Concept explainers
Exercises 11–15 refer to diagnostic tests. A false negative in a diagnostic test is a test result that is negative even though the patient has the condition. A false positive, on the other hand, is a test result that is positive although the patient does not have the condition.
Steroid Testing It is estimated that 10% of Olympic athletes use steroids. The test currently being used to detect steroids is said to be 93% effective in correctly detecting steroids in users. It yields false positives in only 2% of the tests. A country’s best weightlifter tests positive. What is the probability that he actually takes steroids?
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