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

It is currently 22 Sep 2014, 20:56

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Blood banks will shortly start to screen all donors for NANB

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 09 Aug 2006
Posts: 36
Followers: 0

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

GMAT Tests User
Blood banks will shortly start to screen all donors for NANB [#permalink] New post 21 Aug 2006, 20:26
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
Blood banks will shortly start to screen all donors for NANB hepatitis. Although the new screening tests are estimated to disqualify up to 5 percent of all prospective blood donors, they will still miss two-thirds of donors carrying NANB hepatitis. Therefore, about 10 percent of actual donors will still supply NANB-contaminated blood.

The argument above depends on which of the following assumptions?
(A) Donors carrying NANB hepatitis do not, in a large percentage of cases, carry other infections for which reliable screening tests are routinely performed.
(B) Donors carrying NANB hepatitis do not, in a large percentage of cases, develop the disease themselves at any point.
(C) The estimate of the number of donors who would be disqualified by tests for NANB hepatitis is an underestimate.
(D) The incidence of NANB hepatitis is lower among the potential blood donors than it is in the population at large.
(E) The donors who will still supply NANB-contaminated blood will donate blood at the average frequency for all donors.

Please kindly explain
Senior Manager
Senior Manager
avatar
Joined: 14 Jul 2005
Posts: 405
Followers: 1

Kudos [?]: 8 [0], given: 0

GMAT Tests User
 [#permalink] New post 21 Aug 2006, 20:48
I believe it is D

5% will be disqualified ... but 2/3rd will be missed..hence total is actually 15% for general population
Director
Director
avatar
Joined: 17 Jul 2006
Posts: 716
Followers: 1

Kudos [?]: 8 [0], given: 0

GMAT Tests User
 [#permalink] New post 22 Aug 2006, 02:54
It looks like D for the sAME reason.
Director
Director
User avatar
Joined: 28 Dec 2005
Posts: 761
Followers: 1

Kudos [?]: 8 [0], given: 0

GMAT Tests User
 [#permalink] New post 22 Aug 2006, 03:09
I think it is A. Assume a large percentage, say 80% of donors with NANB also have an infection X, which can be reliably screened. This means that 80% of the infected donors will be eliminated from the donation, reducing the percentage of actual infected donors from 10% to a lesser value.
VP
VP
avatar
Joined: 21 Mar 2006
Posts: 1136
Location: Bangalore
Followers: 2

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

GMAT Tests User
 [#permalink] New post 22 Aug 2006, 03:09
(A) Donors carrying NANB hepatitis do not, in a large percentage of cases, carry other infections for which reliable screening tests are routinely performed. - Good... Keep.
(B) Donors carrying NANB hepatitis do not, in a large percentage of cases, develop the disease themselves at any point. - Irrelevant. whether they do eventually develop the diease or not does not matter to us.(C) The estimate of the number of donors who would be disqualified by tests for NANB hepatitis is an underestimate. - this is an inference
(D) The incidence of NANB hepatitis is lower among the potential blood donors than it is in the population at large. - No mention of general population at all. Out of scope(E) The donors who will still supply NANB-contaminated blood will donate blood at the average frequency for all donors. - Frequency? what frequency? Out of scope

Note: You could also try the negation technique. Only negating A breaks the argument.
Senior Manager
Senior Manager
User avatar
Joined: 13 Jul 2006
Posts: 327
Followers: 1

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

GMAT Tests User
 [#permalink] New post 22 Aug 2006, 03:12
I think its (A)
Senior Manager
Senior Manager
User avatar
Joined: 13 Jul 2006
Posts: 327
Followers: 1

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

GMAT Tests User
 [#permalink] New post 22 Aug 2006, 03:13
Nd wat do u mean by the negation technique?
VP
VP
avatar
Joined: 21 Mar 2006
Posts: 1136
Location: Bangalore
Followers: 2

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

GMAT Tests User
 [#permalink] New post 22 Aug 2006, 03:28
sangarelli wrote:
Nd wat do u mean by the negation technique?


It is a (common) technique used for CR-assumption questions. Its quite simple and effective. You just 'negate' each answer one by one and see if the argument fails or not. If the argument fails, then the original statement is a necessary assumption for the argument to be valid. I'll explain with the above as an example.

A says: Donors carrying NANB hepatitis do not, in a large percentage of cases, carry other infections for which reliable screening tests are routinely performed.

Now let us negate A: - Donors carrying NANB hepatitis do, in a large percentage of cases, carry other infections for which reliable screening tests are routinely performed.

Now, if these donors who carried the NANB virus also carried other infections that could be reliably screened blood banks will not miss them out. Hence the argument fails. Thus A is a necessary assumption.
Intern
Intern
avatar
Joined: 09 Aug 2006
Posts: 36
Followers: 0

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

GMAT Tests User
 [#permalink] New post 22 Aug 2006, 04:12
kripalkavi,

Thanks a lot for your thourough explaination!
It's a tough one for me.
Manager
Manager
avatar
Joined: 22 Aug 2006
Posts: 57
Location: Moscow, Russia
Followers: 1

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

 [#permalink] New post 22 Aug 2006, 07:43
I disagree. I think it's E:

The stimulus basically tells us that there will be a new screening procedure with 33% hit rate

A. Out-o-scope If reliable tests for other diseases are in place both befoere and after the new test introduction (and this is what A sys), they should not affect the ratio of hepatitis donors turned away. Those screens against other diseases were there and they will still be thereafter the new test is in place, with their hit rates unchanged (nothing says those other procedureure's reliability will change). Therefore they will not affect the miss rate of the hepatitis test. Furthermore, we have a vague "large percentage" of cases modifier here (how large a number of hep cases they screen out) - and vagueness doesnt cut it here.

B. it's irrelevant if they develop the disease or not they are screened for being carriers

C. id it's an unsderestimate, it means the actual test has a higher hit rate and therfore disproves the conculision, while we are asked to do the opposite.

D. we know anothing about hep incidence among the general public- that fact is not involved in the author's main point about the test deficiency.

E. same as D, we know nothing about the rates at which they donate blood
_________________

________________________________
"Amicus Plato, sed magic amica veritas"

  [#permalink] 22 Aug 2006, 07:43
    Similar topics Author Replies Last post
Similar
Topics:
Blood banks will shortly start to screen all donors for NANB johnycute 10 08 Jun 2007, 21:53
Blood banks will shortly start to screen all donors for NANB mm007 5 15 Dec 2006, 11:49
Blood banks will shortly start to screen all donors for NANB prude_sb 4 04 Jun 2006, 07:40
Blood banks will shortly start to screen all donors for NANB rianah100 3 01 Dec 2005, 05:58
Blood banks will shortly start to screen all donors for NANB nakib77 3 01 Nov 2005, 03:42
Display posts from previous: Sort by

Blood banks will shortly start to screen all donors for NANB

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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®.