Evaluate Argument

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yvonne0923: Senior | Next Rank: 100 Posts; Posts: 96; Joined: Mon Mar 07, 2011 8:43 pmFollowed by: 1 member; Thanked: 1 times

by yvonne0923 » Tue Apr 26, 2011 2:01 pm

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 surprisingly 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 ore likely to lead to collisions with automobiles already presuppose 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 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.

______________________________________________________________________________
[spoiler]Answer:B[/spoiler]

I chose C first, since I'm still confusing about the number of 15,17,and 25 which are provided from the argument.

Thanks,
Yvonne

Source: Beat The GMAT — Critical Reasoning | Tue Apr 26, 2011 2:01 pm

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e-GMAT: GMAT Instructor; Posts: 645; Joined: Mon Jul 26, 2010 12:42 pmFollowed by: 227 members; Location: US; Thanked: 527 times

by e-GMAT » Tue Apr 26, 2011 2:43 pm

This is a good question:OA is B as stated

The argument draws the conclusion that riding on the left is more dangerous based on three studies cited in the argument. Nowhere does it say that what percentage of time or what percentage of bicyclists were driving on the left.

Lets take the study (as an example) that states that in 15% of the cases the bicyclist riding in the left. The argument only holds true if less than 15% of the bicycling was done on the left side. This is because, if more than 15% of the bicycling was done on the left (lets assume 50%) then riding on left is actually safer which refutes the conclusion. Choice B exposes this omission and is the correct choice.

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mundasingh123: Legendary Member; Posts: 2330; Joined: Fri Jan 15, 2010 5:14 amFollowed by: 26 members; Thanked: 56 times

by mundasingh123 » Wed Apr 27, 2011 2:12 am

yvonne0923 wrote: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 surprisingly 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 ore likely to lead to collisions with automobiles already presuppose 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 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.

______________________________________________________________________________
[spoiler]Answer:B[/spoiler]

I chose C first, since I'm still confusing about the number of 15,17,and 25 which are provided from the argument.

Thanks,
Yvonne

Where did u get this question ?

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champmag: Master | Next Rank: 500 Posts; Posts: 234; Joined: Tue Feb 22, 2011 5:02 amFollowed by: 3 members; Thanked: 5 times

by champmag » Wed Apr 27, 2011 2:43 am

IMO B

The argument of the bicycle safety expert states the percentage of cases in which bicyclist was riding on the left when the accident took place.

Taking the bigger picture, how many percentage of bicyclists from all the bicyclists that ride on the streets were actually riding on the left? This figure is not mentioned in the argument. It might be a possibility that the percentage of byscylists riding on the right are more than those riding on the left. This possibility can weaken the conclusion.

So B fits perfectly.

mundasingh123: Legendary Member; Posts: 2330; Joined: Fri Jan 15, 2010 5:14 amFollowed by: 26 members; Thanked: 56 times

by mundasingh123 » Wed Apr 27, 2011 3:14 am

champmag wrote:IMO B

The argument of the bicycle safety expert states the percentage of cases in which bicyclist was riding on the left when the accident took place.

Taking the bigger picture, how many percentage of bicyclists from all the bicyclists that ride on the streets were actually riding on the left? This figure is not mentioned in the argument. It might be a possibility that the percentage of byscylists riding on the right are more than those riding on the left. This possibility can weaken the conclusion.

So B fits perfectly.

What does the percentage of bicyclists from all the bicyclists have to do with bicycling on the left being made illegal ?

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