I get
worms.glm <- glm(cbind(deaths, (20-deaths)) ~ sex+ doselin,
+ data=worms, family=binomial)
> attr(worms.glm, "dataClasses")
NULL
But maybe the result from somewhere within predict.lm() or model.frame()
is different.
Surely the levels attribute has no relevance to glm's c
Stripping attributes from a column in model.frame would be highly
undesirable.
The mistake was using 'unclass' when the intention was to remove the
levels (I presume). The new variable given is correctly reported as not
matching that used during fitting.
Uuse of traceback() would have shown t
