Moderation, Logistic Regression, Mixed ANOVA Flashcards
What kind of relationship do we look for in a moderator
Is the relationship between predictor (X) and outcome (Y) affected by the moderator (M).
What are 4 different changes in relationship with a moderator
1.smaller
2.larger
3.disappears
4.direction changes
What is a main difference between mediation and moderation
Mediation shows how a predictor works,
Moderation shows whether or when it works.
shows us under what conditions we can expect a relationship
What is the difference between moderation mediation and a third variable problem
Third variable problem:
3rd variable
The mediator is predicting both the main predictor and the outcome.
What is some language showing you have a moderation
“Only when” “Sometimes” “It depends”
How does a moderator impact the relationship of the predictor to the outcome
Depending on the level of the moderator, the beta will increase or decrease in strength
Which type of variable is easier to visualize in a moderation analysis
categorical moderator (as opposed to continuous)
What extra step do you need to do to calculate a moderation analysis, as opposed to a regular 3-variable mutliple regression
We need to add an interaction. The model we run includes 3 predictors instead of 2, but the third is just the multiplication of X by M
Which elements are part of the moderation model
- Predictor
- Moderator
- Interaction: Predictor x Moderator
- Outcome
What is an important first step to run a moderation analysis
All predictors need to be centered before conducting your regression.
Centering means subtracting the Mean from each observed value.
Conveniently, standardized variables are automatically centered
The interaction term must be calculated using the centered predictors.
How can you tell if you have a significant moderator, and what should you do next
If the interaction term beta is significant, then we have found moderation.
You will get three betas: 2 predictors + Interaction
Follow it up with a simple slopes analysis
What are the simple slopes plot, how should you interpret it
This plot allows us to visualize the effect.
It will give the average estimate, the low (-1SD) and the high (+1SD) estimate as well as p-values. If the p-values are significant, you can determine which level of X is different form the average.
What are main features of logistic regression
- Outcome we’re interested in is categorical.
- Doesn’t require straight lines
- Can use categorical and continuous predictors
What is a binary logistic regression
The outcome has only two possibilities
What is the goal of a logistic regression
Instead of focusing on the amount of variability in the outcome that is explained, we’re trying to predict which category participants fall into
With binary logistic regression we make a model to predict which of the outcome variable’s two categories each participant falls into, and then check that model against the observed outcome.
What are the minimum and maximum value of logistic regression
Probability ranges between 0 and 1.
You can only have zero if the bottom of the equation reaches infinity, which won’t happen. But in theory, it could reach zero.