The Quant 758 / 75
MediumProbability
Bayes — Disease Test
Goldman SachsTwo Sigma
A disease affects 1% of a population. A test is 99% sensitive (true-positive) and has a 1% false-positive rate. Given a positive test, what is the probability the person actually has the disease?
Approach
Compare true positives to total positives.
The 1% prevalence matters enormously.
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