The specicity of the RTPCR is believed to be almost 100% but some \"user\" errors could take place in its use so we will call it 99%. On the other hand, some estimates of the sensitivity were as low as 70%. 9. Compute and compare the PPV and NPV when the test is used only in patients presenting with a) pneumonia among whom we will estimate a 5% point prevalence at the height of the pandemic in NYC and among b) the general population where we will assume a prevalence was 0.1%.. Use the specificity and sensitivity given above in populations of 10,000. (Bpts) Results of RTPCR Actual Infection Status 5% prevalence Negative Total Results of RTPCR Actual Infection Status 0.1% prevalence Total Positive Negative 10. Describe the impact of prevalence on the NPV and the PPV. {2pm}