BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Question I'm writing for interactive GMAT site--Magoosh

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 7
Joined: Tue Jun 16, 2009 10:20 am
Location: San Francisco

Question I'm writing for interactive GMAT site--Magoosh

by Clele75 » Wed Jun 17, 2009 9:14 am
Hi, beatthegmat community! I'm currently working on the verbal section for the interactive GMAT site, Magoosh, which will go live next month. I just wanted to get some feedback from the community in terms of how well the questions parallel those on the GMAT test as well as the level of difficulty of my question. Thanks!


The prevalence of a simian virus has been correlated with population density in gorillas. Recent anthropological fieldwork shows that gorillas living in the Plains of Morgania are nearly twice as likely to be infected than are gorillas living in the neighboring mountain range of Koluga. Nevertheless, the population density of Koluga gorillas is significantly greater than that of Morgania.

Which of the following could best account for the discrepancy noted above?

(A) During periods of little rainfall, Koluga gorillas often wander down into the plains in search of food.
(B) Dormant strains of the simian virus are often difficult to detect.
(C) Due to the Morgania gorilla’s natural habitat and its reclusive nature, researchers have tested a greater number of Koluga gorillas than Morgania gorillas.
(D) Infected Koluga gorillas behave very aggressively and are more difficult to subdue for testing.
(E) The Koluga and the Morgania both have similar markings on their backs but are classified as different subspecies.
The question provider
Top
Source: — Critical Reasoning |
Master | Next Rank: 500 Posts
Posts: 154
Joined: Thu Mar 19, 2009 12:55 pm
Thanked: 5 times
Followed by:1 members

by vinaynp » Wed Jun 17, 2009 9:52 am
IMO A)
Top
Junior | Next Rank: 30 Posts
Posts: 22
Joined: Tue May 19, 2009 8:01 pm
Thanked: 2 times
GMAT Score:740

by commit.gmat » Wed Jun 17, 2009 11:09 am
IMO B.

"B. Dormant strains of the simian virus are often difficult to detect."

It says that the virus is difficult to detect, thus questions the initial correlation that 'simian virus has been correlated with population density in gorillas'. Thus it says that, this high density is not the reason for the virus, thus strengthening the conclusion.
Top
Master | Next Rank: 500 Posts
Posts: 154
Joined: Thu Mar 19, 2009 12:55 pm
Thanked: 5 times
Followed by:1 members

by vinaynp » Wed Jun 17, 2009 11:53 am
commit.gmat wrote:IMO B.

"B. Dormant strains of the simian virus are often difficult to detect."

It says that the virus is difficult to detect, thus questions the initial correlation that 'simian virus has been correlated with population density in gorillas'. Thus it says that, this high density is not the reason for the virus, thus strengthening the conclusion.
Please read this:

https://en.wikipedia.org/wiki/Correlatio ... _causation
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 385
Joined: Sun May 24, 2009 3:55 pm
Thanked: 11 times
GMAT Score:740

by Domnu » Sat Jun 20, 2009 11:54 am
I believe that the question may be incorrect. There is no discrepancy from what has been written. To correct the question, instead of writing

"Nevertheless, the population density of Koluga gorillas is significantly greater than that of Morgania,"

we should have

Nevertheless, the population density of Morgania gorillas is significantly greater than that of Koluga.

In that case, the answer should be A.
Have you wondered how you could have found such a treasure? -T
Top
Legendary Member
Posts: 1169
Joined: Sun Jul 06, 2008 2:34 am
Thanked: 25 times
Followed by:1 members

by aj5105 » Sat Jun 20, 2009 8:44 pm
I too noticed the same.

Then the answer is (A).
Domnu wrote:I believe that the question may be incorrect. There is no discrepancy from what has been written. To correct the question, instead of writing

"Nevertheless, the population density of Koluga gorillas is significantly greater than that of Morgania,"

we should have

Nevertheless, the population density of Morgania gorillas is significantly greater than that of Koluga.

