Regressionsanalyse - NA as coefficients

[steffi]

Hey i have a problem with my regression analysis
I have 4 Treatment Groups, thus I've tried to build Dummy Variables for those. Then I wanted to put those dummies in the Regression as dependent Variables. I used the Trigger of my Survey to build those new Variables by recoding them ...

The problem is that I only get NA's as coefficients, which is super frustrating cause I don't find the problem

Dummy- Variablen für die Treatment - Gruppen erstellen, um eine Regression zu erstellen

Treatement 1

Rohdaten_xlsx$DT1 <- recode(Rohdaten_xlsx$c_0001,"1=1;2:4=0")
Rohdaten_xlsx$DT1

#Treatment 2
Rohdaten_xlsx$DT2 <- recode(Rohdaten_xlsx$c_0001,"2=1;1=0; 3:4=0")
Rohdaten_xlsx$DT2

#Treatement 3
Rohdaten_xlsx$DT3 <- recode(Rohdaten_xlsx$c_0001,"3=1;1:2=0;4=0")
Rohdaten_xlsx$DT3

#Treatement 4
Rohdaten_xlsx$DT4 <- recode(Rohdaten_xlsx$c_0001,"4=1;1:3=0")
Rohdaten_xlsx$DT4

#Regression mit Dummies --> Problem nur NA Werte
Model_Preise_2<- lm(Rohdaten_xlsx$KB_T1~ Rohdaten_xlsx$DHP1n+ Rohdaten_xlsx$DHG1n +Rohdaten_xlsx$DT1+ Rohdaten_xlsx$DT2+Rohdaten_xlsx$DT3)
summary(Model_Preise)

My professor said I Also can use as.factor in my regression, because this would build the dummies
-> I just don't know how to use these

Thanks for your help

[jrkrideau]

FAQ: How to do a minimal reproducible example ( reprex ) for beginners

A minimal reproducible example consists of the following items: A minimal dataset, necessary to reproduce the issue The minimal runnable code necessary to reproduce the issue, which can be run on the given dataset, and including the necessary information on the used packages. Let's quickly go over each one of these with examples: Minimal Dataset (Sample Data) You need to provide a data frame that is small enough to be (reasonably) pasted on a post, but big enough to reproduce your issue. Let's say, as an example, that you are working with the iris data frame head(iris) #> Sepal.Length Sepal.Width Petal.Length Petal.Width Species #> 1 5.1 3.5 1.4 0.…

@steffi

I have 4 Treatment Groups, thus I've tried to build Dummy Variables for those.

If I recall correctly, regression analysis in R constructs dummy variables automatically so one does not create them manually as one used to do in SAS or SPSS.