I've been trying to draw quantile linear regression lines across a
scatterplot of my data using
attach(forrq)
plot(PREGNANT,DAY8,xlab="pregnant EPDS",ylab="postnatal
EPDS",cex=.5)
taus <- c(.05,.1,.25,.75,.9,.95)
xx <- seq(min(PREGNANT),max(PREGNANT),100)
for(tau in taus){
f <- coef(rq(DAY8~PREGNANT,tau=tau))
yy <- (f[1]+f[2]*xx)
lines(xx,yy)
}
which is simply the method from the help file with my dataset attached, and the
variable names substituted where appropriate. I get the scatterplot, but no
lines. Any ideas about what's going on? or wrong?
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This works for me:
data(engel)
plot(engel$x, engel$y, xlab="household income", ylab="food
expenditure",
cex=.5)
taus <- c(.05,.1,.25,.75,.9,.95)
lapply(taus, function(tau) abline(coef(rq(y~x, data=engel, tau=tau))))
HTH,
Andy
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of
> david_foreman at doctors.org.uk
> Sent: Monday, July 19, 2004 9:53 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] why won't rq draw lines?
>
>
> I've been trying to draw quantile linear regression lines
> across a scatterplot of my data using
>
> attach(forrq)
> plot(PREGNANT,DAY8,xlab="pregnant EPDS",ylab="postnatal
> EPDS",cex=.5)
> taus <- c(.05,.1,.25,.75,.9,.95)
> xx <- seq(min(PREGNANT),max(PREGNANT),100)
> for(tau in taus){
> f <- coef(rq(DAY8~PREGNANT,tau=tau))
> yy <- (f[1]+f[2]*xx)
> lines(xx,yy)
> }
> which is simply the method from the help file with my dataset
> attached, and the variable names substituted where
> appropriate. I get the scatterplot, but no lines. Any ideas
> about what's going on? or wrong?
>
>
> ______________________________________________________________
> _________
> Most doctors use http://www.Doctors.net.uk e-mail.
> Move to a free professional address with spam and virus protection.
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
>
>
The example in help(rq) works for me. I presume the problem is not due to attach(forrq) as you get the scatterplot. Why don't you try printing 'xx' and 'yy' inside the loop and see what you get. On Mon, 2004-07-19 at 14:53, david_foreman at doctors.org.uk wrote:> I've been trying to draw quantile linear regression lines across a scatterplot of my data using > > attach(forrq) > plot(PREGNANT,DAY8,xlab="pregnant EPDS",ylab="postnatal EPDS",cex=.5) > taus <- c(.05,.1,.25,.75,.9,.95) > xx <- seq(min(PREGNANT),max(PREGNANT),100) > for(tau in taus){ > f <- coef(rq(DAY8~PREGNANT,tau=tau)) > yy <- (f[1]+f[2]*xx) > lines(xx,yy) > } > which is simply the method from the help file with my dataset attached, and the variable names substituted where appropriate. I get the scatterplot, but no lines. Any ideas about what's going on? or wrong? > > > _______________________________________________________________________ > Most doctors use http://www.Doctors.net.uk e-mail. > Move to a free professional address with spam and virus protection. > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html >
Thanks, this works for me as well, though the lines extend beyond the Y axes (sometimes). I'm very grateful. ---------- Original Message ---------------------------------- From: "Liaw, Andy" <andy_liaw at merck.com> Date: Mon, 19 Jul 2004 10:04:55 -0400>This works for me: > >data(engel) >plot(engel$x, engel$y, xlab="household income", ylab="food expenditure", > cex=.5) >taus <- c(.05,.1,.25,.75,.9,.95) >lapply(taus, function(tau) abline(coef(rq(y~x, data=engel, tau=tau)))) > >HTH, >Andy > >> -----Original Message----- >> From: r-help-bounces at stat.math.ethz.ch >> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of >> david_foreman at doctors.org.uk >> Sent: Monday, July 19, 2004 9:53 AM >> To: r-help at stat.math.ethz.ch >> Subject: [R] why won't rq draw lines? >> >> >> I've been trying to draw quantile linear regression lines >> across a scatterplot of my data using >> >> attach(forrq) >> plot(PREGNANT,DAY8,xlab="pregnant EPDS",ylab="postnatal >> EPDS",cex=.5) >> taus <- c(.05,.1,.25,.75,.9,.95) >> xx <- seq(min(PREGNANT),max(PREGNANT),100) >> for(tau in taus){ >> f <- coef(rq(DAY8~PREGNANT,tau=tau)) >> yy <- (f[1]+f[2]*xx) >> lines(xx,yy) >> } >> which is simply the method from the help file with my dataset >> attached, and the variable names substituted where >> appropriate. I get the scatterplot, but no lines. Any ideas >> about what's going on? or wrong? >> >> >> ______________________________________________________________ >> _________ >> Most doctors use http://www.Doctors.net.uk e-mail. >> Move to a free professional address with spam and virus protection. >> >> ______________________________________________ >> R-help at stat.math.ethz.ch mailing list >> https://www.stat.math.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide! >> http://www.R-project.org/posting-guide.html >> >> > > >------------------------------------------------------------------------------ >Notice: This e-mail message, together with any attachments, contains information of Merck & Co., Inc. (One Merck Drive, Whitehouse Station, New Jersey, USA 08889), and/or its affiliates (which may be known outside the United States as Merck Frosst, Merck Sharp & Dohme or MSD and in Japan, as Banyu) that may be confidential, proprietary copyrighted and/or legally privileged. It is intended solely for the use of the individual or entity named on this message. If you are not the intended recipient, and have received this message in error, please notify us immediately by reply e-mail and then delete it from your system. >------------------------------------------------------------------------------ > >________________________________________________________________________ >Doctors.net.uk e-mail protects you from viruses and unsolicited messages >________________________________________________________________________ >_______________________________________________________________________ Most doctors use http://www.Doctors.net.uk e-mail. Move to a free professional address with spam and virus protection.