Take the quiz test your understanding of the key concepts covered in the chapter. Try testing yourself before you read the chapter to see where your strengths and weaknesses are, then test yourself again once you’ve read the chapter to see how well you’ve understood.

1. What exactly is an interaction/moderation effect?

When a third variable (X_{1}) and an independent variable (X_{2}) affect the dependent variable (Y) simultaneously

When a third variable (X_{1}) reduces the effect of an independent variable (X_{2}) on the dependent variable (Y)

When a third variable (X_{1}) affects the relation between an independent variable (X_{2}) and the dependent variable (Y)

When a third variable (X_{1}) affects an independent variable (X_{2}) but not the dependent variable (Y)

Answer:

c. When a third variable (X1) affects the relation between an independent variable (X2) and the dependent variable (Y)

2. What is a product-term the result of?

Multiplying two variables

Taking the ratio of two variables

Subtracting one variable from another

Adding two variables

Answer:

a. Multiplying two variables

3. What is a simple main (conditional) effect?

The effect of X_{2} on X_{1} when Y is equal to 0

The effect of X_{1} on X_{2} when Y is equal to 0

The effect of X_{2} on Y when X_{1} is equal to 0

The effect of X1 on Y when X2 is equal to 0

Answer:

c. The effect of X2 on Y when X1 is equal to 0

d. The effect of X1 on Y when X2 is equal to 0

4. When we estimate an interaction model with the mean-centred variables (X1 and X2) what will the coefficients on these predictors reflect?

The slope on X1 for those having the mean score on X2

The slope on X2 for those having the mean score on X1

The slope on X2 and X1 for those having the mean score on Y

None of the above

Answer:

a. The slope on X1 for those having the mean score on X2

b. The slope on X2 for those having the mean score on X1

5. Which of the following commands in Stata can we use to compute the simple main effects after the estimation of an interactive regression model?