Figure: a Researcher Examined Whether Interrogators Who Expect a Suspect to to Be

Figure:
A researcher examined whether interrogators who expect a suspect to be guilty,rather than innocent,use more persuasive interrogation techniques.The researcher created a laboratory situation in which students (the "suspects") were randomly assigned to actually commit a crime or not commit a crime by following a set of instructions given to them.Student interrogators then interviewed a suspect;they were randomly assigned to conditions that led them to believe the suspect was guilty or innocent of the crime.Observers rated the effort used by interrogators to obtain a confession using a 1-10 rating scale (higher scores indicate greater effort) .
Suppose the researcher observed the following means for each group:
-Ratings of effort used to obtain a confession are a

A) repeated measures variable.
B) natural groups independent variable.
C) random groups independent variable.
D) dependent variable.