# Tagged Questions

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

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### How to interpret coefficients of interaction terms in logistic regression in these 2 scenarios?

Let me give a simple example, ...
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### Testing simple slopes in multilevel modeling

I am currently working on a project where my coworker and I are examining the relationship between different aspects of friendship quality and achievement across three time points (grades 3, 5, and 6)....
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### Interaction between 2 quadratic variables

If I have a regression y ~ x1^2 + x1 + x2^2 + x2 + bias, and I want to include interaction between the two quadratic variables, do I make the new regression y ~ x1^2 + x1 + x2^2 + x2 + x1^2*x2^2 + x1^...
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### Significant interaction but simple slopes non-significant [on hold]

I have looked at the boards and have yet to find a clear answer to this question. What does it mean when there is a significant interaction but the simple slopes are non-significant? This question is ...
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### A Question on Interactions in STATA [on hold]

I am trying to replicate one of Wooldridge examples to learn a bit. It is about interacting the dummy variable (black) with a continuous variable (percblck). Here is the code that I have written: <...
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### How to test significant interaction effect

If I have a model, lets say y = a + b1male + b2large + b3medium + b4malelarge + b5malemedium where male is dummy coded 1 for male and 0 for female and large and female are dummies (also 0,1 coded) for ...
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### How to add an interaction term in JAGS?

I'm trying to add an interaction term to a JAGS model. I found this where it shows some interaction terms. But I don't understand what's the guide lines to create an interaction term, which is ...
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### Moderation analysis for repeated measures ANOVA [on hold]

My dataset looks like this: My hypothesis is that the statistical differences between the within-subjects measures (A1 vs A2 vs A3) are moderated by a third variable (mod) which is continuous. What ...
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### Moderated regression: Why do we calculate a *product* term between the predictors?

Moderated regression analyses are often used in social sciences to assess the interaction between two or more predictors/covariates. Typically, with two predictor variables, the following model is ...
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### Regression model for pre-post single group design

I am analysing cross-section data from two time points, i.e. before and after an intervention and I am particularly interested in the causal effect of the intervention. The outcome of interest ($Y$) ...
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### Split v. Interaction Significance

I have a question about splitting the sample versus interacting a variable. My understanding is that if you split the sample and then conduct an analysis you are essentially interacting each ...
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### Interpreting lower order effects not contributing to the interaction terms, when the interaction is significant (C in a regression of A + B + C + A*B)

In a regression including 3 variables, and the interaction of 2 of those variables: Variable A Variable B Variable C Variable A * Variable B, where the interaction of Variable A * Variable B ...
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### Calculate interaction sum of squares by hand

I'm trying to manually calculate the sums of squares (SSs) in a two-way ANOVA in Python. However, I cannot seem to get the correct result for the interaction SS. I'm using the ...
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### How to do contrasts in a significant interaction of 2 variables in a 4 four variable set?

I did an analysis of a 2x2x2x2 mixed factorial anova. The first 3 variables were repeated measures and the last was a between groups analysis. The data in the repeated measures were all reaction ...
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### Interpreting an interaction effect plot and effect sizes range

I have two questions please. One, how can I interpret the following plot where there is an interaction between a categorical variable of four levels (context) and a continuous variable, frequency? ...
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### Can I report simple main effects without an interaction effect?

I have a quick question about reporting simple main effects. I am running a two-way mixed ANOVA and the interaction effect was not significant. I understand that if you have no significant interaction ...
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### Variance-covariance matrix after cluster-robust SEs with clusterSEs package in R

Is it possible to extract the variance-covariance matrix after bootstrapping the standard errors (clusterSEs package)? I want to use cluster-robust standard errors since the number of clusters in my ...
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### Hierarchical regression for testing 2-way & 3-way: include all possible interactions?

I am running a hierarchical regression model. (That is, I am running a series of regression models, adding additional variables each time so that each model is nested within the next. Here, each ...
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### How can we model variable interactions using neural network?

I have 2 independent events as months and tenure and dependent variable 1/0. Does neural network automatically handles interactions, or do we need to tweak it to handle interactions? e.g. I want to ...
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### Interaction term: no R² change

I use hierarchical regression to test whether or not an independent variable moderates the relation between another independent variable and the dependent variable as follows: model 1: control ...
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### Visualizing a two way interaction for a binary dependent variable

I have a dataset that has two continuous independent variables, months and tenure. The target variable is binary, 1/0. I want to visualize how the events change across months*tenure. How can I do that?...
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### About GBM function parameters (Bag.fraction, interaction.depth)

I don't understand how the gbm's parameter "bag.fraction" works. For me, gradient boosting works globally like that : Fit a tree f_hat_b with d splits to the training data (X, r) (where r_i=y_i for ...
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### Negative main effect but positive interaction - GLM in R [duplicate]

I am comparing the density of bird species within towns/cities and the countryside and am interested to see how different habitats affect this. So, I want to see if different habitats (improved ...
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### How to interpret dummy and ratio variable interactions in R

I have performed a regression examining data on crime rates. It looks at a standard ratio type variable (beginning crime rate at a point in time) and a dummy variable (if the countries crime rate is ...
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### how the interaction between one binary variable with several binary variables modeled in logistic?

