Dear Ladies and Gentlemen,
I am new to the Mailing list and have a question concerning
the ordered logistic regression command polr in the mass library:
My script imports data from an Excel file and stores
it in a variable called “Dataset”:
Dataset <- importData(“file.xls”,
startCol = 1, pageNumber = 4, type = "EXCEL")
The formulas for the ordered logistic regression are
stored in an array:
modelformula <- c("formula1”,”formula2”,…)
The script runs through a for loop and calculates one
formula in the array after the other. The coefficients, errors and t-values of
each calculation are supposed to be stored in a row of the two dimensional
array “results”:
for (count in 1:length(modelformula)){
mod<-polr(formula = modelformula[count],
data="" na.action = "">
results[count,5:7]<-coefficients(summary(mod))[1,1:3]
}
For the first iteration the array “results”
contains the correct results. However, for the second and all further
iterations only the coefficients stored in “results” seam correct, and
the standard errors and t-values are not. In fact they are quite similar to the
standard errors and t-values from the first iteration.
Does somebody know why I do not get the correct
standard errors and t-values as from the second iteration? Is this a bug in
S-Plus or do I have to resolve an issue with Pointers?
Best regards,
Markus Haverkamp
S-Plus version: S-PLUS®
7.0 for Windows PROFESSIONAL DEVELOPER
Windows version: Microsoft Windows XP Professional
Version 2002 Service Pack 2
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