Reviewing historical data, medical researchers in California found tha

Question

Reviewing historical data, medical researchers in California found that counties with the largest number of television sets per capita have had the lowest incidence of a serious brain disease, mosquito-borne encephalitis. The researchers have concluded that people in these counties stay indoors more and thus avoid exposure to the disease.

The researchers conclusion would be most strengthened if which of the following were true?

(A) Programs designed to control the size of disease-bearing mosquito populations have not affected the incidence of mosquito borne encephalitis.

(B) The occupations of county residents affect their risk of exposure to mosquito-borne encephalitis more than does television-watching.

(C) The incidence of mosquito-borne encephalitis in counties with the largest number of television sets per capita is likely to decrease even further.

(D) The more time people in a county spend outdoors, the greater their awareness of the dangers of mosquito-borne encephalitis.

(E) The more television sets there are per capita in a county, the more time the average county resident spends watching television.

KarishmaB · Accepted Answer

Counties with largest number of tv sets per capita (say, 3 TVs per person) have lowest incidence of mosquito borne Ence.

Conclusion: People in these counties stay indoors more and thus avoid exposure to the disease.

There is a gap here. How does having more TVs lead to staying indoors more? Whether I have 1 TV or 3 TVs, I can watch only 1 at a time. Just because I have 3 for myself, would I watch TV for thrice the hours? No. I just want one in my living, one in my bedroom and one in my kitchen - just to ensure that when I want to watch, I cans it anywhere and watch. More TVs means more convenience but doesn't imply more TV watching hrs.

(A) Programs designed to control the size of disease-bearing mosquito populations have not affected the incidence of mosquito borne encephalitis.

The smaller population of mosquitoes has no impact on incidence. This is irrelevant. We want to see how the "increase in the number of TVs per capita" impacts incidence.

(B) The occupations of county residents affect their risk of exposure to mosquito-borne encephalitis more than does television-watching.

This takes away some of the punch of the conclusion. That occupations affect risk of exposure more than TV. Does it make TV a stronger reason or staying indoors and avoiding mosquitoes? No. So not a strengthener.

(C) The incidence of mosquito-borne encephalitis in counties with the largest number of television sets per capita is likely to decrease even further.

Why would the incidence in these countries decrease even further? Is there another factor at play here in these countries because of which the incidence is continuing to decrease? We don't know. Not a strengthener.

(D) The more time people in a county spend outdoors, the greater their awareness of the dangers of mosquito-borne encephalitis.

This says that staying outdoors increase awareness. That would reduce incidence. This is opposite to what the conclusion is saying.

(E) The more television sets there are per capita in a county, the more time the average county resident spends watching television.

This tells us that more TVs actually does mean more TV watching hours. Well, then it makes sense that they stay more indoors and hence reduce the incidence of mosquito bites. It strengthens our conclusion.

Answer (E)

vaibhavtripathi · Answer

We have 2 facts here. 
 1:  "County A has maximum number of TVs"
 2:  "Residents of county A stay indoors, thus are not exposed to the mosquito-bites".

Suppose county A is ghost haunted and the fear keeps the people indoors, in that case TV sets have nothing to do with people not getting mosquito-bites. So what we need is a way to connect the two facts;  1  and  2 .
Lets analyze the options.

(A) Programs designed to control the size of disease-bearing mosquito populations have not affected the incidence of mosquito borne encephalitis.
  OK, so we know the program sucked so far as the "mosquito borne encephalitis" is concerned, but what about TV sets? You are not saying anything about that. Rejected.  
(B) The occupations of county residents affect their risk of exposure to mosquito-borne encephalitis more than does television-watching.
  So what you are saying is that its the job that protected people and not the TV. You are actually weakening our argument. Rejected.  
(C) The incidence of mosquito-borne encephalitis in counties with the largest number of television sets per capita is likely to decrease even further.
  Very good, but what role are TV sets playing in that? Neither strengthen nor weaken. Rejected.  
(D) The more time people in a county spend outdoors, the greater their awareness of the dangers of mosquito-borne encephalitis.
  So what you are telling us is, if people stayed outdoor they'd be safer than otherwise? Weakening our argument. Rejected.  
(E) The more television sets there are per capita in a county, the more time the average county resident spends watching television.
  You, sir, just provided the link that we in the GMATClub were looking for. You the man!

