Hi,
I have a dataset that I am trying to analyze and plot as an ordered logistic
regression (y = ordinal categories 1-3, x = continuous variable with values
3-9).
First is a problem with cdplot:
Produces a beautiful plot, with the "right" trend, but my independent factor
values are transformed. The factor has values from 3-9, but the plot
produces an x-axis with values from 20-140. When I force the xlim to be
3-9, it produces a plot without the trend, which can't be correct.
Second is a problem with polr:
The output of the summary command of the model built with polr includes t
values for lots (if not all) of my independent factor values, but does not
produce a summary of the fit of the model or of the overall fit of the
factor. Also, intercepts are different from those produced with a logistic
fit in JMP...
Code below, any help much appreciated.
Thanks
Beth
LogAntDensityFactor<-as.factor(LogAntDensity)
###order ordinal variable
HammerCatOrd<-ordered(HammerCat)
###set ordered ordinal dependent variable as factor
HammerCatOrdFactor<-as.factor(HammerCatOrd)
###density plot with three levels
cdplot(HammerCatOrdFactor~LogAntDensityFactor,xlab="Log(Ant
Density)",ylab="Latency
of response to disturbance (1-3)")
require(MASS)
logordered<-polr(HammerCatOrdFactor~LogAntDensityFactor,Hess=TRUE)
summary(logordered,digits=3)
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