All Questions
38 questions
1
vote
2
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57
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How do I interpret different results from simple regression, multiple regression, moderation, and mediation?
I'm currently doing a multiple linear regression analysis on Spirituality and Forgiveness to see how it affects Life Satisfaction.
If I put the IVs individually into linear regression they both show ...
- 11
6
votes
3
answers
608
views
Is it meaningful to test the interaction effect if there is no significant effect in the main effect model?
Suppose we have a linear regression model with two covariates, $y = \beta_0 + \beta_1 x_1 + \beta_2 x_2$.
There are three possible scenarios:
Both $\beta_1$ and $\beta_2$ are significant.
Either $\...
- 347
3
votes
3
answers
490
views
Comparing models with main effects and interactions
I have two models:
Model 1: Only contains independent variable $x$, while $x$ is non-significant.
Model 2: Contains $x$, $m$, and $x * m$, and $x * m$ is significant.
How could I illustrate this ...
- 31
1
vote
0
answers
71
views
Fixed effects regression for unbalanced panel data (sample size, interaction term, statistical significance)
I have a highly unbalanced panel data set (n= 70 firms, T= 5-3000 observations per firm, N= 15000 observations overall). I specified a fixed effect regression with time and entity fixed effects. I ...
- 31
1
vote
2
answers
107
views
When is an interaction in quadratic regression significant?
I run a regression with a continuous variable $x_2$ and a binary grouping variable $x_1$. We suppose that the effect of $x_2$ is quadratic on the dependent variable $y$ and our question is whether the ...
- 343
0
votes
1
answer
134
views
Test for moderation effect in multiple regression
I am trying to build a regression model to find the correlation between the features of thumbnails and the popularity of videos. I am proposing that category of videos is the moderator of the ...
- 1
0
votes
1
answer
589
views
One of the main effects not significant, but interaction term significant
A is significant
B is not significant
A x B is significant
Do I say that
(1) There exists a ...
- 165
1
vote
1
answer
384
views
Compare conditional effects (simple slope) from regression model
I have the following regression outputs from a model that includes both quadratic and cubic interaction terms. I calculated the simple slopes using the simle_slope from reghelper.
...
- 347
0
votes
0
answers
148
views
How to test interaction effect with small sample size?
Into my model x is categorical variable with 3 categories: 0,1 & 2, where 0 is reference category. However number of "0" categories are much larger than others (1,2) which increases the ...
- 111
1
vote
2
answers
73
views
Testing whether dividing independent variable into groups is rational
Let's imagine that we have three variables - $Y, X_1$ and $X_2$, where $Y$ is dependent continuous variable, $X_1$ is continuous variable and $X_2$ is discrete variable with two factors - $0$ and $1$. ...
- 532
1
vote
1
answer
78
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Exploring shifts in response to dichotomous dependent variable
I have one dichotomous dependent variable (buried with grave goods or not) and a series of categorical and continuous independent variables (age at death, year of death, sex, socioeconomic status) for ...
- 13
2
votes
3
answers
94
views
Why main effect becomes non-significant after reversing moderator?
I am currently fitting a linear regression with two IVs and their interaction effect:
Y = β1X1 + β2X2 + β3X1*X2
The data was collected in an experimental study.
X1 is a dummy variable, taking the ...
- 23
0
votes
1
answer
91
views
Help: Interpretation of Interaction Effect using a Linear regression in R
Im applying a regression to test the association between maternal postpardum depression score (maternal_postpardum_score) and functional connectivity changes (FC) in the brain - both continuous. I ...
- 147
2
votes
1
answer
294
views
Regression - Merging separate linear regression models
I'm trying to assess if the following intuition has sense or not. Any help will be appreciated.
Consider two simple linear models obtained in the same experimental framework (for example, measurements ...
- 472
1
vote
2
answers
71
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Linear regression for main effect not interaction effect
I have a linear equation:
lm(Connectivity ~ (Complex-Attention + Memory)*MDD, data = D)
From this association I obtain a significant main effect but no ...
- 23
6
votes
2
answers
8k
views
How do you get confidence intervals for interactions of variables?
Suppose I am building an OLS model with the following specification:
$$y = \alpha + \beta_0x_0 + \beta_1x_1 + \beta_2x_0x_1 + \epsilon$$
The variable $x_1$ is continuous and $x_0$ is binary. When $x_0$...
- 2,251
6
votes
1
answer
297
views
Does a significant interaction necessarily implies that at least one of the simple effects will be significant?
Considering that the interaction between two variables is significant, is it always the case that at least one of the two simple effects will be significant? If so, is there any proof or a counter ...
- 613
-1
votes
1
answer
544
views
How to determine economic significance of an interaction term of two continuous variables in an OLS regression? [closed]
Y= Intercept+ Beta1X1+ Beta2X2+ Beta3(X1X2)**
I want to determine the economic significance of Beta3 when Y, X1, and X2 are continuous variables, preferably in terms of standard deviation units. Is ...
1
vote
2
answers
196
views
Statistical illusion? What's statistically happening, when regression analysis results get significant only with all predictors and interaction term?
