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Old 03-08-2013
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Question Challenging Statistics Q?

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-year 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
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Old 03-08-2013
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Quote:
Originally Posted by Evergreen View Post
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-year 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
I will go for C
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Old 03-09-2013
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i think its e
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Old 03-09-2013
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B.

correct me if im wrong.

they are asking how many people died because of alcohol related motor accidents.
so isnt that 75% of 400 = 300 ?

Last edited by samren17; 03-09-2013 at 07:23 AM. Reason: mistyping answer.
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Old 03-09-2013
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okay i misread it.how do we do a 1 yr incidence.is it divide by 2.so
A - 150 ?
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Old 03-09-2013
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I think its A.

The question is asking for the 1-year incidence of alcohol-related motor vehicle fatalities ONLY. The information on the first sentence of the question stem seems irrelevant for what they are asking.

The incidence of alcohol-related fatalities is 300/600,000 in TWO YEARS. If you want to get the incidence of just ONE year, yes you can divide by 2, but then the concept changes a bit, because now that would be 150 new cases per 600,000 person-years. (This assumes that the incidence rate remains constant per year)

I am not 100% sure of this, but I think A this is the right answer.
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Old 03-09-2013
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Quote:
Originally Posted by rafdelag View Post
I think its A.

The question is asking for the 1-year incidence of alcohol-related motor vehicle fatalities ONLY. The information on the first sentence of the question stem seems irrelevant for what they are asking.

The incidence of alcohol-related fatalities is 300/600,000 in TWO YEARS. If you want to get the incidence of just ONE year, yes you can divide by 2, but then the concept changes a bit, because now that would be 150 new cases per 600,000 person-years. (This assumes that the incidence rate remains constant per year)

I am not 100% sure of this, but I think A this is the right answer.
The incidence of alcohol-related fatalities is 300/600,000 in TWO YEARS. can we divide it to two for ONE year? I'm a bit confused.
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Old 03-09-2013
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Quote:
Originally Posted by Evergreen View Post
The incidence of alcohol-related fatalities is 300/600,000 in TWO YEARS. can we divide it to two for ONE year? I'm a bit confused.
Yes I believe you can. That is what I explained on my previous post.

The thing is that when you divide, you now call that person-years, but its just formality.

(Instead of 150 cases per 600,000 persons per year, you call that 150 cases per 600,000 persons-year.
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