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Moderator. A third variable that effects the direction or strength of the relationship between 2 other variablesModerators can be continuous or categorical variables. Moderator. A moderator is represented by an interactionWhen a relationship between two variables holds only at certain levels of th
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1. Mediator vs. Moderator Relationships
2. Moderator A third variable that effects the direction or strength of the relationship between 2 other variables
Moderators can be continuous or categorical variables
3. Moderator A moderator is represented by an interaction
When a relationship between two variables holds only at certain levels of the third variable (moderator)
4. Moderator Examples of Moderator Variables
Sex (certain relationships hold in one sex but not the other) - sex moderates the relationship between analgesics and pain report
SES - level of SES moderates the relationship between compliance and treatment outcome
5. Moderator Statistical Approaches
ANOVA interaction effects
Regression product vectors (interaction)
Categorize moderator variable and test for differences in regression coefficients at each level
6. Moderator
7. Mediator A third variable “intervenes” between a predictor and predicted variable
The mediator variable may explain “why” two variables are related
Stimulus - Organism - Response
the Organism mediates the relationship between a stimulus and behavior
8. Mediator
9. Mediator Conditions for Mediation
1. Depression predicts pain
2. depression predicts catastrophizing
3. when depression/cat relationship and cat/pain relationship controlled, Depression/pain relationship is reduced or eliminated
10. Mediator Statistical Approach
Regression
could run three separate regressions
hierarchical regression
LISREL
11. Mediator