“ Doctors Praise Device That Aids Ailing Hearts” (Associated Press, November 9, 2004) is the headline of an article describing a study of the effectiveness of a fabric device that acts like a support stocking for a weak or damaged heart. People who consented to treatment were assigned at random to either a standard treatment consisting of drugs or the experimental treatment that consisted of drugs plus surgery to install the stocking. After two years, 38% of the 57 patients receiving the stocking had improved, and 27% of the 50 patients receiving the standard treatment had improved. The researchers used these data to determine if there was evidence to support the claim that the proportion of patients who improve is higher for the experimental treatment than for the standard treatment.