Machine A makes of a factory's items and of them are defective. Machine B makes the other and of them are defective. An item is found to be defective. What is the probability it came from machine A?
Answer and explanation
Correct answer: B.
- Step 1: Use Bayes' rule with the total probability of a defect: . Step 2. . **Answer: . Why not the others:** is the prior, is , and ignores both the shares and the defect rates.
Practise more Mathematics A: Functions, Calculus, Complex Numbers and Probability.
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