[R] help on retrieving output from by( ) for regression
Marc Schwartz
MSchwartz at mn.rr.com
Thu Aug 25 15:44:13 CEST 2005
Also, looking at the last example in ?by would be helpful:
attach(warpbreaks)
tmp <- by(warpbreaks, tension, function(x) lm(breaks ~ wool, data = x))
# To get coefficients:
sapply(tmp, coef)
# To get residuals:
sapply(tmp, resid)
# To get the model matrix:
sapply(tmp, model.matrix)
To get the summary() output, I suspect that using:
lapply(tmp, summary)
would yield more familiar output as compared to using:
sapply(tmp, summary)
The output from the latter might require a bit more "navigation" through
the resultant matrix, depending upon how the output is to be ultimately
used.
HTH,
Marc Schwartz
On Thu, 2005-08-25 at 14:57 +0200, TEMPL Matthias wrote:
> Look more carefully at
> ?lm
> at the See Also section ...
>
> X <- rnorm(30)
> Y <- rnorm(30)
> lm(Y~X)
> summary(lm(Y~X))
>
> Best,
> Matthias
>
>
> > Hi all
> >
> > I used a function
> > > qtrregr <- by(AB, AB$qtr, function(AB) lm(AB$X~AB$Y))
> >
> > objective is to run a regression on quartery subsets in the
> > data set AB, having variables X and Y, grouped by variable qtr.
> >
> > Now i retrieved the output using qtrregr, however it only
> > showed the coefficients (intercept and B) with out
> > significant levels and residuals for each qtr. Can some on
> > help me on how can retrieve the detailed regression output.
> >
> > rgds
> >
> > snvk
> >
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