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Missing predictor variable in GLMM.nb outcome

After running the model: ...
Adrianna Elihu's user avatar
4 votes
2 answers
102 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: ...
Insect_biologist's user avatar
4 votes
1 answer
60 views

2x2 design (ANOVA): can i only look a 1 main effect and an interaction?

I have a model: ...
DS14's user avatar
  • 105
6 votes
1 answer
236 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 ...
robertspierre's user avatar
3 votes
1 answer
169 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 ...
tadeseus's user avatar
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0 answers
56 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 ...
bos's user avatar
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1 vote
1 answer
62 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 ...
Connor's user avatar
  • 11
1 vote
0 answers
98 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”. ...
Daan's user avatar
  • 11
0 votes
1 answer
487 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 ...
nerd's user avatar
  • 165
2 votes
1 answer
195 views

Main effects and interaction effects - direction?

just a quick question regarding main effects and interaction effects: For example, in a LME model like ...
Zucchini's user avatar
0 votes
0 answers
71 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 $...
monade's user avatar
  • 519
1 vote
1 answer
44 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 ...
TFT's user avatar
  • 345
1 vote
1 answer
340 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 ...
celia's user avatar
  • 11
0 votes
2 answers
58 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, ...
ERMM's user avatar
  • 21
1 vote
1 answer
396 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 ...
Charlie Glez's user avatar
0 votes
0 answers
203 views

Why type III sum of squares is not recommended to use when there is significant interaction?

I did notice that in the following example, I obtained a insignificant main effect for treatment when including interaction, although the treatment is clearly effective. Any intuitive explanation? ...
hehe's user avatar
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1 answer
253 views

Factor Levels in a Two-Way ANOVA

I'm trying to figure out the explanations of the Effect Plots below. I believe I have figures out Figure 9a, but the explanation for Figures b, c, and d given in the textbook I do not comprehend. Any ...
Chesso's user avatar
  • 423
3 votes
1 answer
3k views

Main effect vs simple effect

In the following linear model: $y = \beta_0 +\beta_1 x_1 +\beta_2 x_2 + \beta_3x_1x_2 + \epsilon$ what are called $x_i$? The term $x_1x_2$ is the interaction. In ANOVA, $x_i$ are named "main ...
POC's user avatar
  • 668
0 votes
1 answer
282 views

Using Orthogonal Main Effects Plan to select profiles for conjoint analysis

I am trying to create a code in Python to select orthogonal profiles given some attributes and levels. For eg: ...
DS_1's user avatar
  • 1
0 votes
1 answer
2k views

Three-way MANOVA Interpretation

I'm interpreting a three-way MANOVA as part of my research, and have come across an interpretation challenge, with three independent variables (Factor A, Factor B, and Factor C) and two dependent ...
Neszka's user avatar
  • 1
2 votes
1 answer
3k views

Why are Simple Effects only used when the interaction is significant?

I have conducted a 2-way ANOVA and obtained a significant Main Effect in IV1 and IV2, but a non-significant interaction. Following that, I have analyzed IV1 using a test for Simple Effects and ...
Hecealdor's user avatar
2 votes
1 answer
854 views

lmer Dropping levels from summary information in models with main effect and interactions

First off, here are my models: ...
UnsoughtNine's user avatar
1 vote
0 answers
82 views

Interaction effect in logistic regression

I have applied logit model, where my dependent variable is Emp (Employment) 1 if employed otherwise 0, and used level of education and Health status as independent variables where: Education consist 6 ...
Salim Khan's user avatar
0 votes
0 answers
496 views

How to handle interaction in this longitudinal model?

Let's assume we have the following result of a longitudinal experiment, which evaluates the effect of a fertilizer over time. The dependent variable is about "poor condition". The higher ...
GibbsSampler10's user avatar
2 votes
1 answer
352 views

Interpreting growth curve analysis (GCA) main effect in light of interaction (eye tracking data)

I have fit parabolas to two groups in a growth curve analysis (GCA) of eye tracking data using orthogonal polynomials (essentially by following Dan Mirman's example for his paper with Magnuson in 2009,...
Meg's user avatar
  • 1,863