From: Greg Snow <Greg.Snow_at_imail.org>

Date: Thu, 18 Nov 2010 13:10:46 -0700

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. Received on Thu 18 Nov 2010 - 20:15:07 GMT

Date: Thu, 18 Nov 2010 13:10:46 -0700

Did you read the help page for qqnorm? The return value has the x and y coordinates used, you can just do something like:

> tmp <- qqnorm( resid(test.lm) )

> identify(tmp, , names(resid(test.lm)) )

Or the plot.lm function has an argument id.n that automatically labels the n most extreme values:

> plot( test.lm, 2, id.n=10 )

Those both worked in my tests, if they are not working for you then send a reproducible example (include data, see ?dput) and maybe we can help further.

--

Gregory (Greg) L. Snow Ph.D.

Statistical Data Center

Intermountain Healthcare

greg.snow_at_imail.org

801.408.8111

> -----Original Message-----

*> From: r-help-bounces_at_r-project.org [mailto:r-help-bounces_at_r-
**> project.org] On Behalf Of casperyc
**> Sent: Thursday, November 18, 2010 11:50 AM
**> To: r-help_at_r-project.org
**> Subject: Re: [R] how exactly does 'identify' work?
**>
**>
**> Hi,
**>
**> I think the problem is
**>
**> 1 - when a linear model is fitted, ploting the qqnorm( test.lm$ res )
**> we dont 'know' what values are actually being used on the y-axis; and
**> how do we refer to the ‘Index’ on the x-axis??
**> therefore, i dont know how to refer to the x and y coordinates in
**> the
**> identify function
**>
**> 2 - i have tried using the stdres function in the MASS library, to
**> extract
**> the standardised
**> residuals and plot them manully, ( using the plot ) function.
**> this way, the problem is we have to SORT the residuals first in
**> increasing order to reproduce the same qqnorm plot, in that case,
**> 'identify'
**> function works, however, that CHANGES the order, i.e. it wont return
**> the
**> original A:Z ( row.names ) label.
**> --
**> View this message in context: http://r.789695.n4.nabble.com/how-
**> exactly-does-identify-work-tp3045953p3049357.html
**> Sent from the R help mailing list archive at Nabble.com.
**>
**> ______________________________________________
**> 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.
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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. Received on Thu 18 Nov 2010 - 20:15:07 GMT

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