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Old 06-06-2012
belindalimm belindalimm is offline
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I got A.
First calculate sensitivity and specificity, in this case is 25% and 90%, respectively.

For the case with 10,000 ppl in which 80 ppl definitely have cancer, just apply the sensitivity, 80*25%=20(true positive), and the remaining 99920 ppl are definitely without cancer, and here just apply specificity, 99920*90%=89928, substract 99920 by 89928 and then get the false positive 9992.
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