NonPlus · Answer

We have to strengthen the conclusion:
==>  People in these counties stay indoors more and thus avoid exposure to the disease. 
given that:
Counties with the largest number of television sets per capita have had the lowest incidence of a serious brain disease, mosquito-borne encephalitis.

Given that:
Linkage 1: Largest number of television sets --> Lowest incidence of a serious brain disease
Author has concluded that:
Linkage 2: Stay indoors --> Avoid exposure to disease
Here, we don't have connection between the television sets and staying indoors. Hence, any answer choice that can create a linkage between Linkage 1 and 2 will be the correct answer choice.

(A) Programs designed to control the size of disease-bearing mosquito populations have not affected the incidence of mosquito borne encephalitis.
 Controlling the size of populations has no bearing on television sets being responsible for staying indoors.   Irrelevant 
(B) The occupations of county residents affect their risk of exposure to mosquito-borne encephalitis more than does television-watching.
 This choice weakens the Linkage - 1.   Opposite 
(C) The incidence of mosquito-borne encephalitis in counties with the largest number of television sets per capita is likely to decrease even further.
 So, incidence of disease is going to decrease because of other factors.   Incorrect 
(D) The more time people in a county spend outdoors, the greater their awareness of the dangers of mosquito-borne encephalitis.
 If staying outside increase awareness, why stay indoors.   Opposite 
(E) The more television sets there are per capita in a county, the more time the average county resident spends watching television.
 This choice establishes the link between television sets and staying indoors. The more time resident spends watching television, the more time they'll stay indoors.   Correct

nitesh50 · Answer

HI  VeritasKarishma

I could cut down to option A and Option E for a final pick.
I agree that option E is a better choice, but I feel Option A is also strengthing the conclusion to certain extent.
If we are saying that a certain cause has not lead to a particular effect, doesn't it strength the conclusion that Staying indoors has led to decrease in the diseases.
Basically what I am saying is they have eliminated a third cause.

Am I correct in my analysis?

Regards
Nitesh

KarishmaB · Answer

Nitesh, I understand what you are saying but note that our argument talks about "incidence rate in counties with more TVs" vs "incidence rate in counties with fewer TVs". Why is the incidence rate lower in counties with fewer TVs?

Option (A) talks about a program run (in particular counties or all counties, we don't know) to control mosquito population. We are also told that this program failed. Does this knowledge impact our argument at all? No. We want to find why the incidence is low in more TVs counties than in fewer TVs counties. Is it really because people spend more time watching TV indoors in these counties? Option (E) gives us this information.

In some cases, eliminating a cause could strengthen causality between two other elements. Think about it - if the outcome could be affected by a limited number of possible causes and you are flipping between two, removing one makes it more likely for the other to happen. But eliminating one factor in a situation that could be caused by many factors doesn't add much to the strength of another factor. What one needs to do in each case is a matter of judgement but in every GMAT question, it will be clear what is acceptable and what is not. There will be pressing reasons to accept/eliminate an option. If you feel a bit lost sometimes, try evaluating from the standpoint of a debate. You have your side to present. When the opponent presents a point, does it weaken your situation or not? Or when you present an additional point, does it strengthen your situation?

KarishmaB · Answer

Note that in our argument we are comparing the incidence of Ence in some specific counties (with max per capita no of TVs) to the incidence in other counties.
Option (A) talks about such programs in general. If they were implemented across counties and had no impact, it doesn't help in comparing A counties with B counties and establishing that more TVs is the cause of lower incidence of Ence in these counties. Hence, option (A) is irrelevant to our argument.
Even if we tried to implement the programs in only specific counties, it makes little sense to do it in those with the max per capita no of TVs. The option would not be very sensible in that case.

BhavyaKannan · Answer

Isnt option B the better choice here as it suggests that the more people stay in watching TV, the lower is the rate of exposure to mosquitoes so the chances of them contracting diseases are lower?

CrackverbalGMAT · Answer

Hi Bhavya

The question stimulus draws a conclusion about the residents' exposure to mosquito-borne encephalitis based on a fact about TV ownership. In order to strengthen the conclusion, we need something that connects TV ownership to staying indoors.