I want to assess the interaction among genotype (coded as 0 and 1) and dietary intake {(fat intake ‎‎(coded as 0 and 1), carbohydrate intake (coded as 0 and 1 and also energy intake (coded as 0 and 1)}...
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### Binary interactions and significance levels

I am a bit confused by the results from a logistic regression using two-way and three-way interactions (binary variables only). My first regression output was looking at binary predictors of TB and ...
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### How to calculate OR and p-value for allele combination on different chromosomes

I have one question to calculate genetic risk for combination of multiple single nucleotide polymorphisms (SNP). In case-control study dealing with two or more SNPs, is there popular method to ...
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### Interpreting the direction of an interaction effect in Binary Logistic Regression

I have reviewed prior posts in the forum and can't seem to find an answer to a problem I am having with interpreting an interaction: The goal: interpret the direction of the interaction term. ...
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### Over-parameterization in Bayesian Hierarchical Model

Can someone explain the influence of adding parameters to a Bayesian model? I have read from Kruschke that Bayesian analysis 'accounts' for model complexity by way of multiple priors, however I don't ...
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### Method for analyzing interactions of periodical exposures (drug x drug interaction and likelihood of adverse events)

I am interested in studying drug usage interactions (drug x drug) and its relation to adverse events. I would appreciate help with choosing the right model/method for this type of analysis. The data ...
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### Investigating main effect after controlling for guessing

I'm doing a multilevel logistic regression with the dependent variable being word learning scores (Score). There are two independent variables: Condition (Experimental / Control) and WordType (Cognate ...
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### Describing the causal effect of coffe and heat on esophageal tumor. Interaction, confounding, mediation?

The public health world is discussing in these days the news that coffee is no longer considered carcinogenic but heat of the drinks is the real culprit. I'm trying to visualizing this as a causal ...
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### Centering variables for interaction, continuous x catagorical (2 levels)

For a multiple regression analyses I'm looking to assess whether an effect of a contiuous independent variable on a continuous dependent variable is different between two levels of a catagorical ...
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### interaction continuous*dummy: is it possible to treat the continuous variable as the moderator?

This is my first post here so please be kind to me! :-) For my thesis my aim is to run a moderation analysis between organizational commitment and training. My dependent variable is job satisfaction. ...
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### analysing interaction between binary categorical factors which don't explain the whole variation

I have a large dataset with 2 binary variables relating to gender & ethnicity, and one output variable, also binary. The overall incidence of the output variable is roughly 70% true. Running ...
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### Help interpreting the output from a mediation analysis

Currently I'm working on some organisational research. Just to get a bit of a idea of what I'm research; I'm looking at impact of leadership on how enthusiastically work. I believe the relationship of ...
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### Testing mediation and moderation; can one variable function as both mediator and moderator?

I am trying to understand the relationship between three variables, namely dependent, independent and a third variable I have some theoretical evidence that the third variable has mediation or ...
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### Controlling for age in logistic regression and I'm stuck in circular reasoning

I recently completed a research project that involved motor learning in control (non-disease) subjects. The outcome of the motor learning is binary: 1 - subject learned, 0 - subject didn't learn. 13 ...
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### Thesis SPSS Regression help

I'm currently working on my thesis and would like some advice for the statistical analysis section. My hypotheses are: H1: Firms that belong to a product industry are more likely to establish a ...
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### Interaction of risk factor with age in survival model with age as time scale

I'm currently looking into survival analysis regression models and can't quite wrap my head around the following: Say I want to model time to occurrence of a cardiovascular event and use age (as ...
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### Logistic regression with 2 predictive variables

I need some advice for choosing the correct model. I have 3 binary variables: Risk (0 = the person doesn't take financial risks, 1 = the person takes financial risks), gender (0 = female, 1 = male), ...
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### how to interperate the interaction?

I calculated the dummy coding for study interaction between carbohydrate dietary intake with a specific gen polymorphism. The reference group is low intake and protected genotype. the outcome of ...
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### Testing variables in meta-analysis

I am conducting a meta-analysis of cognitive-behavioural interventions on self-esteem and I could use some assistance navigating through the statistical procedures. I have extracted pre-post scores ...
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### Interpreting continuous interaction term

I have a question regarding the interpretation of an interaction term in the following model: $$Y=β_0+β_1X+β_2Z+β_3XZ$$ $X$ and $Z$ are continuous and $X$ is negatively related to $Y$, whereas $Z$ ...
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### Analysing a three way interaction

Im currently analyzing a three way interaction in R and my data looks like this: ...
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### Difference in Interaction Effect in lme4

I've the following problem which I want to analyze: Sales of a company depends on quantity of product A and B plus advertisement. All these 3 independent variables are continuous variables. Now, ...
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### 3 Interaction terms in generalized linear model

I have 4 continuous variables as my predictors (say, cognitive ability and three components of self-esteem) and the 3 two-way interactions between cognition and each self-esteem component. I am using ...
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### 2x6 repeated measures ANOVA interaction and main effects question

Currently I'm graduating and I'm finishing up my master's thesis as we speak. It's a study about the effect of hand positioning on response time. I'm submitting my data to a 2x6 repeated measures ...