contr.SAS(n, contrasts=TRUE)
n
rows and k
columns, with k=n-1
if
contrasts
is TRUE
and k=n
if contrasts
is
FALSE
.n
levels. The returned value contains the
computed contrasts. If the argument contrasts
is FALSE
then a square indicator matrix is returned. These contrasts are similar to those from contr.treatment
except that they represent shifts relative to the last level of the
factor, not the first level. This generates the same parameterization for a
linear model as is used in SAS (see
contr.treatment