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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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Software that finds correlations between loosely dependent time-series?

I'm not sure if this is the right kind of question for this site, so please let me know :) I'm looking for a time series data analysis platform, so I can take a collection of time series at 15-...
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23 views

How do I interpret a significant three-way interaction when all two-way interactions are not significant? [duplicate]

How do I interpret a three-way interaction when all two-way interactions are not significant?
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1answer
33 views

Calculate interaction effect confidence intervals in zero-inflated poisson regression

I'm conducting a zero-inflated Poisson regression using the pscl package in R. I've included interaction terms but am having an issue with interpretation. I am assuming an additive effect and summing ...
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1answer
55 views

multiple logistic regressions with binary predictors vs single logistic regression with categorical predictors

I would like to know which is statistically more advisable and what are the advantages and disadvantages of each approach. My data frame data has ...
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26 views

Independent variables and moderator variables correlate (three-way interaction)

let's assume I hypothesize: H1: A direct effect of X1 on Y H2: A direct effect of X2 on Y H3: A two-way interaction between X1 and X2 H4: A three-way interaction between X1, X2 and X3 H5: A three-...
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1answer
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Effect Modification, Confounding, and Correlation

I am trying to estimate the effect of a policy intervention (X) on patient outcome(Y) from an administrative data. In the data set, around 20% of the patients have received the intervention. Even ...
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1answer
20 views

How to interpret positive interaction term with negative individual variable effects? [closed]

Hi I have interaction term which is significantly positive while individual variable effects are both negative. Moreover the individual coefficients magnitude and significance increases after adding ...
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1answer
27 views

interaction with a mixed logistic regression using mlogit on choice data

What is the best way to analyse interactions in choice data between an individual specific variable and an alternative specific variable? I have designed a discrete choice experiment in which ...
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Interpretation of interaction terms

I try to improve my statistical knowledge and right now I am working on a regression that contains interaction terms. I am currently investigating the effects of different variables ($a_1$, $a_2$ etc.)...
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Simple effects analysis - correct univariate results for multiple comparisons?

I tested the effect of two factors with both each three levels on a DV. When analyzing my data, the ANOVA revealed two significant main effects and a significant 3x3 interaction which I now plan to ...
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Obtaining the fitted values of main effects and interactions when GLM coding is used

In short, I need to decompose the fitted values obtained from ANOVA into components corresponding to each term in ANOVA statement. This problem appears trivial, but it becomes tricky when GLM coding ...
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9 views

Comparing two difference-in-difference models when making the treatment group larger

I have a question regarding some potentially existing empirical tests in the difference-in-difference context. Assume that I have the usual setting of observing some hypothetical outcome for a ...
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Method for testing interaction in regression analysis

I am running a linear model with 6 explanatory variables (5 in classes, 1 quantitative), and would like to test which interaction(s) are eventually significant. I think an ascendant stepwise method ...
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regression analysis assessing the relationship between brain volume and behavioural score, main effect but what to do with the moderating variable?

I am conducting a regression analysis to look at the relationship between a behavioural score and brain volume. My sample is made of 2 patient groups: A and B. The model includes the following ...
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1answer
40 views

What would be the appropriate statistical test for my study?

What would be the appropriate test for a study that has: 2 categorical independent variables with 2 levels each, 1 moderator variable (and would it matter if my moderator is categorical or continuous?...
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Causal model: Controlling for moderating effect of confounder (rather than the confounder itself)

My linear regression model can be described by the following causal graph: I want to explain the sign of the causal effect of $X$ on $Y$, but unfortunately cannot measure $Z$ directly. Thus, I can ...
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1answer
43 views

Feature Interaction Strength in Catboost

I was wondering if anyone knew how the feature interaction strength is calculated in the catboost package. The documentation https://catboost.ai/docs/concepts/output-data_feature-analysis_feature-...
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Can I test for different moderation effects using several regression models or do they have to be included in one?

Let's say I have 8 independent variables A-H which I want to test for significance regarding each of their influences on the dependent variable Z. Now let's say that I additionally suspect moderation ...
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Does anyone have a reference for the assumptions of moderated hierarchical regression?

I am writing up the results of a moderated regression and need a reference for the relevant statistical assumptions. However, I am having trouble finding one. Would anyone have a reference to share? ...
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Interpreting the moderator influence from the two-way slope graphs

I am testing the moderation influence of Structural Assurance(SA) on the positive relationship between social influence(SI) which is an independent variable, and the continuance intention(CI) which is ...
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1answer
38 views

Slope is negative but confidence limits contain zero, how do I describe the effect?

I performed an ANCOVA on final height (height4) with initial height as a covariate. Dependent variables: ipc.gm = initial % cover of garlic mustard fence = factor with 2 levels: Fence, Open There ...
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Appropriate follow-up test in a 2-way within groups ANOVA

I have a 2 (time1 vs time2) x 2 (drug blood concentration: resting vs. post-exercise) within subjects design. I want to know if the difference between post-exercise and baseline is different at each ...
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Is this the correct way to interpret odds ratio for three way interaction?

grateful for any thoughts about this. I'm doing a generalized linear model analysis of a binomial dependent variable (whether the participant gets the correct answer or not). I have three ...
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ANCOVA significant interactions in R: How do I interpret slopes from interaction plots?

I've got a continuous dependent variable height4, a continuous covariate height, a continuous dependent variable ipc.gm, and a factor fence with 2 levels: Fence and Open. I've got a significant ...
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Significant interaction in Mixed-design 2-way ANOVA. How to correct for multiple comparisons?

