When a line graph is used to depict the results of a complex design,an interaction effect is indicated by
A) nonparallel lines.
B) parallel lines.
C) lines that change direction only once.
D) lines that change direction more than once.

Question

Quizplus · Accepted Answer

Nonparallel lines indicate an interaction effect between the two factors being tested. This means that the effect of one factor on the outcome depends on the level of the other factor. If the lines were parallel, there would not be an interaction effect. The other choices (C and D) refer to changes in direction, which could indicate different patterns of results, but do not necessarily reflect an interaction effect.

When a Line Graph Is Used to Depict the Results