Disease test (Bayes)
A disease affects 1% of people. A test has 99% sensitivity (true-positive rate) and 95% specificity (so a 5% false-positive rate). You test positive. What is the probability you actually have the disease? Give a decimal.
Show hints (2)+
- Write out Bayes' theorem.
- The 1% base rate dominates the result.
Answer
Reveal answer →Final answer
0.167 (± 0.01)
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