To Test the Effects of Eating on Learning, Professor Lee

Multiple Choice

To test the effects of eating on learning, Professor Lee permits her morning class to bring snacks to class but forbids her afternoon class from bringing snacks. To measure performance, she counts the number of "intelligent questions" asked by students in each class, and reports getting more such questions in the morning class. What are two serious flaws in this experiment?

A) too many dependent variables and lack of an independent variable
B) lack of blind observations and lack of a dependent variable
C) lack of random assignment and lack of blind observations
D) demand characteristics and presence of too many independent variables