R help - Apr 2009 - How to handle tabular form data in lmer without expanding the data into binary outcome form?

Dear R-gurus:

I have a question about lmer.
Basically, I have a dataset, in which each observation records number of
trials (N) and number of events (Y) given a covariate combination(X) and
group id (grp_id).
So, my dataset is in tabular form. (in case my explanation of tabular form
is unclear,
please see the link:
http://www.stat.psu.edu/online/development/stat504/06_logreg/11_logreg_fitmodel.htm
)

My question: what is the lmer syntax for tabular data ("model Y/N=X"
is the
what SAS does as seen in the link above).
In specific, where can I add N (number of trials) into the following line of
lmer code?
m1 <- lmer(Y ~ X+(1|grp_id), family=biomial(link="logit"))
As you may expect, I try to avoid expanding the tabular form data into
binary (0,1) outcome form data because doing so causes a quite large data
matrix in my study).
A link with similar question is seen at
https://stat.ethz.ch/pipermail/r-help/2008-May/161072.html
Seems to me, that link is implementing data expansion approach (they have
only 1600 obs after data expansion).
If someone knows a neat solution other than data expansion, please help.

Many thanks in advance!

-Sean

	[[alternative HTML version deleted]]

See ?lmer and notice model gm1 in the examples.

As with glm, a binomial lmer model can have the response specified "as
a two-column matrix with the columns giving the numbers of successes
and failures".

hth,
Kingsford Jones

On Fri, Apr 10, 2009 at 2:48 PM, Sean Zhang <seanecon at gmail.com>
wrote:
> Dear R-gurus:
>
> I have a question about lmer.
> Basically, I have a dataset, in which each observation records number of
> trials (N) and number of events (Y) given a covariate combination(X) and
> group id (grp_id).
> So, my dataset is in tabular form. (in case my explanation of tabular form
> is unclear,
> please see the link:
>
http://www.stat.psu.edu/online/development/stat504/06_logreg/11_logreg_fitmodel.htm
> )
>
> My question: what is the lmer syntax for tabular data ("model
Y/N=X" is the
> what SAS does as seen in the link above).
> In specific, where can I add N (number of trials) into the following line
of
> lmer code?
> m1 <- lmer(Y ~ X+(1|grp_id), family=biomial(link="logit"))
> As you may expect, I try to avoid expanding the tabular form data into
> binary (0,1) outcome form data because doing so causes a quite large data
> matrix in my study).
> A link with similar question is seen at
> https://stat.ethz.ch/pipermail/r-help/2008-May/161072.html
> Seems to me, that link is implementing data expansion approach (they have
> only 1600 obs after data expansion).
> If someone knows a neat solution other than data expansion, please help.
>
> Many thanks in advance!
>
> -Sean
>
> ? ? ? ?[[alternative HTML version deleted]]
>
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