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A recent survey of all auto accident victims in Dole County [#permalink]
02 May 2008, 08:38
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A recent survey of all auto accident victims in Dole County found that, of the severely injured drivers and front-seat passengers, 80 percent were not wearing seat belts at the time of their accidents. This indicates that, by wearing seat belts, drivers and front-seat passengers can greatly reduce their risk of being severely injured if they are in an auto accident. The conclusion above is not properly drawn unless which of the following is true?
(A) Of all the drivers and front-seat passengers in the survey, more than 20 percent were wearing seat belts at the time of their accidents. (B) Considerably more than 20 percent of drivers and front-seat passengers in Dole County always wear seat belts when traveling by car. (C) More drivers and front-seat passengers in the survey than rear-seat passengers were very severely injured. (D) More than half of the drivers and front-seat passengers in the survey were not wearing seat belts at the time of their accidents. (E) Most of the auto accidents reported to police in Dole County do not involve any serious injury.
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Re: CR - auto accidents [#permalink]
02 May 2008, 08:58
i like D.. saravalli wrote: A recent survey of all auto accident victims in Dole County found that, of the severely injured drivers and front-seat passengers, 80 percent were not wearing seat belts at the time of their accidents. This indicates that, by wearing seat belts, drivers and front-seat passengers can greatly reduce their risk of being severely injured if they are in an auto accident. The conclusion above is not properly drawn unless which of the following is true?
(A) Of all the drivers and front-seat passengers in the survey, more than 20 percent were wearing seat belts at the time of their accidents. (B) Considerably more than 20 percent of drivers and front-seat passengers in Dole County always wear seat belts when traveling by car. (C) More drivers and front-seat passengers in the survey than rear-seat passengers were very severely injured. (D) More than half of the drivers and front-seat passengers in the survey were not wearing seat belts at the time of their accidents. (E) Most of the auto accidents reported to police in Dole County do not involve any serious injury.
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Re: CR - auto accidents [#permalink]
02 May 2008, 09:28
D looks correct. Others dont look relevant to argument.
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Re: CR - auto accidents [#permalink]
02 May 2008, 19:36
saravalli wrote: A recent survey of all auto accident victims in Dole County found that, of the severely injured drivers and front-seat passengers, 80 percent were not wearing seat belts at the time of their accidents. This indicates that, by wearing seat belts, drivers and front-seat passengers can greatly reduce their risk of being severely injured if they are in an auto accident. The conclusion above is not properly drawn unless which of the following is true?
(A) Of all the drivers and front-seat passengers in the survey, more than 20 percent were wearing seat belts at the time of their accidents. (B) Considerably more than 20 percent of drivers and front-seat passengers in Dole County always wear seat belts when traveling by car. (C) More drivers and front-seat passengers in the survey than rear-seat passengers were very severely injured. (D) More than half of the drivers and front-seat passengers in the survey were not wearing seat belts at the time of their accidents. (E) Most of the auto accidents reported to police in Dole County do not involve any serious injury. D for sure. If D does not hold good..then the argument will fall apart
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Re: CR - auto accidents [#permalink]
04 May 2008, 01:03
Wow, what a toughie +1 for you saravalli.
Conclusion : by wearing seat belts, drivers and front-seat passengers can greatly reduce their risk of being severely injured if they are in an auto accident.
The moment they start talking about risk, I start thinking probabilities and statistics. So how can we conclude that the probability will reduce ? Simple - by looking at the total number who had accidents and were wearing seatbelts which is option D.
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Re: CR - auto accidents [#permalink]
04 May 2008, 05:43
The right answer is A. A. It supports conclusion. More than 20% of drivers all the drivers and front-seat passengers accounts only for 20% of those who was severely injured. B. Out of scope. We don't care about all the time. The question is whether or not they were wearing seat belts at the time of their accidents. C. Out of scope. We are not discussing rear seats. D. Neutral. Actually it tells nothing about risk. To make this clear let check by real numbers: 1. let's assume that 51% of the drivers and front-seat passengers in the survey were not wearing seat belts at the time of their accidents. That definitely supports conclusion: 51% of all the drivers and front-seat passengers accounts for 80% of those who was severely injured. 2. let's assume that 99% of the drivers and front-seat passengers in the survey were not wearing seat belts at the time of their accidents. (we can assume this, because 99% is obviously more than the half). That definitely contradicts conclusion: 99% of all the drivers and front-seat passengers accounts for only 80% of those who was severely injured. E. Out of scope. We are not discussing the absolute value of risk of being severely injured. Just ways to reduce this risk.
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Re: CR - auto accidents [#permalink]
04 May 2008, 18:43
glebushka : Through your answer your weakening the conclusion. Where as the question is asking for the assumption that supports the argument. Hope I have understood the question correctly ?
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Re: CR - auto accidents [#permalink]
05 May 2008, 00:02
bhatiagp wrote: glebushka : Through your answer your weakening the conclusion. Where as the question is asking for the assumption that supports the argument. Hope I have understood the question correctly ? Actually, A supports conclusion. Reread my explanation for A, it seems to be pretty clear.
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Re: CR - auto accidents [#permalink]
05 May 2008, 02:15
A is clear choice.Lets say 100 is the sample size of all the drivers and front-seat passengers in the survey.Lets say 70 were severly injured in the accident ,so 80% of 70 ie 56 were not wearing seat belts .but other 44 (14+30) should be wearing seat belts for the conclusion to be true .44 is more than 20% of 100,so A is good .The important point to note is stem and answer are taling about different sample of people.
Rest other choices are out of scope or partially true
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Re: CR - auto accidents [#permalink]
05 May 2008, 06:16
i chose A too....whats the OA?
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Re: CR - auto accidents [#permalink]
05 May 2008, 09:25
Another for D.
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Re: CR - auto accidents [#permalink]
05 May 2008, 10:59
I agree that it's A but I had to REALLY think about it.
We know that off the people severly injured, 80% were not wearing a seatbelt.
We are trying to compare the odds of wearing a seatbelt to being severly injured.
So now we need to see how many people were wearing a seatbelt to see if it actually changes our odds. So to validate the conlusion we need the percentage of accident victims not wearing a seatbelt to be less than 80%.
A. does this by saying that the number of people wearing a seatbelt was more than 20% so therefore the number of people not wearing had to be less than 80%.
If 80% of the drivers were not wearing a seatbelt and 20% were, and the 80% of the drivers were seriously injured and 20% were not you haven't increased or decreased your chance by wearing a seatbelt.
ex. 100 people, 80 wearing seatbelt and 20 aren't. Let's say 50 people are seriously injured, so 40 of those were not wearing a seatbelt while 10 were.
40/80 = .5 10/20 = .5
You have the same odds.
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Re: CR - auto accidents
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05 May 2008, 10:59
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