Interactions in GLMs

Question 1

An interaction is:

Answer 1

when the effect of one IV on the DV is different for different values of another IV. This is also known as moderation.
NB tested by creating a cross product of the two IVs and including it in the analysis

Question 2

Interactions with Categorical Variables

Answer 2

GLM taste WITH coffee size
/ PRINT = PARAMETERS
/ DESIGN = coffee size coffee*size

• PRINT = PARAMETERS outputs a list of parameter estimates

Question 3

Interactions with Numeric Variables

Answer 3

GLM taste WITH coffee_strength size
/ PRINT = PARAMETERS
/ DESIGN = coffee_strength size coffee_strength*size.