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Old 04-16-2012
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Stats Truly Diseased versus Truly Positive!

I don't know if that is my weakness only but

In U world questions for biostatistics, some times it mention patient who are truly diseased ......(and it means the true positive )
and other times the question mentions also Patients who are truly diseased and it means (total patient having the disease)
so how to differentiate between it?
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Old 04-16-2012
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I think it would help all of us if you gave us a few specific examples.
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Old 04-16-2012
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Truly diseased does not necessarily have to be true positive. It can be shown as false negative by not very accurate test.

So does truly healthy - can still be shown as false positive.
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Old 04-16-2012
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truly diseased means total people who have the disease (true positives + false negatives).
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Old 04-16-2012
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Truly diseased- total no. Ppl having disease

True positive- no. Of people having disease who were found out by the said testing method. So truely positive> true positive coz I don't think there is any test which is 100% sensitive.

Ppl Correct me if I'm wrong
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Old 04-16-2012
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Quote:
Originally Posted by Rookie View Post
Truly diseased- total no. Ppl having disease

True positive- no. Of people having disease who were found out by the said testing method. So truely positive> true positive coz I don't think there is any test which is 100% sensitive.

Ppl Correct me if I'm wrong
i dont think in a question they will ever have the terms 'true positive' and 'truly positive' together.

true positives = TP
total positives/total diseased = TP + FN.

those are the only two terms you will see.
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Old 04-16-2012
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Quote:
Originally Posted by Dr.NickRiviera View Post
i dont think in a question they will ever have the terms 'true positive' and 'truly positive' together.

true positives = TP
total positives/total diseased = TP + FN.

those are the only two terms you will see.
Pardon , it should have been Truly Diseased ..
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Old 04-17-2012
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Quote:
Originally Posted by Rookie View Post
Pardon , it should have been Truly Diseased ..
Lol. Rookie mistake.
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Quote:
Originally Posted by Valkoff View Post
Lol. Rookie mistake.
He he he...
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Old 04-17-2012
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LOLS. Its pretty easy. Disease people are the total no. of people with the disease. True positives are the no. of people who have the disease and their screening/diagnostic test results also came back positive.

Lets apply this in the formula of sensitivity:

TP/TP+FN = TP/No. of disease individuals= 1- FN rate
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