Professor Prieto Teaches Two Sections of a Diversity Class

Multiple Choice

Professor Prieto teaches two sections of a diversity class. In the 10:00 class, he focuses on discussion; in the 3:00 class, he mainly lectures. At the end of the semester, he finds the students in the 3:00 class score higher on a measure of multicultural competence. Which of the following threats to validity could be operating in this study?

A) a history effect
B) a selection bias
C) mortality
D) a volunteer bias