Skip to main content

All Questions

Filter by
Sorted by
Tagged with
5 votes
2 answers
109 views

How to calculate the reference level interaction in regression in R?

I am very confused on calculating the reference level interaction in regression in R. Here is the sample code: ...
3 votes
2 answers
1k views

Which groups are reference groups in a regression model with interaction?

What are the reference groups in a regression model where there are interaction categories? Using the iris dataset in R, I've created a category with three levels ...
0 votes
1 answer
68 views

Are these effects missing from my glm output because of a possible dummy trap?

I have a few generalized linear mixed model questions. I have an experiment that asked "is there a differential response between asexuals and sexuals by population density?". I am ...
1 vote
1 answer
2k views

Interaction effects in regression models - should I include reference category?

I have a question about coding interaction effects using dummy coding which I’d be really grateful for your advice on please. Imagine I want to design an experiment to measure the impact of amount of ...
3 votes
1 answer
909 views

Interpreting the effects of dummy interactions

Warning This question is quite long, and maybe a lot of you will think it is too long. I however thought, and hope, that if this question gets a proper answer, it will actually be a really good post ...
1 vote
0 answers
368 views

Panel Data Regression in R with Dummy Variables [closed]

I am currently working on my thesis and thereby analyzing the effects of the increase of COVID-19 cases on the main stock indices of the G7 countries. For this purpose, I have divided the whole period ...
4 votes
2 answers
183 views

Variable for logistic regression is categorical and continuous so creates “missingness” in R

I am doing a logistic regression analysis using the glm command in R. It is to identify causes of valve narrowing beyond a certain threshold; 0=no narrowing, 1=narrowed. One of my variables is the ...
0 votes
0 answers
33 views

Assess impact on results of participants recruited via additional outreach efforts

I am currently working on a project that evaluates certain study recruitment strategies in regards of increasing participation among different subgroups. One of those strategies is reminder letters. ...
0 votes
1 answer
2k views

Interaction term with several levels in multi linear regression in R [closed]

first of all thank you very much for admitting me! I am currently stuck with a problem regarding interaction terms: I would like to interact a categorical variable with several levels with a ...
2 votes
1 answer
2k views

Simple effects of categorical interaction

I have two two-level categorical variables, IV1 and IV2. I want to fit a linear model in R and find out the simple effect of IV1 on the DV at each level of IV2, separately. I'm not interested in the ...