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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How to code effect modifier in a Cox Regression using R?
The definition of the distinction between the effect modifier and interaction term is:
Interaction and effect modification are formally defined within the counterfactual framework. Interaction is ...
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1answer
19 views
Interpreting dummy variable interaction terms
I am attempting to model monthly retail electricity sales. To account for both the effects of seasonality and weather, I created an interaction term by multiplying 12 monthly dummy variables by the ...
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0answers
19 views
Interactions terms and the dummy variables
I am attempting to model monthly retail electricity sales. To account for both the effects of seasonality and weather, I created an interaction term by multiplying 12 monthly dummy variables by the ...
2
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1answer
30 views
When non-significant interaction effects make a significant main effect non-significant [duplicate]
Suppose that I have two IVs (AnxietyLevel & experimental conditions (dummy coded as 0 and 1), and two control variables (Age & Gender) and one DV (mean score on a questionnaire). And I am ...
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1answer
148 views
How to include an interaction with a quadratic term? [on hold]
I want to predict $y$ with $x_{1}$ and $x_{2}$ and I suppose that $x_{2}$ has a quadratic effect on $y$ and that there is an interaction. How to model that?
I've look in previous questions but there ...
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0answers
28 views
Interaction significant, simple effects not
I'm running a regression which showed a significant interaction effect between my variable design (0,1) and device (0,1) on view time. However, i did not found a main effect of design on view time. ...
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0answers
10 views
Simple slopes analysis for regression with user defined contrast codes [on hold]
I am struggling with conducting a linear regression with user defined contrast codes and simple slope analyses of significant interactions between the contrast codes and categorical and continuous ...
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0answers
28 views
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). This variable Y is a continuous variable ...
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0answers
16 views
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
25 views
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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0answers
21 views
Integrals simulation in the program R [closed]
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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1answer
39 views
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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1answer
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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0answers
55 views
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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1answer
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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0answers
14 views
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 ...
1
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1answer
17 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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0answers
14 views
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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0answers
14 views
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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0answers
28 views
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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0answers
12 views
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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0answers
18 views
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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0answers
48 views
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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0answers
16 views
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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0answers
9 views
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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0answers
8 views
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
27 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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0answers
15 views
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
33 views
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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0answers
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
116 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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0answers
10 views
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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0answers
6 views
Using random forest to generate interaction terms for linear regression [on hold]
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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2 views
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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0answers
24 views
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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2answers
224 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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0answers
3 views
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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0answers
12 views
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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0answers
8 views
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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0answers
28 views
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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0answers
11 views
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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0answers
17 views
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
26 views
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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0answers
11 views
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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0answers
10 views
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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0answers
17 views
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 ...
