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# Questions tagged [interaction]

A situation where the effect of an explanatory variable may depend on the value of another explanatory variable.

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18 views

### Multiple linear regression with dependent as a dummy predictor

I have a model $Y = \alpha + \beta_1X_1 + \beta_2X_2$. $Y$ has a bimodal normal(ish) distribution, so I'm looking to see if the relationship between the predictors and the response is different for ...
90 views

### Help in Two-way ANOVA with Significant Interaction

(note: I removed the original table because there were some mistakes in it. I preferred to use R annotation of Sal's answer.) Hi everybody, I got the following results for an experiment of ...
67 views

### Can I use a t-test to follow-up on a non-significant interaction in an ANCOVA?

I have an experiment that compares the impacts on students' learning (as measured by their performance on a pre and posttest) of two versions of a classroom intervention: D and R. I did an ANCOVA ...
16 views

### Logit model: Interpretation of interaction effect with only dummies

I have a large binary logit model (cross-section) with many variables, mostly dummies. From the information on age, I have created 6 dummies: 17-24, 25-34, 35-44, 45-54 (reference group), 55-64 and 65+...
20 views

### How to properly represent a sum of interactions in ANOVA?

I would like to include an ANOVA-style linear model in my work that shows the main effects but has interactions lumped together in one term for brevity. When I do the analysis I will include the ...
9 views

### Interaction in logit

I am estimating a model where interaction terms play a role, and I am wondering which specification I should use, and how to interpret the results. More specifically, I regress a binary variable, say ...
41 views

### Interaction term to deal with heteroscedasticity

The variance in my dependent variable changes with a changing value in an important independent variable and is hence probably distorting the measured effect of the treatment. Can I combat this form ...
15 views

### Interpreting models with omitted interaction effects

Suppose I have two regressors, task availability (Xa) and task participation (Xp), and a DV Y. One can only participate in a task if it is available, but one can choose not to participate even if a ...
99 views

### How to interpret interaction in Log Log models

I have the following model, and I am not sure how to interpret the elasticity of the interaction term (log-log coefficients): Log(member) = 3.61 + 0.52 Log(Poor) - 0.26 Log(Sick) + 0.04 (Log(poor) * ...
26 views

### Modeling interaction in variance

I run an experiment on both men and women participants, where I manipulate an independent variable. I know that the manipulation causes greater variance in the outcomes of the experimental group (a ...
32 views

### Mediation model of time series data

I'm quite new to mediation analysis so hopefully I can clearly explain my problem. I wish to conduct a mediation model with a single mediating variable. The independent variable is a time series EEG ...
130 views

### Interaction between dependent and independent variable

I am conducting a multiple linear regression on data from a cross-sectional study, and I suspect that there is an interaction between my dependent variable (a disease risk marker) and one independent ...
63 views

### Interpretation linear mixed model with interaction

I'm doing linear mixed model with an interaction between the time and my exposure. The fixed effects look like this : Y ~ T + T*GRP + X with T the time, GRP the exposure and X the adjustements ...
22 views

### Testing moderation hypothesis in regression discontinuity analysis

I am doing a regression discontinuity analysis in R (using the rdd package) and I am interested in testing a moderation hypothesis. I think that the effect of the treatment will depend on a third ...
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### What does it mean when running ANCOVA with two moderators and one of the interactions is insignificant when ran together?

I am hypothesizing that there are two moderators in the relationship between IV and DV. I ran one ANCOVA with moderator A and the interaction between IV and moderator A is significant. Then I ran ...
153 views

### Multiple regression: Interpreting three-way interaction with two categorical variables and one numeric (in R)

I have two quick questions. I’d like to confirm that I’m interpreting correctly one of my coefficients from a 3-way interaction in a multiple linear regression model. The summary of my model is below. ...
467 views

### Different ways of modelling interactions between continuous and categorical predictors in GAM

The following question builds on the discussion found on this page. Given a response variable y, a continuous explanatory variable ...
5 views

### interaction term between continuous moderator and independent dummy variable (in OLS)

i would like to check if there is an interaction between the independent contiunous variable leverage and the choice of auditor - dummy variable (audited by big4: 1). The dependent variable is ...
19 views

### Interpretation of model with interaction quotient

I am unsure about the interpretation of $\beta_1$ in the binary choice model $$Y=𝟙[\beta_0+\beta_1V+\beta_2\frac{V}{C}+\varepsilon>0].$$ Because I know that $V$ and $C$ are uncorrelated, I do ...
8 views

### Simple two way interaction in three way repeated measures ANOVA

I am working on balance study, and I ran the way repeated measures ANOVA on SPSS with (A three balance conditions)* (B two vision conditions EO EC)* (C two surface types firm and soft). There are no ...
12 views

### Interaction analysis with categorical predictor and continuous moderator (and continuous outcome)

I'm working on a study in which I collect the following variables (among others), with which I would like to conduct a moderation analysis in R. condition (categorical, 2 levels) - predictor trait ...
32 views

### Can a complex interaction term mean more than what it's composed of?

I'm cross-posting this question on both Economics and Cross Validated to get answers from a different perspective on each field. It is generally accepted to cross-post if the question is tailored to ...
18 views

### Visualise: Interactions with Two Categorical Variables controlled for a continous variable

What is the best way to visualise an interaction between two categorial variables controlled for a third continous variable. e.g. ...
23 views

### Moderated mediation included in a bigger path diagram

I want to specify a path diagram with 7 (observed) variables. It includes the following two relationships: b ~ a; c ~ a+b. Analyzing these three variables separately, it is possible to define a ...
29 views

