11-02-2009, 06:27 AM
The blood supply used by a local hospital for transfusions during surgical procedures is discovered to be infected with hepatitis C. To protect the blood supply from future contamination, all new donors are required to be screened for hepatitis C. The test used for this screening has a sensitivity of 95%, and a specificity of 90%.
If this test is used on a sample of donors in which 10% are known to have hepatitis C, what is the chance that a donor who tests negative is actually free from the disease?
A. About 99%
B. About 95%
C. About 90%
D. About 85%
E. About 50%
F. About 45%
If this test is used on a sample of donors in which 10% are known to have hepatitis C, what is the chance that a donor who tests negative is actually free from the disease?
A. About 99%
B. About 95%
C. About 90%
D. About 85%
E. About 50%
F. About 45%