Lecture 10

Question 1

Describe strategy #1: Simple effects

Answer 1

• Do if have no planned compaisons regarding the interaction and have a significant AxB interaction.
• Refers to a systematic analysis of treatment means either: one row at a time OR one column at a time
  i. e. examine the effects of 1 IV (factor) with the other IV held constant.

Question 2

What do we do if the simple effect is significant and has more than one degree of freedom?

Answer 2

Follow it up with a simple comparison (akin to a single-df comparison)

Question 3

After doing the simple effects and finding significance, do we completely understand the interaction? why or why not?

Answer 3

No.
We have one significant simple effect but it has more than one degree of freedom so we still don’t know exactly where the significant difference lies.
- Need to do simple comparisons for our significant simple effect.

Question 4

Describe strategy #2: Interaction contrasts

Answer 4

• Used to test planned interaction comparisons (both simple & complex)
• Transform the factorial design into one or more 2x2 factorial designs
• Test whether the 2x2 interaction is significant
• if it is significant, then follow up with an analysis of simple effects, if it is not significant –> can do post hoc comparisons with Tukey.