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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9 views

Controlling for interaction between IV and covariate using PROCESS? [on hold]

I am struggling to find a solution to this problem. My research model is simple: X = (manipulated) categorical IV M = (measured) continuous moderator Y = continuous DV I have analyzed this model ...
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11 views

Regression: checking effect of negative vs positive regressor

I'm fitting a linear model of the following form: $Y_{i} = \alpha + \beta_1X_{i} + \beta_2Z_{i} + \beta_3X_{i}\times Z_{i}+e_i$ All the variables are continuous. I'm interested in the sign of the ...
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Using a group-level mean as a predictor in a mixed effects model

I want to fit a multi-level model across $j=1,2,3,...,k$ groups that predicts $y_{ji}$ for the ith observation in the jth cluster. $ Y_{ji} = \alpha_j + \beta_1 X_{ji} + \beta_2 \bar{X_{j.}} + \beta_{...
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How interaction terms are treated in Gradient Boosting?

In GAMs interaction terms have to be expressly specified as covariates, even for simple linear relationships. On the contrary, with Gradient boosting this is not nesessary because the algorithm itself ...
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Interaction, Coefficients and Confidence Intervals in R [closed]

I am running a logistic model in R that looks like this (all variables are binary): ...
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12 views

Standardizing predictors for Neg Binom Regression

tl;dr: If I include an interaction term in Negative Binomial Regression, should I standardize the predictors? I am analyzing a very large dataset (over 60 million observations) that has the following ...
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Need a help on interpreting Linear regression outputs of two models - with and without interaction

How to interpret the output following 2 regression models? Why AHI.x and BMI is not significant in the ...
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112 views

Why am I getting a different intercept in my regression model with categorical variables when I let them interact?

I'm comparing two regression models in R. Both use the same categorical variables the only difference is that in one I allow them to interact, the other I don't. ...
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22 views

Moderated regression in the context of an experiment

I have an analysis $Y = β_0 + β_1X_1 + β_2X_2 + β_3(X_{1} \times X_2) + \epsilon$ , in which: $Y$ is a continuous outcome variable $X_1$ is a continuous predictor (it can be thought of as a type ...
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For interactions, how do I find when values of the DV are significantly different from one another?

Ran a continuous interaction that was significant. I centered the IVs and plotted the interaction with 2 regression lines(-1SD and +1SD of the moderator). A reviewer asked me to update my interaction ...
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Analysis of interaction with multiple levels in each factor (emmeans in mixed model)

I ran an experiment with treatment (3 levels: ctrl, A, B) as a between-subject factor and environment (4 levels: 1, 2, 3, 4) as ...
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Not including main effect term in subgroup analysis?

I know there are plenty of previous Cross Validated posts regarding if one must include the main effect term if the interaction term is included. The general consensus is: no if you have a very good ...
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27 views

Question about collinearity interaction

I'm running logistic regression for outcome on SBP (systolic blood pressure), DBP (diastolic blood pressure), BMI, and other covariates. Because SBP, BMI didn't show linear relationship with logit of ...
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How to compare LME regression coefficients across models with same variables but different sample sizes/trial numbers?

I have a quite specific situation that does not seem to be covered by other, similar posts: I ran a study where a task (Task A) was periodically interrupted by a probe that asked participants what ...
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Nonsignificant interaction? [closed]

So, consider a model with variables a, b, and the interaction of a and b. The interaction is not significant. I understand that you can interpret a as the effect of a when b=0 and I can recenter ...
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Moderation analysis through Hayes process

In moderation analysis, interaction effect is significant and direct effect of moderator is also significant, but conditional effects of focal predictors at the values of moderator is insignificant. ...
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33 views

Influence of Interactions

I am simulating the following model on R: $X_1, X_2\sim \mathcal{U}(-1,1)$ $$Y = b_1X_1 + b_2X_2 +b_{12}X_1X_2 + \epsilon$$ $\epsilon\sim\mathcal{N}(0,\sigma^2)$ I am running code on R to ...
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Logistic regression: Interaction continuous/categorical variables and multiple comparisons

I am fitting a logistic regression model with two independent variables, one continuous (length, here lun) and one categorical (Year = 2013, 2014, 2015). My dependent variable is the maturity stage of ...
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lsmeans diff of a variable involved in an interaction

I have a variable that is a simple 0-1 variable in a class statement. It is also involved in interactions. In the model this class variable is not significant and I understand that I shouldn't ...
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28 views

interpretation of interaction effects in a Cox-regression

I am attempting to interpret results of my R output, especially interaction effects. My analysis includes several models (2 of them shown below), at which I always have a metric Variable (in the ...
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1answer
78 views

Formula to Calculate Confidence Interval of Marginal Means

What is the formula for the marginal means confidence interval in a regression analysis? Let us have the following regression $Y = b_0 + b_1X + b_2Z + b_3 XZ + b_4 Cov_1 + b_5 Cov_2$ If I get it ...
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19 views

Interactions between categorical and continuous independent variables

Im going to investigate if a disease have a negative impact on the development of children. The disease is the independent variable with additionally 10 confounders. Do I have to check for ...
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Plotting simple slopes in RMANOVA?

