Dear R-help list,
I'm attempting to use the ROC routine from the epicalc package after
performing a logistic regression analysis. My code is included after
the sessionInfo() result. The datafile (GasketMelt1.csv) is attached.
I updated both R and the epicalc packages and tried again before
sending this request.
sessionInfo result:
R version 2.9.1 (2009-06-26)
i386-pc-mingw32
locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
States.1252;LC_MONETARY=English_United
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
attached base packages:
[1] splines stats graphics grDevices utils datasets methods
[8] base
other attached packages:
[1] caret_4.19 lattice_0.17-25 epicalc_2.9.1.2 survival_2.35-4
[5] foreign_0.8-36
loaded via a namespace (and not attached):
[1] grid_2.9.1 tools_2.9.1
Header information from package 'epicalc':
Package: epicalc
Version: 2.9.1.2
Date: 2009-07-14
My code ...
#------------------------------------------------
# Logistic Regression (the model result is as expected)
#------------------------------------------------
dfile = 'GasketMelt1.csv'
gmelt.df = read.csv(dfile, header = TRUE, as.is = TRUE)
names(gmelt.df)
gmelt.df$p = gmelt.df$Pass / gmelt.df$Total
gmelt.glm = glm(p ~ Time + Temperature + Depth
+ Time*Temperature + Time*Depth + Temperature*Depth,
family = binomial(link = logit), data=gmelt.df,
weight=Total)
summary(gmelt.glm)
#------------------------------------------------
# ROC
#------------------------------------------------
library(epicalc)
lroc(gmelt.glm, graph = TRUE, line.col = "red")
The error message:
> lroc(gmelt.glm, graph = TRUE, line.col = "red")
Error in dimnames(x) <- dn :
length of 'dimnames' [2] not equal to array extent
Have I overlooked something?
Many thanks to anyone who might have a suggestion.
Cliff
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