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

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22 views

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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0answers
30 views

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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40 views

Interpreting non-significant simple slopes

I did a hierarchical multiple regression with a few hypothetical variables X=trait control, M=exercise and Y=happiness. X and M were insignificant but the interaction term was significant. After ...
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0answers
10 views

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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27 views

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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12 views

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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1answer
11 views

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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13 views

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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10 views

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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45 views

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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1answer
52 views

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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30 views

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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24 views

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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2answers
65 views

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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27 views

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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15 views

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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1answer
41 views

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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0answers
22 views

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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13 views

Analysing a three way interaction

Im currently analyzing a three way interaction in R and my data looks like this: ...
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1answer
20 views

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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1answer
29 views

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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0answers
12 views

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 ...
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9 views

Is there a way to test if moderation occurs across DVs?

Say I have two regression models with the same explanatory variable (e.g., income) but with different outcomes that have been measured on the same scale (e.g., 0-10, positive and negative affect). Is ...
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0answers
38 views

Prediction using fixed effects in glmm

I have the following generalized linear mixed effects model (mcmcglmm in R) with data based on this paper. Sex is a two level factor (M or F), ...
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26 views

GLM: Is it necessary to include lower-order interactions when testing higher-order interactions

It appears to be a general principle that one should include all main effect terms when modelling interactions in (generalized) linear models (as argued here, for example: Including the interaction ...
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19 views

How to deal with interaction between several dummy variables and one continuous variables in one or two regression models?

I want to know the relationship between revenue and cost in several conditions. Dependent variables is REVENUE.REVENUE is a continuous variable from 0~1000+.I have several key independent variables: ...
2
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1answer
28 views

'moderator' analyses in a meta-analysis

Sorry if I use the wrong terms here, I am still learning how to do this. I am conducting an meta-analysis comparing two treatment types, using Cohen's d. I have completed the primary analyses of the ...
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2answers
32 views

Difficulties fitting a Cox PH model with categorical interactions to complex survey data

I'm attempting to fit a Cox proportional hazards model to a set of NHANES data; the code to load and clean the data is here, and the resulting dataset is here. The difficulty I'm having is ...
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8 views

Simulating qualitative interaction in survival analysis

I am trying to simulate the survival data that can fit the model: $$h(x) = ho(x) exp (a_0*Treatment + a_1*Treatment*x_1 + a_2*Treatment*x_2)$$ Whereas treatment is an binary variable (0 = control ...
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1answer
16 views

Test of interaction in logistic regression

I know that it's pretty much impossible to test out all the combinations of interaction with sufficiently many predictors, but if I were to suspect some interaction between two particular predictors ...
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0answers
7 views

Simulating interaction term in Cox model

I am trying to simulate the survival data (by using Weibull distribution) that can fit the Cox model below: h(t) = ho(t). exp(beta1 * X1 + beta2 * X1 * X2) X1 and X2 are binary. I haved tried using ...
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1answer
18 views

sub sample versus indicator variables (multiple regression)

In my study I have an continuous dependent variable (return) regressed on an independent continuous variable x1 (momentum) and a number of control variables. I am currently investigating whether this ...
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1answer
23 views

What is the difference/relation between variables that are multicollinear, confounding, interacting

What is the exact difference between two variables that are multicollinear and two variables that are interacting and two variables that are confounding? Are they multiple meanings for the same thing?...
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1answer
21 views

Estimating coefficients of an interaction in a GLMM with R (lme4)

I fitted a Generalized Linear Mixed Model with a Gamma distribution of errors on lme4. I included an interaction between two continuous variables (x:z). How can I estimate the coefficients (beta, ...
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1answer
66 views

> 1 interaction variable, single regression versus multiple regressions

In my study I have an independent continuous variable x1 (momentum) and four dummy variables D1 D2 D3 D4 which indicate industry type. I am investigating the four interaction variables between the ...
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8 views

Multivariate regression, non-normal response variable

I am attempting to run multivariate regression model with interactions terms to understand the combined effect for categorical variables and 2 other continuous variables. My response variable is ...
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23 views

Why is it recommended to delete interaction terms “as a chunk”?

In this answer it was discussed that when terms are being deleted for the purposes of model simplification, it's best to delete terms "by chunk". That is, in an x1 * x2 * x3 * x4 scenario we'd ...
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0answers
31 views

Including 2-way interaction dummy variables in binary logistic regression

I am trying to do a binary logistic regression by including 2-way interaction where I have two drug dosages types each taking two levels (high and low) and dependent variable is categorical cancer ...
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0answers
20 views

Interpretation of Interaction effects in a Binary Logistic Regression

I have a series of exam practice questions on binary logistic regression, and I am struggling with one because I am unclear on how to interpret interaction effects in binary logistic regression. In ...
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26 views

Constructing A Simple Hypothesis

In the book Applied Longitudinal Analysis, 2nd Edition there is an example in the chapter "Marginal Models: Generalized Estimating Equations (GEE)" in "Muscatine Coronary Risk Factor Study" sub-...
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1answer
32 views

How to interpret interaction between categorical and continuous variable?

I have a question regarding the analysis/interpretation of a significant interaction between a continuous variable and a categorical variable, which seems pretty easy but I just don't understand it ...
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0answers
16 views

how to interpret interaction in Poisson regression using SAS

I tried to run Poisson regression models using SAS by including interaction terms and offset by log population. All dependent variables were categorical. In the first model, I tested the interaction ...
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2answers
56 views

Product factor in R. What's the interpretation?

So I am reading an R guide which tells me that the product factor $B \times T$ is implemented in $R$ by using the $*$-operator on the factors after $\sim$. However, when I check the model matrix for ...
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12 views

Interpreting multiple (additive) moderators

I have a regression model with four continuous predictors: two main variables (X, Z) and two moderators (M1, M2). I hypothesize each of the moderators to interact with both of the main variables ...
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26 views

Multiple linear regression interactions

When plotting the effects of two factors on the dependent variable, why do parallel lines like the ones illustrated in figure 44 show that there is no interaction between factor (i) and factor (j)? I ...
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49 views

Interpreting interaction term that only includes some of the variables in the model

I have a multinomial regression model with 5 variables (forced to enter the model), and all 2 way interactions between those variables (forward stepwise). The variables are: age, education level, ...
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12 views

Post hoc ttest in SPSS

I computed a A x B (2 x 2) within subject ANOVA for a given ROI using repeated measures GLM. The interaction between A and B was not significant, but two main effects were detected. Can I still ...
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1answer
15 views

Modelling a polynomial interaction

Say I have a model with one response variable ($y$, a continuous variable) and two predictor variables ($x_1$ & $x_2$, both continuous). My model includes both the additive effects of these ...
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0answers
22 views

Comparing groups with linear-mixed models

I have a problem with a dataset resulting from the repeated measurements of a clinical index on different patients. Each patient has been classified into two groups according to the index decline two ...