply because on a plan question there really is no conclusion. The automatic conclusion is "The PLAN will achieve the GOAL." So it is up to you to figure out what the plan is and the goal is.

In this case the goal is to "improve nutrition." The plan is to encourage the farmers in South America to grow the new sweet potato. So we want to say that encouraging the farmers to grow this sweet potato will improve nutrition in the diet in South America.

Now, you mention choice D. This is a choice that I always warn my students against. We are talking about this plan - this sweet potato. The conclusion is not that this is the best sweet potato ever - or that it has the most nutrition ever. The conclusion is only that this encouragement will result in better nutrition. So as long as this is true it NEVER will matter if another plan is better. I would eliminate choice D in 1 second. It is talking about another plan, not this one.

So if we are going to improve nutrition then this sweet potato needs to not reduce other important vitamins. So E is the choice. The key is that this is talking about the current sweet potato. Those are the only ones that matter the current and SPK004.

Here is the fool-proof strategy, for a plan question, an answer choice that discusses another plan (or sweet potato) is never the correct answer.
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by GMATMadeEasy » Thu Jun 30, 2011 2:08 pm
Thanks David. Yes that is how I do plan question and revise my CR notes everyday I take shower.

I am solving GMATPrep question CR set, will share if anything new encountered.

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by Sanjay2706 » Thu Jun 30, 2011 8:09 pm
As usual great explanation from David.
Yes IMO C is the right answer.

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by amit2k9 » Fri Jul 01, 2011 12:11 am
well the only hitch in the argument is the average age at death is more than any other part in the country. This has to be attacked as it is the basis of the argument.

C does exactly the same.The people have moved from other parts.
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by winniethepooh » Mon Mar 05, 2012 1:44 pm
Awesome explanations by David!

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by tanviet » Fri Apr 06, 2012 5:18 am
David@VeritasPrep wrote:Easy -

This is a plan question. So if you take my advice you will use the "automatic conclusion." What is the automatic conclusion? It is the conclusion that you supply because on a plan question there really is no conclusion. The automatic conclusion is "The PLAN will achieve the GOAL." So it is up to you to figure out what the plan is and the goal is.

In this case the goal is to "improve nutrition." The plan is to encourage the farmers in South America to grow the new sweet potato. So we want to say that encouraging the farmers to grow this sweet potato will improve nutrition in the diet in South America.

Now, you mention choice D. This is a choice that I always warn my students against. We are talking about this plan - this sweet potato. The conclusion is not that this is the best sweet potato ever - or that it has the most nutrition ever. The conclusion is only that this encouragement will result in better nutrition. So as long as this is true it NEVER will matter if another plan is better. I would eliminate choice D in 1 second. It is talking about another plan, not this one.

So if we are going to improve nutrition then this sweet potato needs to not reduce other important vitamins. So E is the choice. The key is that this is talking about the current sweet potato. Those are the only ones that matter the current and SPK004.

Here is the fool-proof strategy, for a plan question, an answer choice that discusses another plan (or sweet potato) is never the correct answer.
Thank you David.


For plan question we find new information which directly support/weaken the plan.

but for strengthening/weakening quesions, we phrephrase an assumption and possible strengthener/weakener before going to reading answer choices.

Is my thinking correct? , pls, comment expert, members.

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by tanviet » Fri Apr 06, 2012 5:23 am
David@VeritasPrep wrote:Easy -

This is a plan question. So if you take my advice you will use the "automatic conclusion." What is the automatic conclusion? It is the conclusion that you supply because on a plan question there really is no conclusion. The automatic conclusion is "The PLAN will achieve the GOAL." So it is up to you to figure out what the plan is and the goal is.

In this case the goal is to "improve nutrition." The plan is to encourage the farmers in South America to grow the new sweet potato. So we want to say that encouraging the farmers to grow this sweet potato will improve nutrition in the diet in South America.

Now, you mention choice D. This is a choice that I always warn my students against. We are talking about this plan - this sweet potato. The conclusion is not that this is the best sweet potato ever - or that it has the most nutrition ever. The conclusion is only that this encouragement will result in better nutrition. So as long as this is true it NEVER will matter if another plan is better. I would eliminate choice D in 1 second. It is talking about another plan, not this one.

So if we are going to improve nutrition then this sweet potato needs to not reduce other important vitamins. So E is the choice. The key is that this is talking about the current sweet potato. Those are the only ones that matter the current and SPK004.

Here is the fool-proof strategy, for a plan question, an answer choice that discusses another plan (or sweet potato) is never the correct answer.
Thank you David.


For plan question we find new information which directly support/weaken the plan.

but for strengthening/weakening quesions, we phrephrase an assumption and possible strengthener/weakener before going to reading answer choices.

Is my thinking correct? , pls, comment expert, members.

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by [email protected] » Wed Apr 11, 2012 4:13 am
This is a very good question....

All I would say in this aspect is that the option D says that 'There are no other varieties of sweet potato that are significantly richer in beta-carotene than SPK004 is.'

Option D serves as the Defender assumption for this stimulus. Had the question asked, what is the basic assumption of this question, then the answer choice D would be most appropriate answer choice among the options given.

Always remember that in plan questions when it comes to a specific plan, it is always assumed that a plan is chosen because it is already evaluated and thats why chosen. So the basic assumption is that This particular plan is chosen after evaluating all the other plans and hence no other plans were as good as this plan.

But this is a strengthen question and now we are only concerned with reaching our goal as the plan is already selected. So which are the parameters based on which we will reach our goal continuing on the same plan.

So lets consider option E now,

The currently cultivated varieties of sweet potato contain no important nutrients that SPK004 lacks.

If this thing does not happen and say that the current sweet potato contains Vitamin E in greater quantities and the new sweet potato contains no vitamin E and may lead to some other deficiency, then the villagers are basically facing some deficiency or the other...

So how can the current plan give solution to the problem. Hence it is a strength part of the argument.
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by [email protected] » Wed Apr 11, 2012 4:22 am
One more thing I forgot to say and in order for everybody to understand this question more easily is that,

Lets say you are a manager of the villager or for that particular project, and between the two plans A and B,

Lets say you chose plan A and so the manager's boss and other people in the team assume that the plan A is definately better than plan B. Therefore the manager has evaluated both the plans properly.

Now after choosing plan A the manager has certain parameters through which he and his team will reach the goal faster. Now in those parameters, the parameters which will help to reach the goal will be the strengths of the plan and the parameters that will not help the plan to meet its goal will be the plan's weakness.

I hope all of you understood this...

A bit confusing but very interesting indeed to understand as all of us will be tomorrow's managers...

Thank You...
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by ronnie1985 » Wed Apr 11, 2012 9:33 am
Thank you experts...
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