IMO its D. I'm counting on this choice by eliminating other choices.

italian7745 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.
-- This doesn't seem to be a necessary assumption. We know that 80% of severely injured drivers and front-seat passengers were not wearing seat-belts. This choice just say that remaining percent of drivers were wearing seat-belts which does not merely give support to the conclusion.
(B) Considerably more than 20 percent of drivers and front-seat passengers in Dole County always wear seat belts when traveling by car.
-- Again the same as A.
(C) More drivers and front-seat passengers in the survey than rear-seat passengers were very severely injured.
-- There is no point in talking about rear-seat passengers. The survey only considers the drivers and front-seat passengers.
(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.
-- This choice seems to be ideal. But i'm not able to justify this correct answer.
(E) Most of the auto accidents reported to police in Dole County do not involve any serious injury.
-- This choice is no way in support of the conclusion.

i think its A.
the first part of the argument explains that 80% drivers and front-seat passengers did not wear seat belts and were injured in the accident. However the conclusion is based on the people wearing seat belts. Assumption is that 20% are not injured because they are wearing seat belts, but this is not stated in the argument. Another reason for 20% to be safe could be the air bags. So i think A fills in the gap correctly.

Please post OA.

I was between A and D. Would go with A as it mentions the remaining percentage of the people who wear seat belts.

Please post the OA

Choice A is correct.

Hi Testluv,

Thanks for responding! I'm still not able to understand why B is correct. Is it because of the phrase "... always wear seat belts when traveling by car" in choice B?

Also, could you please help me understand why D is incorrect?

OA IS A

Yes, indeed the correct answer is choice A, and I was wrong in my first post.

The first sentence reads:

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.

The implication is that some victims were severely injured and other accident victims were injured but not severely.

The conclusion reads:
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.

So he is concluding that by wearing a seatbelt your risk of being severly injured from an automobile accident decreases. (not that your risk of being in an accident decreases!)

In order for him to be right that the risk of being severely injured decreases by wearing a seatbelt, there should be MORE non-seatbeltwearers in the severely injured group than there are in the ``regular`injured group. That is the fraction of those not wearing seatbelts should increase with the severity of the injury.

Then, choice A matches this insight.

Unfortunately, I did not give the argument much respect the first time I read it, and I just thought he was arguing that the risk of being involved in an injury-creaing accident in general increases if you are not wearing a seatbelt. Choice B is match for someone who went through the argument too quickly, and arrived at this likely misinterpretation.

To avoid confusion, I will delete my original post, in which I incorrectly stated that choice B was correct.

Thanks Testluv,

I clearly understand now. This is more tougher and trickier than i had actually thought of.