A new screening test for West Nile Virus is developed for use in the general population. The sensitivity and specificity of the new test are 60% and 70%, respectively. 300 subjects are screened at a clinic during the first year the new test is implemented. (Assume the true prevalence of West Nile Virus among clinic attendees is 10%.), The predictive value of a positive test is:

The predictive value of a positive test is is 0.43.

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This question is solved using the concepts of sensitivity and specificity.

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The predictive value of a positive test is:

Probability of a positive test, which is 40% of 90% plus 70% of 10%, so:

The predictive value of a positive test is is 0.43.

A similar question is given at

i don't even know man. edge inuity be messing with us. i had to ask a question too.