David,
I am sorry, I did not read your question as `why dummy coding not poly
coding', but I still seemed to have answered it. BTW,
contr.poly(a, contrasts = FALSE)
should be an indicator matrix according to its help page, so I would not
have expected what you expected, and if it had be
Brian, many thanks for these helpful pointers:
On 23 Feb 2005, at 15:45, Prof Brian Ripley wrote:
MASS4 p.150
White Book p.38
Those are the only two reasonably comprehensive accounts that I am
aware of (and they have only partial overlap).
The underlying motivation is to span the _additional_ vec
MASS4 p.150
White Book p.38
Those are the only two reasonably comprehensive accounts that I am aware
of (and they have only partial overlap).
The underlying motivation is to span the _additional_ vector space covered
by the term, the complement to what has gone before. Put another way, as
each
