On Feb 12, 2011, at 11:16 AM, Ista Zahn wrote:
Well, I may have been too hasty there. Actually the question was
slightly improved. I think you are looking for ?contr.sum
Another issue will arise besides what the switch of the contrasts
-- The intercept is not a "general effect" but rather a combined
intercept for all of the continuous terms estimated when they are
simultaneous zero. (Only in the situation where the continuous
variables had all been centered would this be anywhere near the
"general effect" or "grand mean". ) I infer that OP has been brought
up in an anova tradition and has not made a proper transition to
regression.
Perhaps what could be explored is whether the predict() function is a
path to enlightenment or at least partial satisfaction.
?predict
OP: Try something along these lines with the names for the factor
variables matching that of the original data and choosing a
representative value or values for the continuous variables:
predict(mdl, data.frame(lev1=factor(val1,val2,val3, levels=levels(dat
$lev1)),
lev2= ... etc
etc=etc ), contin=median(dat$contin) )
)
Perhaps with expand.grid() if combinations are needed.
--
david. .... er, David.
Best,
Ista
On Sat, Feb 12, 2011 at 3:55 PM, Ista Zahn
<iz...@psych.rochester.edu> wrote:
I already responded to your identical post yesterday, asking you to
actually ask a question. "can you please help me?" is not enough.
Best,
Ista
On Sat, Feb 12, 2011 at 5:57 AM, ATANU <ata.s...@gmail.com> wrote:
i am trying to fit a linear model with both continuous covariates
and
factors. When fitted with the intercept
term the first level of the factor is treated by R as intercept
and the
estimate of the effects of remaining levels(say i th level) are
given as
true estimate of i th level - estimate of 1st level. i want the
estimates of
coefficients of each level along with the intercept term(general
effect).can anyone please help me?
thanks in advance.....
--
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http://r.789695.n4.nabble.com/linear-models-with-factors-tp3302404p3302404.html
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--
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org
--
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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