The False Positive Paradox: Working Example

Number of people tested
Incidence rate (%)
Test accuracy (%)

From the population of 1000 and the incidence rate of 0.1%, we know that around 1 people will actually have the condition. But as the test is only 95% accurate, of the 1000 tests done 950 will have been correct and 50 wrong.

Only 1.96% of 'positive' results are actually correct.