A Professor Provides a Special Study Guide to the Students

Multiple Choice

A professor provides a special study guide to the students who chose seats in the front two rows of class.Later these students get better than average test scores.What is wrong with this experiment?​

A) The professor failed to provide demand characteristics.
B) ​The procedure probably had too many independent variables.
C) ​Students were not randomly assigned to groups.
D) ​The experiment did not have a hypothesis.