rocsurf.trin {trinROC} | R Documentation |
Trinormal ROC surface plot
Description
Function for computation of the trinormal ROC surface.
Usage
rocsurf.trin(x, y, z, p = 300, plot = TRUE, saveVUS = FALSE)
Arguments
x , y , z |
Vectors containing the data of the three classes "healthy", "intermediate" and "diseased". |
p |
An integer for the precision of the surface. |
plot |
logical. If TRUE (default), the VUS is plotted using |
saveVUS |
A logical whether to save a PNG of the VUS in your current
working directory (default is |
Details
This function takes three-class ROC data and computes the three
dimentional surface using the R-package rgl
. The ROC surface is
defined as
where are the two cut-off points and
the
cdf of the three classes with
.
Value
A list with the following components:
t1 , t2 |
The vectors |
zVUS |
The matix containing the surface values. |
x , y , z |
The original data. |
References
Xiong, C., G. Van Belle, et al. (2006). Measuring and estimating diagnostic accuracy when there are three ordinal diagnostic groups. Statistics in Medicine 25(7), 1251–1273.
Examples
data(cancer)
x1 <- with(cancer, cancer[trueClass=="healthy", 8])
y1 <- with(cancer, cancer[trueClass=="intermediate", 8])
z1 <- with(cancer, cancer[trueClass=="diseased", 8])
rocsurf.trin(x1, y1, z1)