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

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1answer
56 views

Plot regression with interaction in R

I did a regression analysis with the following variables: Predictor = dummy variable, dependent Variable = metric, moderator variable = metric. I now want to show my results in a figure. The ...
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0answers
16 views

minitab p-values of interactions

I am having some trouble in Minitab. I constructed a L16 Taguchi orthogonal array for 5 factors which all have 2 levels by using Minitab, and I need to check if all the interactions are significant or ...
5
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4answers
170 views
+50

Nonlinear effect in an interaction term

If you have B, which is a 0/1 outcome variable, S, which is a continuous variable, and ...
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1answer
15 views

Mean separation when interaction is significant

I am analyzing a factorial experiment in RCBD (3 cultivars x 4 inoculation methods with 10 replicates). All main effects and interactions are significant for a particular response variable. But in ...
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2answers
95 views

Does triple interaction need to include all main effect variables?

I have a triple interaction: AxBxD, where A and B are continuous variables and D is a dummy. My regression is Y = A + B + AxB + AxD + AxBxD In this case, do I HAVE TO include BxD also? In theory here ...
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0answers
13 views

Can dependent variables appear in interaction terms in a system of simultaneous equations?

Given a system of 2 equations with y1 and y2 the dependent variables: \begin{align} y1 &= a0 + a1x1 + a2(x2y2) + ... + e1 \tag 1 \\ y2 &= b0 + b1x1 + b2(x2y1) + ... + e2, \tag 2 \end{align} ...
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0answers
9 views

Code to create interacting dummy variable [migrated]

I'm very new to R and am trying to interact my dummy variable with an explanatory variable and don't know how to do this. Apologies if I've not formatted this the right way but I'm new to this site as ...
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1answer
28 views

dummy variables, interaction with continuous variable, and variable selection

I want to predict shop sales from a set of independent variables which consists of shop attributes like floor space, no. of stuff of a specific store (continuous variables) and also location of the ...
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1answer
42 views

Can site be used as a factor in a multiple regression model?

I am studying two sites with different fertility and soil texture. In the model I used the data from both sites. I would like to know if could I could use the site as a factor (variable) in the model? ...
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0answers
9 views

interpreting Interaction 3 way interaction [duplicate]

What is the simplest way to understand three-way interactions? My interaction was negative and main effect was negative. Other interaction was negative and main effect was positive.
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0answers
18 views

Model-selection and interactions: Glmnet dropping underlying terms

I have a dataset and want to do an Ancova with several explanatory variables (several factors and two covariates) and their interactions. I want to select the best model using glmnet and lasso ...
4
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1answer
45 views

Account for multiple treatments to the same subject when the treatments are a numerical variable

254 individuals were asked their purchase intent of a product (on a 1-5 scaled) at different prices \$699, \$799, \$899, \$999, and \$1099. The data looks like: ...
2
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1answer
36 views

Is it better to remove higher order interactions or least significant terms first in model simplification?

I have a mixed effects model with 3 explanatory factors and a full interaction set (including 3 way interaction). This is the full model. Factor 1 is time and I am interested in the change in the ...
2
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1answer
56 views

three-way-interaction between two continuous and one binary variable using OLS stata

I'm facing difficulties in interpreting a three-way-interaction term. I'm using OLS and the three-way-interaction term is significant. Y is the response variable (continuous), X the predictor ...
0
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0answers
29 views

Two basic questions on hierarchical/multilevel modeling re: specific term interpretation and when to use in general

Suppose a hierarchical model with varying intercepts and varying slopes, with a single individual-level predictor $x$ and a single cluster-level predictor $z$. After inserting the level 2 equations ...
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0answers
40 views

To use Interactions or to split the sample?

