Compute the odds ratio of progression to hypertension among

Compute the odds ratio of progression to hypertension among patients receiving the new drug as compared to the placebo. The following table shows the results of a screening test hypothesized to identify persons at risk for a rare blood disease a) Compute the sensitivity of the test b) Compute the specificity of the test c) Compute the false positive fraction d) Compute the false negative fraction What type of variable are each of the following? (Dichotomous, Ordinal, Nominal/Continuous)

Solution

No Disease

Disease

Screen Negetive

1274(True negative)

28(False negative)

Screen Positive

51(False positive)

45(True positive)

7. a) Sensitivity – [True positivity/(True positivity + False negativity)] = 45/(45+28) = 45/73 = 0.62

b) Specificity – [True negativity/(True negativity + False Positivity)] = 1274/(1274+51) =1274/1325 = 0.96

c) False positive fraction – False positive/(False positive + True positive) = 51/96 = 0.53

d) False negative fraction – False negative/(False negative+ True negative) = 28/1325 = 0.02

8. A) Height in feet - continuous variable

	No Disease	Disease
Screen Negetive	1274(True negative)	28(False negative)
Screen Positive	51(False positive)	45(True positive)