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 Post subject: CR II page#21 Q.7
PostPosted: Sun Aug 15, 2010 5:11 am 
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Posts: 5
I chose B for this one....please help me understand the logic used in this question...

Regards,
sgmat


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 Post subject: Re: CR II page#21 Q.7
PostPosted: Sun Aug 15, 2010 8:48 am 
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Sometimes on these questions, it's helpful to look at extreme cases in order to see where the numbers might reflect different information.

The question stem tells us that it is more dangerous to ride in an automobile than on a motorcycle.
Then they tell us that 1 person in 19,000 will die in a car, while 1 in 73000 will die on a motorcycle.

If we have only 19000 in our population, then we will have 1 person die in an automobile accident. What if we only have 2 people riding in cars? Then our rate is 50%. On the other hand, if all of the 19000 people in our population ride in cars, then 1 in 19000 passengers will die. (Note that 1 in 19000 passengers is a different statistic than 1 person in 19000 among the general population.)
Now, look at the motorcycle statistic in a similar fashion. If 1 person in 73000 will die in motorcycle accidents, but we only have 1 motorcycle rider in our population of 73000, then we have a fatality rate of 100%. If, on the other hand, we have 73000 motorcycle riders, then our statistic is different.

For this reason, we need to know how many of a given set of automobile passengers are killed as well as how many of the motorcycle riders are killed, instead of using numbers as a percentage of the population at large.

Hope this helps some, but let me know if you want further elaboration!

Veritas Help


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 Post subject: Re: CR II page#21 Q.7
PostPosted: Sun Aug 15, 2010 9:56 am 
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Joined: Wed Aug 11, 2010 10:02 am
Posts: 5
[quote="VP_Help"]Sometimes on these questions, it's helpful to look at extreme cases in order to see where the numbers might reflect different information.

The question stem tells us that it is more dangerous to ride in an automobile than on a motorcycle.
Then they tell us that 1 person in 19,000 will die in a car, while 1 in 73000 will die on a motorcycle.

If we have only 19000 in our population, then we will have 1 person die in an automobile accident. What if we only have 2 people riding in cars? Then our rate is 50%. On the other hand, if all of the 19000 people in our population ride in cars, then 1 in 19000 passengers will die. (Note that 1 in 19000 passengers is a different statistic than 1 person in 19000 among the general population.)
Now, look at the motorcycle statistic in a similar fashion. If 1 person in 73000 will die in motorcycle accidents, but we only have 1 motorcycle rider in our population of 73000, then we have a fatality rate of 100%. If, on the other hand, we have 73000 motorcycle riders, then our statistic is different.

For this reason, we need to know how many of a given set of automobile passengers are killed as well as how many of the motorcycle riders are killed, instead of using numbers as a percentage of the population at large.

Hope this helps some, but let me know if you want further elaboration!

Veritas Help[/quote]
Thankyou. I got this one now.

Regards,
sgmat


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