I got a research question, where the hypothesis (derived from theory) postulates, that the relationship between predictor X and outcome Y is moderated by W (X+W+X*W -> Y). All variables are sums of ...
- 247
0
votes
1
answer
157
views
Regression interaction terms in stata
I am currently studying the relationship between having a supervisory job and having traditional values when it comes to child care (woman staying home). I want to find the relationship with ...
- 35
2
votes
1
answer
2k
views
Interaction term is significant WITHOUT main affects... AND main effects are significant WITHOUT interaction term?
I am trying to determine the effect of a person's weight and the incline that they are running over on their running speed. I'm just using a simple linear model in R, but I get a weird situation where ...
- 63
0
votes
0
answers
91
views
how to interpret if the coefficients of two predictors are positive,the coefficient of the interaction term is negative? [duplicate]
I have a multiple regression model.The predictors A,B,AB are all significant. But the coefficients of A and B are positive while the coefficient of AB is negative. How to interpret it?
(A ranges from -...
- 1
3
votes
1
answer
12k
views
How to test if an interaction is significant: interaction terms or model comparison?
I ask the question based on a current case, but I would really appreciate a general answer, because it has been bugging me for some time:
I'm running regressions with interaction effects.
How do I ...
- 33
2
votes
1
answer
250
views
Ceiling effect in mediation AND/OR moderation
I have a variable (Y) with a mean that is probably too high. (and large prop of participants scoring the maximum score)
My hypothesis was that X-Y is stronger at high (vs. low) levels of the ...
- 381
1
vote
1
answer
369
views
Interpreting insignificant 3 way-interaction alongside significant 2-way interaction
Let's say we have a situation like this - we are predicting y with one continuous (cont) and 2 categorical predictors (A and B). A and B have only two levels - 1 and 0, and reference is 0
$y\sim cont+...
- 1,782
5
votes
1
answer
1k
views
Significance in simple regression but not multiple regression
Background: I am trying to show an increase in a number of variables over time, so initially I ran a simple linear regression. However, I subsetted the data so ...
- 427
0
votes
2
answers
1k
views
Moderator and Independent variable Interaction terms non-significant
I have fitted a regression model on my mean-centered variables. Every regression coefficient is significantly different from zero but the interaction terms created by multiplying the independent ...
- 445
4
votes
3
answers
9k
views
Significant interaction but non-significant simple slopes
I conducted a multiple regression analyses that included an interaction term (continuous x continuous). The interaction term was significant, but none of the simple slopes (1 SD above the mean, at the ...
1
vote
1
answer
3k
views
Logistic regression: my main effects lose significance when I add my interaction effects. Why?
I have a dichotomous dependent variable for a 2x3 experiment. There are about 30 observations in each cell, for a total sample size of about 180. Each person was only in one cell. The dependent ...
- 13
5
votes
1
answer
3k
views
Adjusted R-squared: number of terms or independent variables?
When applying a multiple linear regression, does the adjusted R-squared value depend on the number of independent variables in the model or the number of terms? Specifically, I'm concerned that adding ...
- 921
1
vote
0
answers
61
views
interaction term not in expected direction [closed]
I am conducting a hierarchical regression analysis to test interaction effects. The main variable and the moderator are related to the dependent variable significantly and in expected direction.
...
- 11
5
votes
0
answers
5k
views
How to determine the significance of an interaction?
My question is simple:
How do you determine the overall significance of an interaction (i.e. the marginal effect of $X$ on $Y$ for different values of $Z$)?
But the background is a bit long-winded,...
- 1,133
13
votes
1
answer
53k
views
The main effect will be non-significant if the interaction is significant? [duplicate]
I am using linear mixed models to identify important factors, and it turns out that:
A: significant
B: not significant
...
- 1,345
4
votes
1
answer
3k
views
Interpretation of interaction terms if main effect is insignificant
I have read the questions posted here about how to deal with the situation of significant interaction terms but insignificant 'main' effects, and my main take-away is that it depends on your research ...
- 563
2
votes
1
answer
288
views
Comparison of two linear regression models with squared regressors
I need to compare two linear regression models that include the regressors in levels and in squares:
$Y=a_1x^2+b_1x+c_1$ and $Y=a_2x^2+b_2x+c_2 $
Specifically, I need to test whether these ...
- 21
0
votes
0
answers
117
views
How to address and acknowledge a significant interaction that has little practical meaning
I am building a model with a highly significant interaction. This interaction was one of our main hypotheses. It is clear, however, that the form that the interaction takes does not represent a ...
- 187
7
votes
1
answer
7k
views
How to interpret the significant interaction of two non-significant main predictors?
I have two non-significant main binary variables in my binary logistic regression model, but their interaction is significant. The variables are centered and no multicollinearity is the case (all VIFs ...
- 1,363
3
votes
2
answers
525
views
Graphing versus further testing interactions
Following the question here, I have come across different (textbook) recommendations.
Some authors suggest that the effect of the moderating variable is best understood in a graphic form.
Others ...
- 3,345