In Teaching of Psychology (Aug. 1998), a study investigated whether final exam performance is affected by whether or not students take a practice test. Students in an introductory psychology class at Pennsylvania State University were initially divided into three groups based on their class standing: Low, Medium, and High. Within each group, the students were randomly assigned to either attend a review session or take a practice test prior to the final exam. Thus, six groups were formed: (Low, Review), (Low, Practice exam), (Medium, Review), (Medium, Practice exam), (High, Review), and (High, Practice exam). One goal of the study was to compare the mean final exam scores of the six groups of students.
a. What is the experimental unit of this study?
b. Is the study a designed experiment? Why?
c. What are the factors in the study?
d. Give the levels of each factor.
e. How many treatments are in the study? Identify them.
f. What is the response variable?