Epidemiology & Prevention USMLE Step 1 Practice Question
A screening program for colorectal cancer detects 95% of cases in people with the disease and correctly identifies 90% of people without the disease as disease-free. In the general population, the prevalence of colorectal cancer is 1%. A positive test is obtained in a 60-year-old man. Which of the following best estimates his probability of actually having colorectal cancer?
Answer choices
- AApproximately 9%Correct answer
- BApproximately 95%
- CApproximately 99%
- DApproximately 50%
- EApproximately 85%
- FApproximately 1%
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