Question

A serological test is being devised to detect a hypothetical chronic disease. 500 individuals were referred to a laboratory for testing. 300 diseased persons were among the 500. A serological test yielded 250 positives, of which 90% were true positives. Calculate the predictive value positive of the test.

Answer 1

Answer: the predictive value positive of the test is 0.7

Explanation:

Given that;

Predicted

Diesease No-Diesease Tt

Actual Diesease 225 75 300

No-Diesease 25 175 200

250 250 500

so finding the predictive value positive of the test,

predictive negative value = (175 / (75+175) )

= 175 / 250

= 0.7

Therefore the predictive value positive of the test is 0.7