1. a. Give three different examples of concrete populations and three different examples of hypothetical populations.

b. For one each of your concrete and your hypothetical populations, give an example of a probability question and an example of an inferential statis- tics question.

2. Many universities and colleges have instituted sup- plemental instruction (SI) programs, in which a stu- dent facilitator meets regularly with a small group of students enrolled in the course to promote discussion of course material and enhance subject mastery. Sup- pose that students in a large statistics course (what else?) are randomly divided into a control group that will not participate in SI and a treatment group that will participate. At the end of the term, each student s total score in the course is determined.

a. Are the scores from the SI group a sample from an existing population? If so, what is it? If not, what is the relevant conceptual population?

b. What do you think is the advantage of randomly dividing the students into the two groups rather than letting each student choose which group to join?

c. Why didn t the investigators put all students in the treatment group? Note: The article Supplemen- tal Instruction: An Effective Component of Stu- dent Affairs Programming (J. College Student Dev, 1997: 577-586) discusses the analysis of data from several SI programs.