【简答题】A. 10 percent to 25 percent for the proportion of workers who use drugs occasionally on the job B. determine exactly when drug use becomes abuse C. the 1920s until the 1960s D. the 1960s until ...
【单选题】In a sample of patients at an animal hospital, 30 percent are cats and 60 percent are not dogs. What fraction of those patients who are not cats are dogs?