Bicycle safety expert

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Bicycle safety expert

by georgepaul0071987 » Thu Oct 13, 2011 10:24 am
Bicycle Safety expert : Bicycling on the left half of the road is much more likely to lead to collisions with automobiles than is bicycling on the right . After all , in three different studies of bicycle-automobile collisions , the bicyclist was riding on the left in 15,17 and 25 percent of the cases respectively .

Skeptic : But in places where a comparatively high percentage of bicyclists used to ride on the left , there was suprisingly little decrease in collisions between bicyclists and automobiles after bicycling on the left was made illegal .

One reason the strength of the bicycle safety expert's argument cannot be evaluated is that

(A) The statistics cited in support of the conclusion is that bicycling on the left is more likely to lead to collisions with automobiles already pressupose the truth of the conclusion

(B) The statistics it cites do not include the percentage of bicycling that took place on the left

(C) No statistics are provided on the proportion of bicycle accidents that are due to bicycle automobile collisions .

(D) Bicycling on the left is singled out for criticism without consideration of the other bicycling practices that are unsafe

(E) It does not distinguish between places in which bicycling on the left is legal and places in which it is illegal .

Please give me explanations and not just your answer .

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by CappyAA » Thu Oct 13, 2011 11:38 am
IMO B

The bicycle safety expert cites that biking on the left is much more likely to result in a collision than biking on the right. She points to three studies as evidence that say that in collisions, bikers were riding on the left in 15, 17, and 25% of cases. However, she gives no evidence as to what percentage of the time that the bikers were riding on the left. If the bikers were riding on the left much of the time, we would expect a higher percentage of collisions to take place on the left.
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by garima99 » Thu Oct 13, 2011 11:48 am
+1 for B

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by parul9 » Sat Oct 15, 2011 10:22 am
I also think it's B.

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by David@VeritasPrep » Sat Oct 15, 2011 5:55 pm
OA is B.

This is an LSAT question from June 1997, the second logical reasoning section question #21.

CappyAA has given us a very good explanation here.

I would call this an example of a more frequent type of question on the GMAT called "most useful to know." I know it does not say "most useful to know" but you are looking for the information that is needed in order to evaluate the conclusion.

With a "most useful to know" question we are looking for the fact that would be able to tell us whether we have a good conclusion or not.

In this case, if we knew what percentage of people cycle on the left then we would know how impressive the 15, 17, and 25% statistics are. If we find that only 5% of people cycle on the left then this level of collisions would be high. If more than 25% cycle on the left then the number of collisions is low.
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by vikram4689 » Sat Apr 07, 2012 9:23 pm
Thanks David, can you provide response to other options as well. I am find it difficult to comprehend them.
AND is the SKEPTIC's argument is given only to confuse as it does not have any relevance in finding the correct answer

Also, where can i find more questions of this type
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by [email protected] » Wed Apr 11, 2012 2:27 am
One reason the strength of the bicycle safety expert's argument cannot be evaluated is that:


Firstly I did not understand the question at all...

Cannot be evaluated means is it overall a strengthen question or a weaken question...

I thought it to be a strengthen question and not something else...

But I guess I was wrong... Somebody please explain
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by ronnie1985 » Wed Apr 11, 2012 9:45 am
IMO (B)
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by David@VeritasPrep » Wed Apr 11, 2012 9:59 am
amit and vikram -

The wording of this question "One reason the strength of the bicycle safety expert's argument cannot be evaluated is that" should indicate to you that there is more that we need to know. That makes this a Most Useful to Know type of question. Such questions are pretty common. In the recent Official Guide 13th Edition there are 10 of these questions, including 2 new questions. This question type is considered to be difficult because it requires a little creative thinking on the part of the test-taker.

Let me give an example,if I were to say, "There is a new Integrated Reasoning section coming in June, but you should not be too concerned about it" what would you you need to know? Perhaps how much the Integrated Reasoning counts toward your overall score. If it counts highly toward your score then my conclusion is not well-supported. Yet if it does not contribute to the 200-800 score at all (and this is in fact the case) then the conclusion is supported. That is the essence of a Most Useful to Know, the information supplied will either strengthen or weaken, depending on what that information turns out to be.