In that case, the answer should be A.
Top
Master | Next Rank: 500 Posts
Posts: 211
Joined: Thu Apr 09, 2009 12:17 pm
Thanked: 12 times
GMAT Score:680

by 4seasoncentre » Sat Jun 20, 2009 10:34 pm
No, I believe the original question was correct because it asks what might explain the 'discrepancy' between the theory and the findings.

Koluga --> More dense.
Koluga --> Less diseased.
but More Dense --> more diseased.
There is a discrepancy

IMO B.

A) If the Koluga go down to the plains, then they would be in a less dense area and the findings (that they are less likely to have the disease) is consistent with the theory, not a discrepancy.
B) The discrepancy is explained because many Koluga actually have the disease, but it is not showing up on the tests.
C) The size of the samples does not affect the proportion of infected gorillas.
D) Same as C.
E) It is unlikely that the scientists are misclassifying their results as a result of not being able to tell the gorillas apart.
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 385
Joined: Sun May 24, 2009 3:55 pm
Thanked: 11 times
GMAT Score:740

by Domnu » Sun Jun 21, 2009 8:55 am
4seasoncentre wrote:No, I believe the original question was correct because it asks what might explain the 'discrepancy' between the theory and the findings.

Koluga --> More dense.
Koluga --> Less diseased.
but More Dense --> more diseased.
There is a discrepancy

IMO B.

A) If the Koluga go down to the plains, then they would be in a less dense area and the findings (that they are less likely to have the disease) is consistent with the theory, not a discrepancy.
B) The discrepancy is explained because many Koluga actually have the disease, but it is not showing up on the tests.
C) The size of the samples does not affect the proportion of infected gorillas.
D) Same as C.
E) It is unlikely that the scientists are misclassifying their results as a result of not being able to tell the gorillas apart.
Ah, I see why the question could be correct then; the population itself may not be larger, but the density is twice. But I don't think E accounts for the discrepancy.
Have you wondered how you could have found such a treasure? -T
Top
Newbie | Next Rank: 10 Posts
Posts: 7
Joined: Tue Jun 16, 2009 10:20 am
Location: San Francisco

Answer and Explanations

by Clele75 » Mon Jun 22, 2009 8:23 am
I'm currently playing around with a few different approaches to how I will present the explanations on magoosh site. Let me know how these work for this question.



Discrepancy: M* gorillas are nearly twice as likely as K gorillas to have the virus even though K gorillas have twice the population density. We would expect K gorillas to be more likely to have the virus, not the other way around.

Attack: The passage above is based on the premise that the greater the population density the higher the likelihood a gorilla will be infected. The discrepancy in the two populations of M and K, respectively, shows us that some factor is skewing the findings of the fieldwork. Our answer must account for why the fieldwork has found that M gorillas have nearly twice the likelihood of the catching the virus, even though the population density of M is lower.

(A) Just because the K gorillas wander down into the plains during periods of little rainfall does not account for why their rate of infection is lower than that of the M gorilla. Furthermore, the argument never mentions rainfall.
(B) If dormant strains are difficult to detect then this should hold true for both M and K gorillas. Therefore, we still do not have an explanation for why the rates between the two are different.
(C) Though this answer choice cites a difference in the way fieldwork was conducted on the two groups of apes, the fact that more K gorillas were tested than M gorillas does not address the issue of percentage. That is, why, on average, are M gorillas more likely to have the virus and not the other way around as expected.
*(D) If those K gorillas who are infected are far more difficult to test, than the test results would be skewed so that most of the K gorillas tested would be non-infected gorillas. This would account for the discrepancy above.
(E) The fact that M and K gorillas have different markings does not address the discrepancy as to why M gorillas are more likely to be infected than K gorillas.

Answer (D)
The question provider
Top
Master | Next Rank: 500 Posts
Posts: 200
Joined: Sat Aug 22, 2015 10:27 am

by james33 » Sun May 15, 2016 7:55 pm
I would go with option B as the correct option
Top
Post new topic Post Reply
• Page 1 of 1