I have panel data for 16 years and 134 countries. I am using fixed effects model and using following regression models: Model 1: $y = \beta_0 + \beta_1 X_1 + \beta_2 X_2 + \epsilon $ Model 2: $y ...
3
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1answer
56 views

Kruskal-Wallis and Ordinal Logistic Regression

Many relate Ordinal Logistic Regression (OLR) with Kruskal-Wallis (KW) in the sense that OLR may be used when there are two or more IVs and interaction effect between them are of interest, while KW ...
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1answer
23 views

Interactions - using ratio of variables

I have 3 variables, colony size, colony age and growth rate (colony size/age). I am interested to predict various other properties ($y$) of a colony using these 3 variables; $y = a_1 \text{ size} + ...
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1answer
64 views

Curvilinear relationship with moderator

I am trying to moderate a curve and determine which equation I should follow. A simple curvilinear relationship has the following equation: (1) $Y = b_0 + b_1X + b_2X^2$ (i.e. a linear term and a ...
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2answers
40 views

Imputing using CFA for use in a Cox regression

I am using CFA (confirmatory factor analysis) to create a measurement model of social capital that is to be used in a Cox regression. Because of missing data I first impute the incomplete data by MICE ...
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0answers
12 views

Performing interaction with a very significant predictor drives down p val of other predictors. But does it makes sense?

I'm observing a phenomenon that I can't understand. I have a linear regression setting with categorical vars. A couple of these elicit an highly significant coefficient and low p values. When used ...
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0answers
32 views

PROCESS (Hayes) by using IV categorical

I am trying to run a moderation using SPSS with Hayes'macro. But I have a IV with 3 categories (a,b,c). In his page Hayes gives this explanation (see below) but I am not sure how to do this using ...
2
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1answer
16 views

What's the best way to model two insurance categories that are non-exclusive?

I am modeling insurance status in a logistic regression as separate dummy variables for private, Medicare, Medicaid, uninsured, etc. For people that are dual eligible, should I have a separate "dual ...
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0answers
12 views

How to analyze the interaction of temperature and PM on mortailtiy? [closed]

library(dlnm);library(mgcv);library(splines);library(tsModel) the model for main effect,(R code) ...
2
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2answers
27 views

Can a continuous effect modifier be categorized into quartiles? [duplicate]

Is it statistically sound to dummy code a continuous variable (effect modifier) into quartiles and compare the odds ratios of an IV vs. DV in Q1 and IV vs. DV in Q4 in logistic regression? If so, how ...
0
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1answer
41 views

Multi level regression with interaction using R lme4

I'd like to do a regression analysis with interactions, my data has two levels (school classes and pupils). My variables are: Predictor = dummy variable on Level 1, dependent Variable = metric on ...
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25 views

how do we know if interaction effect exist between two continuous variables

I have a dependent variable (y) and three independent variables X1, X2, and X3. The correlation table shows that each of these independent variables has significant positive relationship with Y. But ...
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3answers
44 views

creating interaction term for dummy variables and categorical variables

I want to create interaction term by using dummy variables and categorical variables. For example, if I want to create interaction term by gender(0=male, 1=female) and education level(0=less than ...
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2answers
103 views

Multiple regression analysis - using all possible interactions

I have data on about 8000 persons and I am trying to find independent predictors of a health outcome variable (yvar). The predictor variables are age, gender, height, city and 3 other predictor ...
0
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1answer
119 views

How to interpret “main effects” in a GLMM?

Recently, I asked a question about what procedure to use to analyse mixed data with dichotomous outcomes, see [here][1]. Now I started running some first analyses (mainly with SPSS, but I'll post the ...
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0answers
55 views

In R package lme4, how do you force the random slopes and intercepts to be uncorrelated for an interaction term?

I have a mixed model, fit using lmer in R, that has three interaction terms (X1:X1, X1:X3, ...
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0answers
90 views

Meta-analysis of percentages at baseline and follow-ups in R using metafor package

I would like to conduct a meta-analysis in the context where I have studies available that measure a continuos variable at multiple time points (0, 1, 2, 3, 4, 5). Time 0 represents the baseline where ...
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8 views

Including an interaction term in GLM with full factorial experiment data

I collected data from an 2 X 2 X 2 full factorial experiment. Because a DV is a count variable and unequal mean and variance, I ran a Negative Bimonial Model. It was hard for me to come up a good ...
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1answer
14 views

Prediction on Interaction Terms in Multiple Linear Model

I have created a MLR model where my predictor variables are continuous and categorical. I am interested in the interactions between the categorical variables. Let's say I have the response variable ...
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21 views

3-way repeated mesures ANOVA

I conducted reaction-time experiment with three factors - set size (4, 16, 64), presense of the target (present, absent) and the third factor with two levels (C, F). After that I ran a repeated ...
1
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1answer
36 views

How to report data when there is interaction

I did a multivariable logistic regression analysis to estimate the effect of an exposure (E) on an outcome while adjusting for confounders. I investigated interaction and discovered a significant ...
0
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1answer
55 views

How to explain when Main Effect and Interaction are not significant?

I've spent hours trying to interpret my data but I can't figure out how to explain the results when both the main effect and the interaction are not significant. I'm suppose to discuss my results, ...
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0answers
11 views

Testing for a 3-way interaction between a within-subjects factor, a continuous IV and a categorical IV in SPSS

I'd like to test whether the moderating effect of a (continuous) personality variable on the effect of an experimental manipulation differs between conditions. Does anyone know how to go about this in ...
1
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1answer
43 views

R adds unexpected variable to interaction model

Not sure if this is more of a programming question (in which case please move to stack overflow) or a statistical model question (in which case, please read on!) I'm exploring a data set and doing ...
2
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1answer
39 views

Interaction effect of 2x2 ANOVA in meta-analysis

I want to meta-analyze the interaction effect of a 2x2 ANOVA. (I am not talking about an interaction in the meta-regression, as in this question but about an interaction as the focal effect that ...
0
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1answer
29 views

Dropping the interaction term when the interaction effect is not significant?

Can I drop the interaction term from the model if the interaction term is insignificant?
0
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1answer
15 views

main effects of moderating variables

I am sorry if this is very trivial and a repetition. I could not find a direct question on the website that addresses my question I am studying the relationship between X1 (independent variable) and ...
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0answers
27 views

Can I interpret a simple slope if the product is not significant?

I used Hayes' PROCESS macro to run a simple regression. The interaction product was not significant (p=0.13) however the conditional effect (simple slope) was significant (at high levels of the ...
2
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1answer
55 views

Investigating interaction

Please I need to check for interaction before building an explanatory model (logistic regression). I have 16 interaction terms in total. Please how what is the best way to go about it. Will I need to ...
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3answers
73 views

Testing and reporting interactions in multiple regression

I have a model with two between-participants predictors -- one continuous (a), and one categorical with two levels (b) -- and ...
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2answers
102 views

How should I model interactions between explanatory variables when one of them may have quadratic and cubic terms?

I'm sincerely hoping that I have phrased this question in such a way that it can be definitively answered--if not, please let me know and I will try again! I should also I guess note that I will be ...
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0answers
50 views

Interaction with contrast and dummy coding

I have a question regarding the interpretation of an interaction using categorical variables where one is dummy coded (0, 1) and the other is contrast coded. The variables are: Var1: 3 levels, ...
0
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1answer
41 views

regarding the explanation of interaction plot

I was trying to draw an interaction plot for two predictor variables as follows: interaction.plot(xtest[,2],xtest[,8],y) I got the following plot. I do not know ...
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1answer
33 views

Interpretation of significant interaction

I look for an intuitive understanding of interaction effect in ANOVA or regression. Let's keep things simple as the following. Suppose we have a standard 2 x 2 factorial design, where each factor ...
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70 views

testing interaction terms in regression model [duplicate]

Based on domain knowledge and preliminary variable selection, we have decided a set of 10 variables as predictor variables for building regression models. What are the general approaches to identify ...