1. Use a random number generator from a statistical computer package to assign 20 patients to two treatments, with 10 patients receiving each treatment.
2. An investigator wishes to take a sample of 160 undergraduate students from a university to assess the attitudes of undergraduates concerning the student health service. The investigator suspects that the attitudes may be different for freshmen, sophmores, juniors, and seniors since it is thought that the attitudes might change as the students get more experience with the system. The investigator would like to make estimates for each class as well as the total body of undergraduates. Choose a method of sampling and give the reasons for your choice.