In tests for Feline Leukemia Virus (FeLV), a serious disease of domest

Question

In tests for Feline Leukemia Virus (FeLV), a serious disease of domestic cats, a false positive result indicates that a cat has FeLV, when in fact, it does not; a false negative result indicates that a cat does not have FeLV when, in fact, it does. To detect FeLV most accurately, veterinarians should use the laboratory test that has the lowest proportion of false negative results.

Which of the following, if true, gives the most support to the recommendation above?

A. A certain proportion of results are inconclusive no matter which laboratory test is used.

B. There is no known cure for FeLV, although some chemotherapeutic agents may produce a temporary remission and some antiviral agents may reduce the amount of virus present in infected cats.

C. Cats do not readily submit to having their blood drawn for a test.

D. Upon receiving a positive test result, veterinarians often submit a second sample to be retested for confirmation.

E. All laboratory tests to detect FeLV have the same rate of false positive results.

Suruchim12 · Answer

Can someone pls explain why E and not D is the right answer?

If every +ve test means retesting, will that not help in better accuracy of Felv detection? So even if theres a false +ve result upon retesting - there are more chances of the true results coming out right? So lab tests with more fake +ve results (or in other words lab tests with less fake - ve results) should be chosen -  hence strengthens the argument

Unless we assume that the retesting will just go into a loop of fake +ve results!

As for E - just because all lab tests have the same rate of false positive result - doesn't mean the accuracy of Felv testing will increase so deosnt it weaken the argument?

Ashutoshranjan881 · Answer

I can give a try. We can easily eliminate A B and C the main confusion is between D and E. Between D and E the later support the conclusion more directly if E is not correct then D become irrelevant if option E were not correct which means laboratory test will have more false positives then option d which is taking a second test will have no benefit

Sam1993 · Answer

option E strengthens the most because accuracy of any test depend on number of false positi es and false negatives. if all tests have equal proportion of false positives , then the test with lowest proportion of false negatives is the most accurate.

reed990 · Answer

I understand the conclusion "Most accurate" makes "E" make sense, since same false negative + low false negative = better accuracy. However, D still looks better to me: after ruling out false negative, positive = real positive + false positive, 2nd test makes the case positive even less, which leads to the best accuracy.

SirSanguine · Answer

Suruchim12 
Both D and E strengthens the argument (supports the decission). 
But think about it like this if you have two criteria to evaluate for choosing and one critera is same for all , now all what you need to do is to compare the second critera..which is exactly what the conclusion in question says..that decide based on only one critera and whats a better reason to rely totally on one critera than having the first critera common?

flyhigh99 · Answer

why is it not A? Can a proper explanation please be posted?

Sahith_Manikanta · Answer

KarishmaB   GMATNinja   Bunuel   MartyMurray , can you please explain solution to this question? I've selected Option D as it is the only option which seemed relevant to me. I had to consider no retesting is done for negative result as it is not mentioned anywhere, and since negative results are not rechecked, it is having higher inaccuracy.

I don't understand how E is the right answer. Please help.

Dhruvek · Answer

Conclusion of Argument :To detect FeLV most accurately, veterinarians should use the laboratory test that has the lowest proportion of false negative results.

Before explaining the Option E , You should be clear with the following:

If X caused Y then the following Statement can be strengthened in following ways: 
 
 Eliminating reverse causality – Y didn’t cause X 
 Eliminating third factor – There’s no Z that caused both X and Y 
 Eliminating pure co-incidence – The correlation between X and Y is not a result of pure co-incidence 
 Eliminating an alternate cause – There is no other cause of Y.

In this Argument , Option E says All laboratory tests to detect FeLV have the same rate of false positive results. Lets Say if False positive rate was more , then inaccuracy would also be more but now since option mention the false positive rate is same , therefore we are eliminating the factor that can result in more inaccuracy. That is why option e is   strengthening   .

In tests for Feline Leukemia Virus (FeLV), a serious disease of domest

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

In tests for Feline Leukemia Virus (FeLV), a serious disease of domest

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards