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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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Longitudinal mixed-model with co-varaites

I'm currently have a longitudinal dataset with dependent variable Y measures over two time points (variable = Time) across 4 groups (variable = Group). I want to take account the variability of each ...
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simr power simulation testing interaction term for 2 factors

I have a model with two factors: a (4 levels) and b (3 levels). Each participant receives two problems (id as a random effect). I want to estimate sample size based on pilot data to give me ...
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1answer
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How do you use panel data to isolate the relationship of interest for a particular individual within your panel?

I have a panel data set where Canadian provinces are the individuals. (I have annual data from 1997-2017). I am using a random effects model to see the impact of an explanatory variable $X_{it}$ on ...
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Integrals simulation in the program R [on hold]

Given the simulation with the R program, show that the integral is below $\int_0^{\sigma^\pi (x)} x^2 \lambda e^{-\lambda x} d x =1/2$ . Assumptions of the problem let $x|\lambda \sim exp (\lambda) \...
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help interpret interaction effect in linear mixed effect

I am trying to predict response time (transformed in Log) from Group (a factor with two levels: NS and NNS), and Time of Testing (a factor with three levels: Pretest, Posttest, Delayed-test), using ...
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27 views

Interpret contradicting output of lmer model with categorical interaction in R

I am struggling to interpret my output in R. It does not make sense to me. I first regressed participants' ratings (= value) on manipulations (...
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Calculate odds ratios and P-value for interaction across multiple separate subgroups

I'm trying to understand/replicate an adjusted logistic regression analysis where a treatment effect is estimated separately in a number (>2) of subgroups and estimating an overall P-value for ...
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28 views

How powerful are second order interactions?

A lot of applications in statistics and machine learning model a phenomenon by second order interactions of variables and get good results. By second order interactions I mean, for a general variable $...
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2answers
29 views

Bayes factors and predictive accuracy in model comparison in rstan / brms

Despite reading up on the subject, I can't wrap my head round it, so the question remains on shaky grounds, and responses along the lines of "read chapter x" are very welcome. What I'm doing is I'm ...
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similar risk estimates between groups but have significant interaction

I am running a cox proportional hazard model to analyze the association between air pollution and risk of mortality. In the subgroup analysis, I obtained some confusing results. For example, when ...
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1answer
15 views

Visualize cross over interaction logistic regression categorical variable in R

I have performed a logistic regression with the following variables: X: Categorical with three levels (St, An, Int) M: Moderator, which has two levels (Mob,Desk) Y: Dichotomous dependent variable (0/...
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ANCOVA: resolving hetrogeneity of regression slopes with multilevel modelling vs adding an interaction term

On the Wikipedia page for Multilevel model it is written that [M]ultilevel models can be used as an alternative to ANCOVA, where scores on the dependent variable are adjusted for covariates (e.g....
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Estimating weights in the assignment problem

How would you learn a function with the emphasis on feature interactions? I have the standard assignment problem: $$ \max_{x_{ij}} \sum_{(i, j)} w_{ij} x_{ij}, $$ where $w_{ij}$ is the weight of ...
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Testing interaction terms individually and simultaneously

I am currently testing two interaction terms individually in OLS regressions. Both interaction terms are significant (p < .5) when tested individually (i.e., two regression equations, one for each ...
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non homogonous data and interaction

I have an experiment design with: Variable 1 - 2 levels Variable 2 - 3 levels And demographic information collected about my participants: Demographic 1 - 2 levels Demographic 2 - 3 levels ...
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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 ...
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1answer
78 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 ...
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Using a t-test to follow-up on a non-significant interaction in an ANCOVA?

My question is about whether a t-test can be used to follow-up on a non-significant interaction found with an ANCOVA. I have an experiment that compares the impacts on students' learning (as measured ...
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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+...
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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 ...
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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 ...
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1answer
26 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 ...
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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 ...
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1answer
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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) * ...
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1answer
23 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 ...
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9 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 ...
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3answers
114 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 ...
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1answer
24 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 ...
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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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Using random forest to generate interaction terms for linear regression

What I want to do is: Setting random forest's each tree to be very shallow, probably 2 levels, or 3. Then I will create 100 trees. After that, I will use each tree's result as a predictor, and then ...
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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 ...
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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. ...
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215 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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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. ...
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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 ...
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1answer
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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 ...
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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 ...
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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....
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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 ...
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2answers
97 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: ...
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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. ...
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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 ...
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0answers
20 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,...
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16 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 ...
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1answer
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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 ...
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1answer
64 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 ...