pcX {eba} | R Documentation |
Computes a paired-comparison design matrix.
pcX(nstimuli)
nstimuli |
number of stimuli in the paired-comparison design |
The design matrix can be used when fitting a Bradley-Terry-Luce (BTL)
model by means of glm
.
A matrix having (nstimuli-1)*nstimuli/2
rows and
nstimuli
columns.
data(celebrities) # absolute choice frequencies btl <- OptiPt(celebrities) summary(btl) btl.glm <- glm(cbind(btl$y1, btl$y0) ~ pcX(9)[,-1] - 1, binomial) summary(btl.glm) # BTL model does not fit these data!