IMO A)

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.

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

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.

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.

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.

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.

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)

I would go with option B as the correct option