Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 22 May 2013, 23:13

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

 Question banks Downloads My Bookmarks Reviews
Author Message
TAGS:
Intern
Joined: 29 Jun 2011
Posts: 38
Location: Yugoslavia
Concentration: International Business, Entrepreneurship
GMAT 1: 700 Q48 V38
GPA: 3.72
Followers: 0

Kudos [?]: 2 [0], given: 3

In tests for Feline Leukemia Virus (FeLV), a serious disease [#permalink]  10 Aug 2011, 02:39
00:00

Question Stats:

74% (02:06) correct 25% (01:13) wrong based on 0 sessions
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.

OA is
[Reveal] Spoiler:
E

My question is this.....kaplan explains that D is irrelevant and costly. However, if the the Veteranarians agree to only using tests with the least false negatives , then the proportion of false positives will increase correct? Either way there will be inaccurate test results, its just a matter of whether they are more dangerous (false negative) or less dangerous (false positive). So wouldnt it be better to have false positives and then re take the test?
[Reveal] Spoiler: OA
 Kaplan GMAT Prep Discount Codes Knewton GMAT Discount Codes Veritas Prep GMAT Discount Codes
Manager
Status: Writing my first GMAT on MArch 28/2012
Joined: 13 Sep 2010
Posts: 124
Location: Canada
Concentration: Finance, International Business
Schools: Schulich, Rotman '15
GMAT Date: 03-28-2012
GPA: 2.8
WE: Corporate Finance (Other)
Followers: 1

Kudos [?]: 22 [0], given: 9

Re: Cat False Positive [#permalink]  10 Aug 2011, 04:22
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?

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

This one is simply a matter of there being 2 tests. Event Neg and Event Pos. So in the case of E is is saying that NO MATTER WHAT all laboratory tests to detect FeLV will have the same rate of false positive. Which means that you're going to want to pick the lab test that has the lowest proportion of negative results and therefore it supports the theory. so E is the correct answer.

To make it easier to understand, you obviously want the least number of errors so lets take 5 random tests:
-------------Pos Errors----Neg Errors-------Total Errors
Lab test 1-------3-------------2----------------5
Lab test 2-------3-------------3----------------6
Lab test 3-------3-------------4----------------7
Lab test 4-------3-------------1----------------4
Lab test 5-------3-------------2----------------5

Therefore it doesnt matter what the proportion of Pos errors is, the total number of errors goes down. And for the record with False Pos it tells them that they have FeLV when they don't so they would have to take the test again to confirm because it would be costly for treatment just as they would take the False Neg again to make sure the cat is ok. Either way they would take the test to confirm a second time there is no difference between two false.
_________________

“Focus on the journey, not the destination. Joy is found not in finishing an activity but in doing it.” - Greg Anderson

Follow my Journey at: nphelan-s-road-to-117533.html

Kudos? Don't mind if I do!

Manager
Joined: 27 Apr 2008
Posts: 192
Followers: 1

Kudos [?]: 22 [0], given: 1

Re: Cat False Positive [#permalink]  10 Aug 2011, 06:28
nphelan wrote:
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?

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

This one is simply a matter of there being 2 tests. Event Neg and Event Pos. So in the case of E is is saying that NO MATTER WHAT all laboratory tests to detect FeLV will have the same rate of false positive. Which means that you're going to want to pick the lab test that has the lowest proportion of negative results and therefore it supports the theory. so E is the correct answer.

To make it easier to understand, you obviously want the least number of errors so lets take 5 random tests:
-------------Pos Errors----Neg Errors-------Total Errors
Lab test 1-------3-------------2----------------5
Lab test 2-------3-------------3----------------6
Lab test 3-------3-------------4----------------7
Lab test 4-------3-------------1----------------4
Lab test 5-------3-------------2----------------5

Therefore it doesnt matter what the proportion of Pos errors is, the total number of errors goes down. And for the record with False Pos it tells them that they have FeLV when they don't so they would have to take the test again to confirm because it would be costly for treatment just as they would take the False Neg again to make sure the cat is ok. Either way they would take the test to confirm a second time there is no difference between two false.

