A study investigated whether taking a test in the same room in which a person studies helps performance on the test.The means are below.Which of the graphs correctly portrays the interaction?
A)Graph A
B)Graph B
C)Graph C
D)Graph D

Question

A study investigated whether taking a test in the same room in which a person studies helps performance on the test.The means are below.Which of the graphs correctly portrays the interaction?  
A)Graph A 
B)Graph B 
C)Graph C 
D)Graph D

Quizplus · Accepted Answer

Graph B correctly shows an interaction between the two variables - the lines are not parallel and there is a crossing point. This indicates that the effect of the room on performance depends on the level of studying, with performance being better when studying and testing are done in the same room but only for those who studied more. Graph A shows a main effect of studying but no interaction, and Graphs C and D show parallel lines which indicate no interaction.

A Study Investigated Whether Taking a Test in the Same