=+17. Measles. Health researchers at a large HMO base their cost predictions for measles on the belief that 98% of children have been vaccinated against measles. A random survey of medical records at many schools across the country found that, among more than 13,000 children, only 97.4%

had been vaccinated. A statistician would reject the 98%

hypothesis with a P-value of P 6 0.0001.