Questions tagged [main-effects]
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25 questions
1 vote
1 answer
124 views
How to retrieve main group effects from GEE in R (anova?)
I want to know if the outcome variable differs across three groups. As my data includes several family members, I use a Generalized estimating equations (GEE) model in R: ...
- 13
4 votes
2 answers
217 views
How do I work out the significance of main effects in negative binomial models with more than two factors?
I am trying to look at how the number of events X is affected by the three factors A (4 levels), B (2 levels) and C (2 levels) using a negative binomial model as follows: ...
- 481
4 votes
1 answer
122 views
6 votes
1 answer
557 views
Hierarchy principle: who defined it first?
Different questions here deal with the problem of whether to include main effects in interaction models, for example here, here and here (for the opposite problem, omitting interaction coefficients ...
- 3,403
3 votes
1 answer
292 views
Interaction term switching sign of main effect
I'm estimating the simple model communication_share ~ grid_size * n_procs. From the theoretical background I would expect a negative effect of grid size and a ...
- 33
0 votes
0 answers
92 views
Include additional main effect if confounded with main effect of interest?
We tested the preference of animals for two treatments (A/B), with the prediction that the animals would spend a different amount time receiving each treatment. The treatments were applied by two ...
- 13
1 vote
1 answer
151 views
Which is the correct way to deal with insignificant main effect of Group condition? Stick with interaction effect in RM-Anova or perform ANCOVA?
I wanted to ask conceptual about what to do with main effects? Assume, I have randomly assigned equal two groups(let's say CBT, Control; N1=25; N2:25). I collected the depression levels at three time ...
- 11
1 vote
0 answers
204 views
Center variables PROCESS Moderation model SPSS
I'm currently researching an moderation model in SPSS with Gender as Moderator. When I'm running PROCESS number 1 (moderation) I choose the option “only continuous variables that define products”. ...
- 11
0 votes
1 answer
706 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 ...
- 195
2 votes
1 answer
301 views
Main effects and interaction effects - direction?
just a quick question regarding main effects and interaction effects: For example, in a LME model like ...
- 51
0 votes
0 answers
110 views
Linear regression: interpreting main effect in the presence of an interaction with a continuous variable
I have a classical multiple regression model: $y=b_0+b_1x_1+b_2x_2+b_3x_1x_2$ where $x_1$ is binary and $x_2$ is continuous and mean-centered. My question is about the interpretation of the estimate $...
- 519
1 vote
1 answer
91 views
How to report coefficients for main effects?
Suppose I run an OLS regression as follows: Y = γ1 + γ2*X + γ3*(D*X) where D is a dummy variable. I excluded one dummy variable, so the effect is in γ2 and γ3 must ...
- 345
1 vote
1 answer
478 views
Anova shows a main effect but not the t-test
I run an ANOVA which indicates that a variable is significant, but running a t-test on the same variable shows no significance. Is this a consistent result ? Here are more details of what I did: My ...
- 11
0 votes
2 answers
140 views
Can a main effect coupled with an interaction, answer my question?
I am currently carrying out a research where I have two categorical predictors with two levels each. The research basically consists of presenting participants with one of four profiles of a target, ...
- 21
2 votes
1 answer
603 views
How to interpret an interaction in a negative binomial?
I'm investigating the influence of top management team nationality diversity (TMTdiv, continuous between 0-1) and board nationality diversity (Boarddiv, continuous between 0-1) on firm ...
- 585