For the question at hand, the conclusion is "Bicycling on the left half of the road is much more likely to lead to collisions with automobiles than is bicycling on the right" and the evidence given is that "in three different studies of bicycle-automobile collisions, the bicyclist was riding on the left in 15,17 and 25 percent of the cases respectively."

Now when you give me these facts I immediately want more information, because the conclusion does not seem to be very well supported here. Why would they conclude that cycling on the LEFT is more dangerous when only 15 to 25 percent of the accidents took place with cyclists on that side?? If seems like the left must be safer if 4 accidents take place when cycling on the right for each one on the left. There must be something we do not know.

The information that we are missing is "What percentage of cycling takes place on the left?" If 90% of cyclists are on the left side and 25% or less of the accidents are on that side then the conclusion fails. Cycling on the left is not more dangerous. But if we find out that only 2% of cycling is on the left and 15 to 25% of the accidents are the result then, yes, the conclusion is well-supported, cycling on the left is dangerous. This is just what choice B indicates.

Vikram - the skeptic is there to help you think about what information might be missing. He even mentions "percentage of bicyclists ride on the left" so that might give you a hint...
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by David@VeritasPrep » Wed Apr 11, 2012 10:10 am
Vikram -

There really is no hope for any of the other choices. Answer Choice A takes many words to indicate what is known as circular reasoning. This is a flaw where the conclusion and the evidence are the same. A famous example is "we should all pay the same amount for coffee in the office, because, although there are other ideas offered, each paying the same amount is the best way." As you see the conclusion is the same as the evidence.

Choice C is not relevant. If you give a good reading of the conclusion - and if you remember, as we say here at Veritas, that "Conclusion is King" you will note that the conclusion says "Bicycling on the left half of the road is much more likely to lead to collisions with automobiles than is bicycling on the right" so we are discussing ONLY collisions between bicycles and autos so it does not matter what proportion of accidents are from other causes.

Choice D is beside the point. I would not even say that cycling on the left has been singled out for criticism, it is just stated that it leads to more collisions. Other practices are not relevant here.

Choice E is not needed either. We are not concerned here about what is legal and what is not. We are concerned about what causes more auto-bike collisions.

Hope it helps!
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by vikram4689 » Wed Apr 11, 2012 7:32 pm
Thanks David, can you please point out few more questions of this type.
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by conquistador » Sat Nov 07, 2015 10:18 am
David@VeritasPrep wrote:Vikram -

There really is no hope for any of the other choices. Answer Choice A takes many words to indicate what is known as circular reasoning. This is a flaw where the conclusion and the evidence are the same. A famous example is "we should all pay the same amount for coffee in the office, because, although there are other ideas offered, each paying the same amount is the best way." As you see the conclusion is the same as the evidence.

Choice C is not relevant. If you give a good reading of the conclusion - and if you remember, as we say here at Veritas, that "Conclusion is King" you will note that the conclusion says "Bicycling on the left half of the road is much more likely to lead to collisions with automobiles than is bicycling on the right" so we are discussing ONLY collisions between bicycles and autos so it does not matter what proportion of accidents are from other causes.

Choice D is beside the point. I would not even say that cycling on the left has been singled out for criticism, it is just stated that it leads to more collisions. Other practices are not relevant here.

Choice E is not needed either. We are not concerned here about what is legal and what is not. We are concerned about what causes more auto-bike collisions.

Hope it helps!
Hello david,

According to the solution and your explanation, Only B helps us evaluate the argument and others dont right?
but the question asks for one reason that cannot be evaluated. i.e., except question meaning 4 right one wrong answer. Please clarify my confusion.

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by DavidG@VeritasPrep » Wed Nov 11, 2015 8:33 am
Hello david,

According to the solution and your explanation, Only B helps us evaluate the argument and others dont right?
but the question asks for one reason that cannot be evaluated. i.e., except question meaning 4 right one wrong answer. Please clarify my confusion.
Not exactly. When the question asks for one reason why the argument cannot be evaluated, it's essentially asking for a missing piece, or flaw, in the argument. So we have the correct answer, which points to the piece missing from the argument, and four incorrect answers, which in this case, are not relevant to the argument.
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