contrasts(x) contrasts(x) <- ctr
x
| a factor. |
ctr
|
either a matrix whose columns give coefficients
for contrasts in the levels of x , or the (quoted)
name of a function which computes such matrices.
|
options("contrasts")
are used.contr.helmert
,contr.poly
,
contr.sum
,contr.treatment
,
glm
,lm
.