海德沙龙

据说只有18%的人答对： If a test [to detect a disease whose prevalence is 1/1000] has a false positive rate of 5%, what is the chance that a person found to have a positive result actually has the disease, assuming you know nothing about the person's symptoms or signs? 注：1）方括号是我加的，避免断句错误，2）false positive=假阳性。