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20 Sep 2008, 10:56
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N
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What is the accurate rate for a certain disease testing?
1). 96% of the positive results are true, and 90% of the negative results are true.
2). 8% of all people for the testing actually suffered the disease
???
1). 96% of the positive results are true, and 90% of the negative results are true.
2). 8% of all people for the testing actually suffered the disease
???
Archived Topic
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This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
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20 Sep 2008, 11:05
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vivektripathi
C IMO.
From both stem,
8% of all people actually suffered...positive result and true OR negative result but false. So accuracy rate is 96% x 10%.
20 Sep 2008, 13:23
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Richardson
Where did you get the 10% from ( if you are referring to the negative results that were false) why do you think the answer has to be C?
The wording of B is really ambiguous to me. What does it mean by suffered the disease? They came for testing when they were already knew they had the disease. (or) Does it mean 92% of all the people tested do not suffer the disease. In either case I don't see how it relates to the accuracy of the test.
accuracy = ( true positives + true negatives ) / total cases )
A says
(.96P + .90N) / (P+N)
We dont know P +N
B says
0.08 (X) = P
0.92 (X) = N
Insuff we don't know X
Combine A & B to substitute in terms of X to solve for accuracy.
Initially I picked A but C seems to be the answer. Tough one!
