help on retrieving output from by( ) for regression

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