Research Article

Estimating Prevalence Using an Imperfect Test

Figure 2

Posterior distributions of prevalence for a sample of 100 individuals of whom 20 tested positive, using a test with (a) known sensitivity and specificity each equal to 0.9 (solid line); (b) unknown sensitivity and specificity with prior expectations each equal to 0.9 (dashed line, see text for details of prior specification).
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