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燦榮 | 22nd Jul 2011 | 心理 | (27 Reads)
  • The probability that a woman has breast cancer (prevalence) is 1 percent.
  • If a woman has breast cancer, the probability that she tests positive (sensitivity) is 90 percent.
  • If a woman does not have breast cancer, the probability that she nonetheless tests positive (false-positive rate) is 9 percent.

What is the best answer to the patient's query?

A. The probability that she has breast cancer is about 81 percent.

B. Out of 10 women with a positive mammogram, about nine have breast cancer.

C. Out of 10 women with a positive mammogram, about one has breast cancer.

D. The probability that she has breast cancer is about 1 percent.