Weakening the argument

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Weakening the argument

by prateek9567 » Sat Jul 26, 2014 10:36 am
Automobile Dealer's Advertisement:
The Highway Traffic Safety Institute reports that the PZ 1000 has the fewest injuries per accident of anycar in
its class. This showsthat the PZ 1000 is one of the safest cars available today.
Which of the following, if true, most seriously weakens the argument in the advertisement?
(A) The HighwayTraffic Safety Institute report listedmany cars in other classes that hadmore injuries per
accident than did the PZ 1000.
(B) In recent years many more PZ 1000s have been sold than have any other kind of car in its class.
(C) Cars in the class to which thePZ 1000 belongs are more likely to be involved in accidents than are other
typesof cars.
(D) The difference between the number of injuries per accident for the PZ 1000 and that for other cars in its
class is quite pronounced.
(E) The Highway Traffic Safety Institute issues reports only once a year.

OA: C

D says that the number of accidents in PZ1000 is very high as compared to vehicles in the same class. This makes PZ1000 less safe. Hence the argument is weaken. But the official guide says that this strengthens the argument to some extent.

Can someone please explain why is D wrong ?

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by GMATinsight » Sat Jul 26, 2014 12:38 pm
This is not the right thread to post this question.

You should be posting it in CR Thread.
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by [email protected] » Sat Jul 26, 2014 7:12 pm
Hi prateek9567,

This CR prompt requires that you really note the wording/details. We're asked to WEAKEN the argument, so we need to understand the logic involved and then attack that logic in some way.

The Facts:
-The PZ1000 car has the fewest INJURIES PER ACCIDENT of any car IN ITS CLASS.

The Conclusion:
-The PZ1000 is one of the SAFEST CARS available today.

The Logic:
The author is using "injuries per accident" as a measure of "safety", so having the FEWEST injuries per accident in ITS CLASS of car gives us a way to measure the safety of the PZ1000 in ITS CLASS. The conclusion tells us that the PZ1000 is one of the SAFEST CARS available today, which is a statement that involves ALL CARS, not just the ones in this class. For this conclusion to hold true, we have to assume that most (if not all) of the OTHER CARS in the OTHER CLASSES have a higher ratio of injuries per accident than the PZ1000.

We're asked to WEAKEN the logic, so we're probably looking for an answer that compares the PZ1000 to cars in OTHER CLASSES in some way that would imply that OTHER CLASSES of cars were SAFER than the PZ1000. The only answer that matches is C.

Answer D tells us that the number of injuries per accident for the PZ1000 is significant compared to the number of injuries per accident for OTHER CARS IN ITS CLASS. From the prompt, we already knew that the PZ1000 was safest in its class. Answer D confirms that information, and even implies that that the PZ1000 is much safer than other cars IN ITS CLASS. Since we're looking to WEAKEN the logic, this answer does not help.

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by UmangMathur » Sun Jul 27, 2014 5:51 am
prateek9567 wrote:Automobile Dealer's Advertisement:
The Highway Traffic Safety Institute reports that the PZ 1000 has the fewest injuries per accident of anycar in
its class. This showsthat the PZ 1000 is one of the safest cars available today.
Which of the following, if true, most seriously weakens the argument in the advertisement?
(A) The HighwayTraffic Safety Institute report listedmany cars in other classes that hadmore injuries per
accident than did the PZ 1000.
(B) In recent years many more PZ 1000s have been sold than have any other kind of car in its class.
(C) Cars in the class to which thePZ 1000 belongs are more likely to be involved in accidents than are other
typesof cars.
(D) The difference between the number of injuries per accident for the PZ 1000 and that for other cars in its
class is quite pronounced.
(E) The Highway Traffic Safety Institute issues reports only once a year.

OA: C

D says that the number of accidents in PZ1000 is very high as compared to vehicles in the same class. This makes PZ1000 less safe. Hence the argument is weaken. But the official guide says that this strengthens the argument to some extent.

Can someone please explain why is D wrong ?
Point D says The difference between the number of injuries per accident for the PZ 1000 and that for other cars in its class is quite pronounced.

It no where says that number of accidents in PZ1000 is hign. Point D could either mean that the number of accidents in PZ1000 is very high or it could mean that the number of accidents of the vehicle in the same class is very high. The point only talks about the difference and not which one has higher number of accidents thus it might even strenghten the argument.

