Roles of Variables

A covariate is included in a model to:

• Explain the X→Y mechanism
• Account for external variance in the outcome
• Distort the X→Y relationship
• Change the X→Y relationship strength

A study on job autonomy and job satisfaction controls for income. What is income’s role?

• Moderator
• Mediator
• Covariate
• Confounder

What is the primary role of a predictor variable in a statistical model?

• To explain variance in the outcome variable
• To distort the relationship between two other variables
• To change the strength of the relationship between two variables
• To account for external influences on the outcome

A study examines whether mindfulness training reduces anxiety. What is the role of mindfulness training?

• Mediator
• Predictor (independent variable)
• Moderator
• Confounder

A study shows that exercise reduces stress more for women than men. What is gender’s role?

• Moderator
• Mediator
• Confounder
• Predictor

A mediator variable:

• Directly affects the outcome variable
• Explains how or why the predictor affects the outcome
• Changes the strength of the X→Y relationship
• Is unrelated to the predictor

A study finds that student class engagement improves course final grades because class engagement improves comprehension. What is comprehension’s role?

• Confounder
• Moderator
• Mediator
• Covariate

The outcome variable in a study represents:

• The variable being manipulated by the researcher
• The effect or result being measured
• A variable that explains the mechanism between X and Y
• A variable that changes the X→Y relationship

A moderator variable:

• Explains the mechanism between X and Y
• Is a nuisance variable to control for
• Changes the strength/direction of the X→Y relationship
• Must be associated with both X and Y

A confounder must be associated with:

• Only the predictor
• Only the outcome
• Both the predictor and the outcome
• Neither the predictor nor the outcome