In the figure below, what is the main clue to the fact that there may be a statistical interaction between the two independent variables (size and symmetry)?
A)The fact that one line is higher than the other.
B)The fact that both values are lower on the left than on the right.
C)The fact that the lines are not parallel.
D)The fact that mean reaction time is always between 120 and 200 ms.
E)The fact that the researcher has displayed the data using a line graph.

Question

In the figure below, what is the main clue to the fact that there may be a statistical interaction between the two independent variables (size and symmetry)? 
A)The fact that one line is higher than the other. 
B)The fact that both values are lower on the left than on the right. 
C)The fact that the lines are not parallel. 
D)The fact that mean reaction time is always between 120 and 200 ms. 
E)The fact that the researcher has displayed the data using a line graph.

Quizplus · Accepted Answer

The fact that the lines are not parallel suggests that there is a statistical interaction between the two independent variables. This means that the effect of one independent variable on the dependent variable depends on the level of the other independent variable. In this case, the effect of size on reaction time depends on the level of symmetry, and vice versa.

In the Figure Below, What Is the Main Clue to the Fact