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Hello,
What equation would I use to solve the following:
If 40% of the population is unfit, and
35% of the population has heart disease, and
25% of heart disease is due to being unfit,
what is the percent of the population that is both unfit and has heart disease?
Please include the equation you use to get your answer.
Thanks.
P(unfit) + P(heart disease) - P(unfit and heart disease)
40% + 35% - 25% = 50%
Last edited by bobbym (2009-05-13 09:04:59)
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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Thanks, bubt I don't think that's right. If you use that logic to calculate the percent for all four possible groups, you'll get more than 100%. The 4 groups are:
unfit w/HD
unfit w/o HD
fit w/HD
fit w/o HD
Thanks, but I don't think that's right. If you use that logic to calculate the percent for all four possible groups, you'll get more than 100%. The 4 groups are:
unfit w/HD
unfit w/o HD
fit w/HD
fit w/o HD
Hi ssmath;
You can't just add them all up because you will be counting some twice or more. A Venn diagram shows this clearly.
Last edited by bobbym (2009-05-13 09:30:35)
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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Okay, I see that, but can you get specific percents for each group?
The appropriate Venn Diagram would be a square divided into 4 quarters by a horizontal line intersecting a vertical line. The two top quarters are, say, heart disease patients; the two bottom quarters are non-patients. The two left quarters are fit people; the two right quarters are unfit people.
But what are the relative percents of the 4 quarters?
No, I don't think that is the correct diagram.
We can calculate everything from what we already know.
unfit with heart disease 25% Given
unfit without heart disease 15% 40% - 25%
fit with heart disease 10% 35% -25%
fit without heart disease 50% The rest
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
That's not right either. 25% of heart disease is DUE TO being unfit; not the same as 25% unfit w/heart disease.
True, but you are asking another question. I am answering post #3 which says with and without
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
I got the following using a 1 x 1 square Venn diagram. A vertical line at .65 divides heart disease (HD) patients from non-patients; HD patients are the two squares on the right, taking up 35%. A horizontal line at .6 divides fit people from unfit ones; fit people are the two top squares, taking up 60%.
From that, I get the following numbers (by multiplying the dimensions of each quarter, like finding the area of a square):
fit HD: 60% x 35% = 21%
unfit HD: 40% x 35% = 14%
fit, no HD: 60% x 65% = 39%
unfit, no HD: 40% x 65% = 26%
That adds up to 100%. The only problem is that the percent of HD due to being unfit doesn't equal 25%. Assuming a population of 100:
14 unfit w/HD divided by 35 total with HD = 40% HD due to unfitness.
The reason the 25% isn't represented is that it's not used in any of the four equations. Does anyone know how to integrate it? Or is it possible that the original word problem is logically impossible?
I solved this -- thanks for everyone's help.
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