Hope it helps you.
Cheers!!!
Umang :-)

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by prateek9567 » Sun Jul 27, 2014 11:42 pm
UmangMathur wrote:
prateek9567 wrote:Automobile Dealer's Advertisement:
The Highway Traffic Safety Institute reports that the PZ 1000 has the fewest injuries per accident of anycar in
its class. This showsthat the PZ 1000 is one of the safest cars available today.
Which of the following, if true, most seriously weakens the argument in the advertisement?
(A) The HighwayTraffic Safety Institute report listedmany cars in other classes that hadmore injuries per
accident than did the PZ 1000.
(B) In recent years many more PZ 1000s have been sold than have any other kind of car in its class.
(C) Cars in the class to which thePZ 1000 belongs are more likely to be involved in accidents than are other
typesof cars.
(D) The difference between the number of injuries per accident for the PZ 1000 and that for other cars in its
class is quite pronounced.
(E) The Highway Traffic Safety Institute issues reports only once a year.

OA: C

D says that the number of accidents in PZ1000 is very high as compared to vehicles in the same class. This makes PZ1000 less safe. Hence the argument is weaken. But the official guide says that this strengthens the argument to some extent.

Can someone please explain why is D wrong ?
Point D says The difference between the number of injuries per accident for the PZ 1000 and that for other cars in its class is quite pronounced.

It no where says that number of accidents in PZ1000 is hign. Point D could either mean that the number of accidents in PZ1000 is very high or it could mean that the number of accidents of the vehicle in the same class is very high. The point only talks about the difference and not which one has higher number of accidents thus it might even strenghten the argument.

Hope it helps you.
Hello

My confusion is: no of accidents of PZ1000 - no of accidents of other cars in same class = high. This means no of accidents of PZ1000 > no of accidents of other cars in same class. Hence pz1000 is an unsafe car.

Otherwise the sentence should be difference between accidents of cars of the same class and accidents in PZ1000 is significant. Then I would agree with the sentence.

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by UmangMathur » Tue Jul 29, 2014 7:35 am
prateek9567 wrote:
UmangMathur wrote:
prateek9567 wrote:Automobile Dealer's Advertisement:
The Highway Traffic Safety Institute reports that the PZ 1000 has the fewest injuries per accident of anycar in
its class. This showsthat the PZ 1000 is one of the safest cars available today.
Which of the following, if true, most seriously weakens the argument in the advertisement?
(A) The HighwayTraffic Safety Institute report listedmany cars in other classes that hadmore injuries per
accident than did the PZ 1000.
(B) In recent years many more PZ 1000s have been sold than have any other kind of car in its class.
(C) Cars in the class to which thePZ 1000 belongs are more likely to be involved in accidents than are other
typesof cars.
(D) The difference between the number of injuries per accident for the PZ 1000 and that for other cars in its
class is quite pronounced.
(E) The Highway Traffic Safety Institute issues reports only once a year.

OA: C

D says that the number of accidents in PZ1000 is very high as compared to vehicles in the same class. This makes PZ1000 less safe. Hence the argument is weaken. But the official guide says that this strengthens the argument to some extent.

Can someone please explain why is D wrong ?
Point D says The difference between the number of injuries per accident for the PZ 1000 and that for other cars in its class is quite pronounced.

It no where says that number of accidents in PZ1000 is hign. Point D could either mean that the number of accidents in PZ1000 is very high or it could mean that the number of accidents of the vehicle in the same class is very high. The point only talks about the difference and not which one has higher number of accidents thus it might even strenghten the argument.

Hope it helps you.
Hello

My confusion is: no of accidents of PZ1000 - no of accidents of other cars in same class = high. This means no of accidents of PZ1000 > no of accidents of other cars in same class. Hence pz1000 is an unsafe car.

Otherwise the sentence should be difference between accidents of cars of the same class and accidents in PZ1000 is significant. Then I would agree with the sentence.
Hi,

I believe, your usage of the word difference is wrong. I can write, "There's a huge difference between my salary and Bill Gates's salary" and I can even write "There's a huge difference between Bill Gates's salary and my salary". Both would mean the same and Bill Gates's salary won't decrease in either of the cases... :-)

The word "difference" just compares the succeeding nouns.
Cheers!!!
Umang :-)

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