R help - May 2012 - Lattice: Add abline to Single Value qqmath() Plot

The data are not normally distributed when untransformed and I'm trying
various transformations to see if any would be appropriate to use. The
lattice book (fig. 3.10) shows a 2-sample Q-Q plot with an abline but the
code for the figure does not include the line.

   I'd appreciate a pointer to a reference on how to add an abline to a
one-sample qqmath() plot in lattice.

Rich

Take a look at section 3.3.6 qqmath
http://www.his.sunderland.ac.uk/~cs0her/Statistics/UsingLatticeGraphicsInR.h
tm

You need to create a panel function. See sections 2.5.2 and 2.5.3 in the
second chapter of the Lattice book
(http://dsarkar.fhcrc.org/lattice/book/chapter2.pdf) available on Deepayan
Sarkar's webpage.

This is a simple example modified from the example in the lattice package
manual:

qqmath(~ rnorm(100), 
  panel = function(x, ...) {
    panel.qqmathline(x, ...)
    panel.qqmath(x, ...)
  })


----------------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77843-4352
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Rich Shepard
> Sent: Tuesday, May 15, 2012 12:31 PM
> To: r-help at r-project.org
> Subject: [R] Lattice: Add abline to Single Value qqmath() Plot
> 
>    The data are not normally distributed when untransformed and I'm
> trying
> various transformations to see if any would be appropriate to use. The
> lattice book (fig. 3.10) shows a 2-sample Q-Q plot with an abline but
> the
> code for the figure does not include the line.
> 
>    I'd appreciate a pointer to a reference on how to add an abline to a
> one-sample qqmath() plot in lattice.
> 
> Rich
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-
> guide.html
> and provide commented, minimal, self-contained, reproducible code.