I have conducted a mixed-design two-way ANOVA (between subjects variable : 2 levels; within subjects variable : 8 levels). I have a significant main effect of between and within subject variables and ...
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How to compare growth rates estimated from GLMM?

I've counted aphid populations under 5 different treatments for about 10 weeks. There were 4 replicates of every treatment. I'm interested in comparing the first 4-5 weeks, where the populations ...
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Interpreting OLS regression with continuous interaction?

I'm a beginner when it comes to statistics and I have a question about how to interpret the results of this OLS model and specifically the interaction of two continuous variables. The following ...
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1answer
36 views

Interpreting categorical interaction terms

I am wondering how to interpret results of interaction terms (see image below). I think to know that the interaction term 1 (IV x potential moderator group 1) depicts the difference of association ...
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1answer
33 views

Testing two potential interaction variables (or potential sources of effect heterogeneity) against each other

I have an experiment I have run, and I am testing for heterogeneous treatment effects (pre-registered and not fishing for any particular result!). Let's call the outcome $Y$ and the treatment variable ...
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14 views

Analyse interaction/moderators first and then adjust for confounding

In my research I am interested in subgroup analyses. I am looking at a general association between two variables (environment and health outcome) with interaction terms (personal factors, which are ...
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0answers
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How to interpret a two-way interaction in a 3-way interaction model

I am trying to predict y with variables a, b and c. I have two models and I get different results depending on how I fit my model. Model A is the simpler model, in which I exclude variable c. In ...
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3answers
74 views

Multiple regression with dummy variables and interaction term

We have done a multiple regression analysis to see how gender and experience affect salary. We used a dummy variable for gender and then we also added the interaction variable (female work experience)....
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Interpreting interaction effect between two categorical predictors using linear mixed model

I have read other threads regarding this topic, however, I haven't come across a results table that looks similar to mine (below) so I am seeking some clarification. I am using MIXED (SPSS v25) to ...
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Comparing Logistic regression Pseudo-$R^2$ between model with Interaction effects and model without Interaction effects

I have two Logistic regression models, one including manually selected (hierarchical) interaction effects between few independent variables and one model without any interaction effects. Both models ...
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Are conditional effects the same as main effects when using orthogonal contrast codes for categorical predictors?

I ran into a presentation discussing the difference between conditional (or simple) effects and main effects when interpreting regression output in the presence of interaction terms. http://www.lrdc....
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Three-factor ANOVA

I’m analysing a dataset on contents of flavonoids in different parts of a plant (factor A: leaves, flowers, stems), during different phases of plant growth (factor B: vegetation, full flowering, ...
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Assess impact on results of participants recruited via additional outreach efforts

I am currently working on a project that evaluates certain study recruitment strategies in regards of increasing participation among different subgroups. One of those strategies is reminder letters. ...
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What is the best way to choose interactions between continuous variables for Logistic Regression?

I have a logistic regression model that I am working on for a school project. I have about 55 predictors, all of which are continuous. I am relatively new to the idea of "interactions" between ...
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Linear regression Interaction Quadratic terms

In linear regression, if I have dependent variable Y and independent variables A and B, where B has a quadratic relationship with Y, and I'm looking for a possible interaction between A and B, I would ...
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What information can be extracted from plotting two variables of a multiple logistic regression against the prediction?

I have a multiple logistic regression model that has the form of: disease ~ treatment + x2 + x3 + x4 + x5 Where disease can take values 1 and 0 (diseased or not ...
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1answer
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Significance of the sum of the main effect and interaction term

Consider a simple linear regression with an interaction term: $Y=b_0 + b_1X +b_2Z+b_3XZ$ where $X$ is continuous and $Z$ is a dummy. I want to find out whether $X$ has a significant impact on $Y$ ...
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Main effect changes after adding interaction term [duplicate]

I have two models: Model 1: Y = b0 + b1X1 + b2X2 + b3X3 Model 2: Y = b0 + b1X1 + b2X2 + b3X3 + b4X2X3 all coefficients are significant in both models but b2 changes from positive in "model 1" ...
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1answer
36 views

multicollinarity issue

I ran a logistic regression moderation analyses and I noticed that with the addition of the interaction term, one of the predictors flipped signs. The variable (X) was previously -.015 and became .006 ...
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1answer
20 views

Is it possible to include an interaction term in logistic model if the interaction term had no observation in some category?

I tried to do a binary logistic regression. y was a binary outcome x1 was an independent variable by 5 categories x2 was an independent variable by 2 categories I found that x1 and x2 had the ...
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1answer
107 views

Does correlation between variables in an interaction matter?

Suppose you fit a model $y = x_1 + x_2 + x_1\times x_2$. Are there any practical implications for estimation of the interaction effect if $x_1$ and $x_2$ are correlated? I understand there could be ...
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1answer
56 views

Interpreting interaction with quadratic term

$Y$ (scores among black students) $\sim X_1 + X_1^2 + X_2 + (X_1 * X_2) + (X_1^2 * X_2)$ ...
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1answer
42 views

Different regression coefficients from statsmodels OLS API and formula ols API

I work at a relatively large Swedish retail company where I am currently performing initial linear regression in order to understand the linkage between dependent variable store sales (number of ...
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0answers
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Interpretation of two dummy variables in interaction with addition of new variables

I have a mixed effects model with an interaction between two dummy variables. Y variable is continuous. My questions: Does the interpretation of the variables included in the interaction (and the ...
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Finding Null distribution for gbm interactions

I am trying to determine which interactions in a gbm model are significant using the method described in Friedman and Popescu 2008. My gbm is a classification model with 9 different classes. I'm ...