### Is the significance of an interaction more important that the fit of a model?

I am new to lme4 and I am not sure if I understand correctly. If I want to know if there is an interaction between A and B, I have to write two models and then compare them with anova and the one with ...
15 views

### Conditional sorts as an alternative for regression models

I have the following regression model R=a+bX+cZX where R is the return and X is a control variable and Z is the variable of interest. As an alternative approach to the use OLS, often conditional ...
10 views

### Does an Interaction term **always** require “lesser order” term in the model? [duplicate]

Assuming a simple Linear model: $$\hat y = b_0 + b_1.x_1 + b_2.x_2$$ Where all coefficients are relevant to the model (p-value < $\alpha$). Then adding the interaction term: \hat y = b_0 + b_1....
17 views

### Two models or one? Significant effect of predictor - in two treatments

Say you have a response variable that you suspect is linearly affected by your predictor variable, but only under treatment A and not treatment B. I was tempted to model this as a linear model using ...
192 views

### Can I remove significant interaction variable in regression model?

I have a regression model, which consists of 4 predictors and 1 interaction - i dont know what are the correct symbols and terms, so I will drop my model here: ...
19 views

### How do I address suppression (sign flipping) in a moderated mediation?

I am using the PROCESS macro (model 7) to examine a moderated mediation and ran into a new problem. Bivariate correlations show X is positively correlated with Mediator, but not with Moderator. ...
29 views

### How to measure the amount of confounding in tensor interaction in GAMs?

I am interested in fitting an additive model with tensor interaction terms. This construction is described in Wood (2006) and used in the mgcv ...
56 views

### Three-way interaction: slope difference test if simple slope is insignificant

I am currently conducting a three-way interaction (linear OLS regression) with three continuous variables. My dependent variable is also continuous. The three-way interaction term is significant (yes,...
22 views

### Interpreting the relationship between my instrumented variable (X1), X2, and Y (IV regression)

I have run an IV regression with a dichotomous outcome (Y) and my endogenous ("instrumented") regressor (X1) is also dichotomous. I am assessing whether continuous variable (X2) is moderating the ...
15 views

### Epidemiological research involving age at exposure to events as a continuous predictor

I'm looking for some more sophisticated analytical methods for assessing age-at-exposure effects. The literature I'm reading typically polytomizes age into groups, which I'd like to use as a last ...
80 views

### interpreting interactions in logistic regression in R

I have a logistic regression and one dummy and one continuous variable and their interaction term. What is the right way to obtain marginal effects, i.e. should one use log odds estimates or ...
12 views

### How to transform a continuous variable which is a moderator in ANCOVA into a categorical one?

How do I decide where is the threshold to split it into levels? I ran an ANCOVA with a continuous moderator and it is significant, but I am wondering how to transform it to a categorical variable? Is ...
19 views

### How do you run a moderation analysis and post-hoc in Chi square in spss?

How to test for an interaction in Chi-square? Is it also possible to then test for a further interaction in one of the groups? E.g. I test for an interaction in a whole dataset, then split data (?) ...
87 views

### “Joint” dummy variables for two different variables

I am supposed to show the hazard ratio (HR) stratified by gender (1= female vs. 2= male) and age groups (quartiles, 1-4)*. The combination "female" and "first quartile of age" is supposed to be the ...
7 views

### Testing whether subject-level slopes in two different random slopes models are correlated across-subjects

Sorry for this poor title. Let's say 50 subjects each did 20 trials of an experiment, and I recorded 4 variables from each trial, W, X, Y, Z. For each subject, I want to measure the correlation ...
28 views

### how to interpret if the coefficients of two predictors are positive,the coefficient of the interaction term is negative? [duplicate]

I have a multiple regression model.The predictors A,B,AB are all significant. But the coefficients of A and B are positive while the coefficient of AB is negative. How to interpret it? (A ranges from -...
183 views

### Why is my variable being omitted by stata?

I am carrying out a fixed effect regression. I have a dummy variable called female. The dependent variable docvis refers to hospital visits. I created an interaction term between hhkids and female ...
30 views

### How do I interpret the coefficient of this interaction variable. Should I just be setting my dummy to 1 instead?

I have a dataset which looks at people's number of visits to the doctor. It includes a dummy variable for gender called female and a dummy variable called hhkids which states whether or not someone ...
659 views

### Latent variable interaction: different number of indicators 4 vs 1

I am trying to calculate a latent variable interaction using the unconstrained product indicator approach (Marsh 2004) with double centering (Lin et al. 2010). My data: two latent predictor ...
27 views

### How do I describe an interaction effect with categoric variables?

I have a continuous response variable. It is the conversion rate from an AB test. I noticed that the response variable changes meaningfully based on the experimental group, plus one other variable ...
68 views

### mgcv::gam(). ANOVA decomposition of a factor-by-variable interaction

Suppose: y is a continuous response variable. z is a factor variable, and x is a continuous variable. For example, ...
27 views

### SPSS ANCOVA interaction significant once main effects removed

I'm running a 2x2 factorial ANCOVA, where the factors are either being in condition A or B and either being part of a certain group or not, with two covariates being age and gender. When I run the ...
28 views

### Different main effect in MANOVA and two-way MANOVA? Which one do I use?

I did a MANOVA in SPSS and there is a significant main effect of the IV on only one of my two DVs. Then I did a two way ANOVA to include one more IV, but otherwise use the same variables I've used in ...
34 views

### Interpreting findings of moderation using PROCESS Macro

I have recently conducted a moderation analysis using the PROCESS Macro plug-in for SPSS. I have tested the moderation effect of W (categorical using dummy variables) on the relationship between X (...