I fit a proportional odds model
with the polr-function of the MASS package from
Venables and Ripley 
 

Applying the confint method to  calculate confidence intervals for the
parameters I get 
the following error message
 

Waiting for profiling to be done...
Re-fitting to get Hessian
Error in X[, -i, drop = FALSE] : incorrect number of dimensions
 
Can someone explain the error-message?
 
(The data are from McCullagh (1980), JRSS,B)
 
 

tonsiles<-data.frame(carrier=factor(rep(c('yes','no'),each=3)),
                     size=ordered(rep(c(1,2,3),2)),
                     count=c(19,29,24,497,560,269))
library(MASS)
m<-polr(size~carrier,data=tonsiles,weights=count)
 confint(m)
 

Ulrich
 

platform       i386-pc-mingw32           
arch           i386                      
os             mingw32                   
system         i386, mingw32             
status                                   
major          2                         
minor          3.0                       
year           2006                      
month          04                        
day            24                        
svn rev        37909                     
language       R                         
version.string Version 2.3.0 (2006-04-24)
 

Ulrich Halekoh
Danish Institute of Agricultural Sciences
Unit of Statistics and Decision Analysis
Denmark
 

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