Re: [R] Error in text.rpart(fit) : fit is not a tree, just a root

[Terry Therneau]

 I've tried to make a decision tree for the following data set:

 I don't get a tree...

 The rpart routine has decided that the best model it can find is the
intercept only model, i.e., a tree with no branches at all.  Stepwise
regression can have the same outcome, by the way, if no variables pass
the F-to-enter threshold.  

The plot and text routines won't plot anything for a null tree, because
there is nothing interesting to plot.

Terry Therneau

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

[R] Error in text.rpart(fit) : fit is not a tree, just a root

[Joel Fürstenberg-Hägg]

Hi all,

 

I've tried to make a decision tree for the following data set:

 

Level X Response
279 C 2.4728646   -9.445
341 B 0.5986398   -9.413
343 B 1.1786271   -9.413
384 D 1.4797870   -9.413
390 C 2.0364569   -9.133
391 D 0.9365739   -9.133
452 A 1.2858741  -11.480
455 C 1.3256245   -9.413
510 C 0.5758865   -9.413
537 D 1.9289431   -9.413
540 C 1.8646144   -9.413
554 B 1.3903752  -10.080

 

Using these commands:

 

 fit=rpart(Response ~ X + Level, data=decTree, method=anova, 
 control=rpart.control(minsplit=1))
 
 printcp(fit) # display cp table  

Regression tree:
rpart(formula = Response ~ X + Level, data=decTree, method = anova, 
control = rpart.control(minsplit = 1))

Variables actually used in tree construction:
character(0)

Root node error: 4.4697/12 = 0.37247

n= 12 

CP nsplit rel error
1 0.01  0 1


I don't get a tree...

 

 plot(fit) # plot decision tree  
Error in plot.rpart(fit) : fit is not a tree, just a root
 text(fit) # label the decision tree plot  
Error in text.rpart(fit) : fit is not a tree, just a root

 

Can anyone tell me what's going wrong and give a hint how to solve it?

 

Best regards,

 

Joel

 

 
  
_
Nya Windows 7 - Hitta en dator som passar dig! Mer information. 
http://windows.microsoft.com/shop
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.