Confidence Interval -- Likelihood Ratio

Instructions: Enter parameters in the Red cells. Answer will appear in the blue cells.

This uses the general definition for the likelihood ratio of test result R, LR(R), as the probability of the test result in disease, P(R|D+), divided by the probability of the test result in non-disease, P(R|D-).


Confidence Level (e.g., 0.95)
D+D-
Total number
Number with result R
P(R|D+) or P(R|D-)0.7500.250



LR(R)Confidence Interval
3.0003.000 -- 3.000


Z 0.00
ln(LR) 1.099
Variance of ln(LR) 0.033
SD of ln(LR) 0.183
ln(Lower Bound of CI) 1.099
ln(Upper Bound of CI) 1.099
Lower Bound of CI 3.000
Upper Bound of CI 3.000

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Software utilities by Michael Kohn (makohn@mkanders.com) and Mike Jarrett (mike.jarrett@quesgen.com)

Disclaimer: Software is provided on an as-is basis and no warranty is made of any kind. Calculations are believed accurate but should be verified by the user