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

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

Cats

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 549
Joined: Wed Jan 06, 2010 7:00 amFollowed by: 3 members
Thanked: 16 times
by ssgmatter » Tue Mar 30, 2010 6:56 am
The interstitial nucleus, a subregion of the brain's hypothalamus, is typically smaller for male cats than for female cats. A neurobiologist perFORMed autopsies on male cats who died from disease X, a disease affecting no more than .05 percent of male cats, and found that these male cats had interstitial nuclei that were as large as those generally found in female cats. Thus, the size of the interstitial nucleus determines whether or not male cats can contract disease X.

Which one of the following statements, if true, most seriously weakens the argument?

(A) No female cats have been known to contract disease X, which is a subtype of disease Y.

(B) Many male cats who contract disease X also contract disease Z, the cause of which is unknown.

(C) the interstitial nuclei of female cats who contact disease X are larger than those of female cats who do not contract disease X.

(D) Of 1,000 autopsies on male cats who did not contract disease X, 5 revealed interstitial nuclei larger than those of the average male cat.

(E) The hypothalamus is known not to be causally linked to disease Y, and disease X is a subtype of disease Y.

Please explain this is hieghts...

Regards
Phil
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Critical Reasoning |
Senior | Next Rank: 100 Posts
Posts: 51
Joined: Fri Mar 26, 2010 10:09 am

by aspirant2010 » Tue Mar 30, 2010 7:21 am
Is the answer D......
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 549
Joined: Wed Jan 06, 2010 7:00 amFollowed by: 3 members
Thanked: 16 times

by ssgmatter » Tue Mar 30, 2010 7:43 am
please explain i will post the OA asap

Regards,
Phil
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 182
Joined: Mon Apr 20, 2009 7:09 pmFollowed by: 1 member
Thanked: 1 times

by akahuja143 » Tue Mar 30, 2010 7:50 am
IMO D

Conclusion is based on evidence
a disease affecting no more than .05 percent of male cats, and found that these male cats had interstitial nuclei that were as large as those generally found in female cats.


If we can show that is not reliable or flawed then argument will fall apart

D does it

(D) Of 1,000 autopsies on male cats who did not contract disease X, 5 revealed interstitial nuclei larger than those of the average male cat.

5 out of 1000 is .05 % and let us know that this is common irrespective of the diseases
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 232
Joined: Sun Feb 28, 2010 10:47 pm
Thanked: 10 times

by Phirozz » Tue Mar 30, 2010 8:37 am
IMO E

A, B AND C can be easily eliminated.
now D, does the author saying anything about cats who do not contract disease X ? NO. So it neither weaken nor strengthen the argument

Now come to E, it is clearly attacking the conclusion. Since X is a subtype of disease Y, hypothalamus should link to Y as well but it does not. So it weaken the argument
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
GMAT Instructor
Posts: 1302
Joined: Mon Oct 19, 2009 2:13 pmFollowed by: 164 members
Location: Toronto
Thanked: 539 times
GMAT Score:800

by Testluv » Tue Mar 30, 2010 1:09 pm
recieved a pm.

Phirozz is correct.

When the author makes a causal argument, the author is making any one (or more) of the following assumptions:

a) that there isn't an alternative cause;
b) that it isn't a coincidence; and
c) that causality isn't reversed (although this applies only to simutltaneous rather than chronological correlation).

Of these three, by far the most common is a. The second most common is b. We can weaken the argument by attacking any one of these assumptions.

Here, choice E tells us that we are in "b": since the hypothalamus is KNOWN not to be causally linked to disease X, the statistics are just a coincidence. Thus, choice E clearly weakens the argument, and must be correct.

Because choice E matches our prediction, we should select it without worrying about choice D--on test day, we have to be confident.

But, while reviewing our performance, we should figure out why tempting wrong answers are wrong.

Choice D tells us that 5 percent of male cats had nuclei that were larger than the average male cat nuclei. But we are left wondering whether these nuclei are as large as female cat nuclei. Thus, choice D does not successfully weaken the argument.
Kaplan Teacher in Toronto
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 549
Joined: Wed Jan 06, 2010 7:00 amFollowed by: 3 members
Thanked: 16 times

by ssgmatter » Wed Mar 31, 2010 7:24 am
Thankyou Testluv for that such an exhaustive analysis.

Regards,
Phil
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 58
Joined: Tue Aug 26, 2008 9:42 am

by ru2008 » Wed Mar 31, 2010 8:30 am
Could you explain why A,B,C, E is wrong?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
GMAT Instructor
Posts: 1302
Joined: Mon Oct 19, 2009 2:13 pmFollowed by: 164 members
Location: Toronto
Thanked: 539 times
GMAT Score:800

by Testluv » Thu Apr 01, 2010 4:27 pm
ru2008 wrote:Could you explain why A,B,C, E is wrong?
Choices A and C are wrong because the author is making an argument about male cats not female cats. In other words, it is outside the scope of the author's argument. Thus, it cannot weaken this argument.

Choice B is wrong because we have no idea about how to evaluate the relevance of the correlation between disease X and disease Z. In other words, it is outside the scope.

I explained why choice D is wrong in my post above.

You are far better off analyzing the argument correctly, and predicting the correct answer, than you are figuring out why all of the wrong answers are wrong. However, when reviewing it is a great idea to articulate why wrong answers are wrong.
Kaplan Teacher in Toronto
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Senior | Next Rank: 100 Posts
Posts: 89
Joined: Thu Sep 03, 2009 5:06 amFollowed by: 1 member
Thanked: 14 times
GMAT Score:770

by prepgmat09 » Fri Jul 30, 2010 3:57 am
Testluv wrote:recieved a pm.

Phirozz is correct.

When the author makes a causal argument, the author is making any one (or more) of the following assumptions:

a) that there isn't an alternative cause;
b) that it isn't a coincidence; and
c) that causality isn't reversed (although this applies only to simutltaneous rather than chronological correlation).

Of these three, by far the most common is a. The second most common is b. We can weaken the argument by attacking any one of these assumptions.

Here, choice E tells us that we are in "b": since the hypothalamus is KNOWN not to be causally linked to disease X, the statistics are just a coincidence. Thus, choice E clearly weakens the argument, and must be correct.

Because choice E matches our prediction, we should select it without worrying about choice D--on test day, we have to be confident.

But, while reviewing our performance, we should figure out why tempting wrong answers are wrong.

Choice D tells us that 5 percent of male cats had nuclei that were larger than the average male cat nuclei. But we are left wondering whether these nuclei are as large as female cat nuclei. Thus, choice D does not successfully weaken the argument.
Hello Testluv, Thanks so much for the wonderful explanation.

However, I still have a doubt with choice D. Sometimes, an approach to weaken a cause and effect argument is to show that the effect is not there even when the cause is there. D is also doing that, although I agree that with D we are left wondering whether these nuclei are as large as female cat nuclei.

So, should we still consider this choice as "slightly weaken".
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1