NBME Form 1 - Incidence

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NBME Form 1 - Incidence

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humpf!!
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05/15/06 - 11:29 AM

Eight hundred motor vehicle collisions occurred over 2 years in a city with a population of 600,000; 600 of these accidents were alcohol-related. During the same period, there were 400 fatalities due to motor vehicle collisions, of which 75% were alcohol-related. Which of the following best represents the 1-vear incidence of alcohol-related motor vehicle fatalities in this community?

A) 150 per 600,000

B) 300 per 600,000

C) 450 per 600,000

D) 600 per 600,000

E) Unable to determine from available information

kingsofke
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05/15/06 - 02:11 PM

A) 150 / 600,000

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humpf!!
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05/15/06 - 04:05 PM

kingsofke - if you could explain your answer, that would be great. i was confused bc the question asked about a 1-yr incidence, whereas the info spans 2 years (so i thought the answer was E).

but if it is A, how did you get that?

kingsofke
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05/16/06 - 06:22 AM

The first bit of info is useless. What we are concerned with is fatalities. Which as the second line says are 400 in 2 years, 75% were alcohol related. which make it 300 fatalities alcohol related. If 300 in 2 years then 150 in each year. So the answer.

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nadiabarati

06/05/06 - 09:21 AM

Can we really say if 300 in 2 years so 150 in a year. What if we had 200 in a year and then 100 in the next year. It's not rational I think.

The answer is E.

eaguin
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07/22/06 - 04:15 PM

I think is A

pallav
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07/25/06 - 10:37 PM

comes to 150/600000 but can anybody give a lucid explanation

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alpha12
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07/28/06 - 08:31 PM

the explanation was given already: 75% of 400 over 2 years is 300; thus for 1 year, it's 300:2=150

the incidence will be 150/population=150/600,000

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Ivil
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07/28/06 - 09:05 PM

i go with nadiabarathi. we cant predict incidence from the data given.

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young_doc
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08/01/06 - 01:54 PM

#10

this has been discussed...(and yes we CAN predict indicidence from the given data smiling face

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mjl1717
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08/01/06 - 03:39 PM

#11

its either e or a// someone has to ask an epidemiologist "can you divide 2 years by 2 in order to to get incidence for 1 year!! [this is an ongoing saga or a futile cycle]

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young_doc
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08/01/06 - 03:47 PM

#12

I'm pretty sure we can make that assumption. That's what Stats is all about! It's all about odds and probabilities. So if something happens 10 times every 2 years, it is safe to assume (statistically speaking) that it will happen 5 times ever 1 year.

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mjl1717
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08/01/06 - 03:59 PM

#13

young_doc wrote:
I'm pretty sure we can make that assumption. That's what Stats is all about! It's all about odds and probabilities. So if something happens 10 times every 2 years, it is safe to assume (statistically speaking) that it will happen 5 times ever 1 year.

Guys I think this is good deductive reasoning!

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