I narrowed my choices down to D and E but picked D....thanks for the great explanation.
Manager
Joined: 24 Nov 2010
Posts: 216
Location: United States (CA)
Concentration: Technology, Entrepreneurship
Schools: Ross '15, Duke '15
Followers: 2

Kudos [?]: 28 [0], given: 7

Re: Cat False Positive [#permalink]  10 Aug 2011, 06:46
+1 for E
Manager
Joined: 27 Apr 2008
Posts: 192
Followers: 1

Kudos [?]: 22 [0], given: 1

Re: Cat False Positive [#permalink]  10 Aug 2011, 10:19
Intern
Joined: 29 Jun 2011
Posts: 38
Location: Yugoslavia
Concentration: International Business, Entrepreneurship
GMAT 1: 700 Q48 V38
GPA: 3.72
Followers: 0

Kudos [?]: 2 [0], given: 3

Re: Cat False Positive [#permalink]  10 Aug 2011, 12:00
Good explanations i kudos but im on a mobile phone

Posted from my mobile device
Senior Manager
Joined: 25 Nov 2011
Posts: 261
Location: India
Concentration: Technology, General Management
GPA: 3.95
WE: Information Technology (Computer Software)
Followers: 3

Kudos [?]: 20 [0], given: 20

Re: In tests for Feline Leukemia Virus (FeLV), a serious disease [#permalink]  26 Feb 2012, 06:51
There are 2 ways a report of a lab can be questioned:
based on its false -ve rate & fase +ve rate.

If all labs give same result for +ve rate, obviously we need to depend on false -ve rate. Hence E is correct.

As per D - no matter what the first report says, doctors are going to submit for second test for confirmation. What if the second result contradicts with the first one? There is no answer for this question and hence D is not correct.
_________________

-------------------------
-Aravind Chembeti

Verbal GMAT Forum Moderator
Status: Flying over the cloud!
Joined: 17 Aug 2011
Posts: 787
Location: Viet Nam
Concentration: International Business, Finance
GPA: 3.07
Followers: 18

Kudos [?]: 80 [0], given: 35

Re: In tests for Feline Leukemia Virus (FeLV), a serious disease [#permalink]  28 Feb 2012, 00:25
Choice E is the correct one.
_________________

Rules for posting in verbal gmat forum, read it before posting anything in verbal forum
Giving me + 1 kudos if my post is valuable with you

Senior Manager
Joined: 27 Jun 2012
Posts: 413
Followers: 23

Kudos [?]: 194 [0], given: 171

Re: In tests for Feline Leukemia Virus (FeLV), a serious disease [#permalink]  07 Jan 2013, 20:57
Argument states two issues - False positive and False negative results of tests. However the author suggests one issue over other (Say issue 2 over issue 1). We need to find out why Issue2 is more significant and Issue1 can be less of a priority.

Choice (E) correctly supports author's recommendation. That Issue 1 (false positive ) tests have same accuracy statistics, thus he recommends addressing issue2 (false negative tests)
_________________

Thanks,
PraPon

VOTE: vote-best-gmat-practice-tests-excluding-gmatprep-144859.html
Tough RCs: Passage1 | Passage2 | Passage3 | Passage4 | Passage5 | Passage6 | Passage7

Re: In tests for Feline Leukemia Virus (FeLV), a serious disease   [#permalink] 07 Jan 2013, 20:57
Similar topics Replies Last post
Similar
Topics:
In tests for pironoma, a serious disease, a false positive 7 29 Sep 2003, 03:50
In tests for pironoma, a serious disease, a false positive 6 11 Oct 2006, 09:20
In tests for pironoma, a serious disease, a false positive 9 25 Mar 2007, 12:16
In tests for pironoma, a serious disease, a false positive 5 02 Apr 2008, 14:54
In tests for pironoma, a serious disease, a false positive 0 14 Jul 2008, 21:48
Display posts from previous: Sort by

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

 Question banks Downloads My Bookmarks Reviews

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.