Option (B) states that the occupations of the county's residents affect their exposure to mosquito-borne encephalitis more than TV watching. This does not provide any connection between TV ownership and staying indoors but speaks more about the relative impacts of TV watching and the occupations on exposure to the disease. Hence this does not impact the conclusion in any way. If at all, it only weakens the link by mentioning a factor that has a greater impact on exposure to the disease.

Hope this helps.

Kritisood · Answer

Hi! Isnt E more of an assumption than strengthener?

gvij2017 · Answer

Hello Ma'm!

What I observed in such strengthening and weakening CR problem is that
1. When it is specifically mentioned that I need to strengthening and weakening the conclusion, then I just need to concentrate over conclusion. I should accept the reasoning/premises true as given.
2. It is totally different when question stem ask you to weaken or strengthen the argument and conclusion or particular statement.
Sometime we consider third factor/information to select the correct choice but that doesn't help always.
In this CR problem, lower indicates the comparison of California and Others counties.

From above analysis E fits in and A is out.

Please let me know something wrong I said so that I can clear my concept.

muky · Answer

I chose A because of the following reasoning:

Assumed this is a causation question i.e staying indoors leads to reduced cases of the disease. That said, any answer choice that concretes the relationship is super. Answer choice A states that other control measures have not affected the disease incidences in no way thereby giving room for the original causation relationship. I eliminated answer choice E because it restates the assumption that is already given in the passage.

Please assist on the law in my reasoning

Nipungupta9081 · Answer

Hey  muky  , this is a strengthening questioning so you need to use the things given in the question .

Option A - Programs designed to control the size of disease-bearing mosquito populations have not affected the incidence of mosquito borne encephalitis. - IRRELEVANT the question never talks about the population of the mosquito .

Option E - The more television sets there are per capita in a county, the more time the average county resident spends watching television. - which strengthens the claim in the premise - counties with the largest number of television sets per capita have had the lowest incidence of a serious brain disease, mosquito-borne encephalitis.

Hope this helps !! ?

CEdward · Answer

Reviewing historical data, medical researchers in California found that counties with the largest number of television sets per capita have had the lowest incidence of a serious brain disease, mosquito-borne encephalitis. The researchers have concluded that people in these counties stay indoors more and thus avoid exposure to the disease.

The researchers conclusion would be most strengthened if which of the following were true?

(A)  Programs designed  to control the size of disease-bearing mosquito populations have not affected the incidence of mosquito borne encephalitis.
This is irrelevant.

(B) The occupations of county residents affect their risk of exposure to mosquito-borne encephalitis more than does television-watching.
Arguably weakens...takes the focus away from tv watching/staying indoors. OUT.

(C) The incidence of mosquito-borne encephalitis in counties with the largest number of television sets per capita is likely to decrease even further.
Tempting trap choice...I eliminated this one b/c of 'likely to decrease even further' ...there's no certainty ...so perhaps it doesn't actually decrease?

(D) The more time people in a county spend outdoors, the greater their awareness of the dangers of mosquito-borne encephalitis.
'awareness' is another factor that could stave off disease...this weakens. A proper strengthened would eliminate awareness as a factor.

(E) The more television sets there are per capita in a county, the more time the average county resident spends watching television.
Correct. This ties the argument together and makes clear for us what the role of tv is in the passage.

RohitSaluja · Answer

Hi  GMATNinja   GMATNinjaTwo  can you please help here, your time would be appreciated.

I was able to cut it down to A/E. The conclusion of argument is  people in these counties stay indoors more and thus avoid exposure to the disease  . Now author is implying that "staying indoors" i.e. the cause have an effect of "avoiding exposure to the disease"

If we look at option A, it eliminates other causes of producing the effect, so isnt it strengthning the argument by eliminating other likely causes?. Though I agree option E tell us that indeed people do stay indoors in the country, and thus our conclsuion can be strengthned by this option as well.

My question is how do we pick the best option for this one?

Appreciate in advance!

VerbalBot · Answer

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.

Reviewing historical data, medical researchers in California found tha

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

Reviewing historical data, medical researchers in California found tha

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