A test has sensitivity 90 percent and specificity 85 percent. What is its positive likelihood ratio?
Answer and explanation
Correct answer: B. 6
- Step 1: LR+ equals sensitivity divided by (1 minus specificity).
- Step 2: 0.90 divided by 0.15 is 6.
Answer
6.
Why not the others: 0.67: 0.67 is not a likelihood ratio and inverts the terms. 0.9: 0.9 is the sensitivity alone. 9: Using the false negative rate (0.10) gives 9, which is the wrong formula.
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