Question

A new screening test for lyme disease is developed for use in the general population. the sensitivity and specificity of the new test are 60% and 70%, respectively. three hundred people are screened at a clinic during the first year the new test is implemented. assume the true prevalence of lyme disease among clinic attendees is 10%. the predictive value of a positive test is: 33.0% 18.2% 94.0% 22.2% 6.0%

Answer 1

Answer:

The positive predictive value is 18.2%

Step-by-step explanation:

Let TP (true positive) denote the Sensitivity, and TN (true negative) denote the Specificity, and P prevalence. The Positive Predictive Value is calculated as follows:

$PPV = \frac{TP\cdot P}{TP\cdot P + (1-TN)\cdot(1-P)}=\frac{0.60\cdot0.10}{0.60\cdot0.10+0.30\cdot0.90}=0.182$

The positive predictive value is 18.2%