大全2-14

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.

(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.（A）

(E) Most of the auto accidents reported to police in Dole County do not involve any serious injury. Why is not D but is A I don't find any evidence that A is correct answer...IF A is right answer why is not??please help help me...

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lonelyplanet发表于 2008-10-1 19:49 | 只看该作者

A is right b/c if there are less than 20% of people wearing seat belts, then the fact that 80% of the people not wearing seat belt are severely injured doesn't prove the difference of wearing or not wearing a seat belt.

D is not right b/c we don't need to have more than 50% of the drivers and front-seat passengers to make the argument valid. Remember the question:

The conclusion above is not properly drawn unless which of the following is true?

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ShawnHuHu发表于 2008-10-2 07:54 | 只看该作者

I understand..but why B and C isn't right   thanks to your reply...

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lonelyplanet发表于 2008-10-2 20:04 | 只看该作者

C is not right b/c it is irrelevant.

B is not right b/c it is just a repeatition of A, but instead makes it less valid.

Give you an example: if there are 200 students in your school, then you tell people that there are more than 199 students there. That is a good statement. However, if you say there are a lot more than 199 students, you are not wrong, but it is not as accurate at the first statement. Do that make sense?

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