I have an experiment that measures behavior across 4 blocks. I have a between-subjects continuous physiological variable that interacts with this block effect: physiology x quadratic block effect. I ...
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Intuition Behind Johnson-Neyman Interval in Moderation Analysis

What is the simple intuition behind the Johnson-Neyman Interval? I created a J-N plot as follows: Is it simple enough to say that the interaction (in this example two continuous variables [I have hid ...
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35 views

Determine relationship across two variables in simulation result data

I need help, but I do not know the specific terms that describe what I want to do, but I will explain as much as possible. It is most likely the reason that I have not been able to get what I want, in ...
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26 views

Simple Slopes Analysis Intuition

I have found a significant interaction with two continuous variables. I proceeded to create simple slopes graphs as recommended by Preacher (i.e., - 1 SD, mean, and +1SD slopes). What exactly to ...
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Interaction terms in regression when variables can be negative

Suppose I have a regression $y = b_0 + b_1 x_1 + b_2 x_2 $ where both $x_1$ and $x_2$ have a range from $-\infty$ to $\infty$ and have been centered. The correlation between $x_1$ and $x_2$ is $0.3$...
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Moderation: moderation where there is no main effect for moderator on DV

I have run a moderation analysis using PROCESS. The model examines whether 'time' moderates the (IV) intention- (DV) B5 relationship. My model is significant overall. Intention and the interaction ...
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What is the difference between moderation and adjustment

What is the difference between moderation and adjustment in regression analysis? How can I conduct each of them in SPSS? I would appreciate any type of help. Thanks..
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How do I interpret this interaction between a continuous variable and a binary variable from a log binomial model?

I'm new to modelling and not sure how to interpret this interaction for a results section. The model output tells me that the interaction between cancer (binary) and age (continuous - one year ...
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62 views

Are interaction terms commutative?

Im trying to understand interaction effects a little better. My question is, if I have a model that's described by: $y = \beta_{0} + \beta_{0}x_{1} + \beta_{0}x_{2} + \beta_{0}x_{1}x_{2} + \epsilon$ ...
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28 views

Feature Engineering for Multiple Regression

My goal: I want to predict a single output value from multiple inputs, some of which are numerical and some of which are categorical. To do this, I plan on building a multiple-regression model (...
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Interpreting interaction effects in Factorial design

I have factor1 with 2 levels fully crossed with factor2 (5 levels). Now samples are collected from same experimental units at 6 different times. Time is used as within-subject variable. When I run ...
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If parallel trends assumption is not met for diff-in-diff analysis, why not add more interaction terms to regression model?

The literature presents a violation of the parallel trends assumption as a major obstacle when performing a difference-in-differences analysis. Why can't we model non-parallel trends by simply ...
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What is the meaning of the beta for the interaction between continuous variables in a linear mixed-model?

If I create a mixed-effects linear regression model similar to the following (using the lme4 package in R), where all of the fixed effect variables are continuous: ...
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Cox regression with numerous interaction terms

I am fitting a Cox regression model using the coxph() function of the survival package in R. I have 15 predictors. One of the predictors is treatment (given / not given). The treatment is a well-...
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Moderation vs adjustment in statistics

Can anyone tell me what is the difference between moderation and adjustment in statistics? And who to conduct each of them in regression analysis using SPSS? I would appreciate any help.
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43 views

Unexpectedly large coefficients in logistic interaction model

I would like to know if you could provide any insights regarding large and unexpected coefficients in logistic models with interaction terms. When running the interaction model, the coefficients for ...
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6 views

Multi level logistic regression with ordinal level dependent and independent variables

I am currently trying to run a multi level logistic regression model and struggling to identify the best way forward using STATA.Details below: Independent variable: ordinal with 5 levels Dependant ...
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Is it necessary to adjust for multiple comparisons (e.g. Bonferroni) when using continuous interaction terms (e.g. age)?

I am interested in analyzing how the effect of a dichotomous variable on a dichotomous outcome changes by age. In reading this how-to article from UCLA's Institute for Digital Research & Education-...
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interpreting a log-log-linear model of two continous variables with or without interaction terms

I am regressing ecological distances between communities (as expressed as similarity) over their spatial and temporal distance on a regular grid of 360 sampling stations divided over six time points. ...
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PROCESS moderation - significant interaction, but non-significant effects at both values of the moderator

I'm testing the hypothesis that W moderates the effect of X on Y. The PROCESS output has indicated a significant X*W interaction under 'Test(s) of highest order unconditional interaction(s)' (p = ....
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Interaction between Ordinal and Dummy Variable?

Hello ladies and gentlemen, I am interested whether an existing effect is altered by the levels of another effect. As far as I know, including interaction variables is an appropriate way to explore ...
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1answer
26 views

Is it ok to use control variables in a moderator/interaction analysis in experimental design?

I have a question concerning the inclusion of control variables into my research. I have data from an experimental, randomly distributed social protection program. I want to test whether a moderating ...
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How to Illustrate Continuous-Continuous Interactions

What is the best way to illustrate an effect modification from a general linear model? I can use GraphPad Prism or R; can anyone point me resources showcasing how to produce publication ready plots ...
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1answer
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Conducting a subgroup analysis with regression modeling

I'm conducting a survival analysis using Cox Proportional Hazards regression to identify prognostic factors for cancer patients. My covariates include information such as age, sex, tumor location etc. ...
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Heteroscedasticity consistent (HC) standard error analysis and interaction effects in an OLS

I have made a model with several variables, and 8 of them interact with a dummy to find interaction effects. These are added stepwise, resulting in three models. Now, through a Breusch-Pagan test I ...
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Will the main effect of two binary independent variables change when I enter them in a regression with their interaction term?

If I have two dummy independent variables (both binary, with two levels each) in a regression, then how do I construct the the interaction variable? By coding both variables as (1,0) and multiplying ...
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Interpret continuous x continuous interaction

I am trying to describe the interaction term you can see below in the image. I know that I can do a median split of the potential moderator in order to get the slopes per group. I am however also ...
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1answer
25 views

How to interpret categorical variable significant ANOVA interaction in R?

I have this output from a R ANOVA analysis and the graph attached. I want to verify if the interpretation for the scenario is correct? ...