R help - May 2004 - Superposing data on boxplot

Hi folks,

I have a vaiable Y and an associated factor Z at several (13)
levels.

  boxplot(Y~Z)

produces a nice array of boxplots, one for each level of Z,
and each duly labaelled with its level of Z.

I would like to superpose on each boxplot the actual data
points which it represents, i.e. do something conceptually
(though not in real R) expressed as

  points(Y~Z)

or

  points(Z,Y)

It can be done "with bare hands" along the lines of

  B<-boxplot(Y~Z)
  x<-bxp(B)
  X<-rep(x,ngroups)
  points(X,Y)

where ngroups is the number of data at each level of Z,
*provided* the data are pre-sorted by level of Z and in the
same order as these levels occurr in the boxplot. But of course
they're not!

OK, I could do this by hand as well, but now it's getting a bit
tedious, and I'm wondering if there's a better way.

Thanks for any suggestions,
Ted.


--------------------------------------------------------------------
E-Mail: (Ted Harding) <Ted.Harding at nessie.mcc.ac.uk>
Fax-to-email: +44 (0)870 167 1972
Date: 04-May-04                                       Time: 15:48:23
------------------------------ XFMail ------------------------------

Try:

y = rnorm(50)
z = factor(rep(1:5, each=10))
boxplot(y~z, horizontal=TRUE)
stripchart(y~z, add=TRUE)


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 
> Ted.Harding at nessie.mcc.ac.uk
> Sent: Tuesday, May 04, 2004 10:48 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] Superposing data on boxplot
> 
> 
> Hi folks,
> 
> I have a vaiable Y and an associated factor Z at several (13)
> levels.
> 
>   boxplot(Y~Z)
> 
> produces a nice array of boxplots, one for each level of Z,
> and each duly labaelled with its level of Z.
> 
> I would like to superpose on each boxplot the actual data
> points which it represents, i.e. do something conceptually
> (though not in real R) expressed as
> 
>   points(Y~Z)
> 
> or
> 
>   points(Z,Y)
> 
> It can be done "with bare hands" along the lines of
> 
>   B<-boxplot(Y~Z)
>   x<-bxp(B)
>   X<-rep(x,ngroups)
>   points(X,Y)
> 
> where ngroups is the number of data at each level of Z,
> *provided* the data are pre-sorted by level of Z and in the
> same order as these levels occurr in the boxplot. But of course
> they're not!
> 
> OK, I could do this by hand as well, but now it's getting a bit
> tedious, and I'm wondering if there's a better way.
> 
> Thanks for any suggestions,
> Ted.
> 
> 
> --------------------------------------------------------------------
> E-Mail: (Ted Harding) <Ted.Harding at nessie.mcc.ac.uk>
> Fax-to-email: +44 (0)870 167 1972
> Date: 04-May-04                                       Time: 15:48:23
> ------------------------------ XFMail ------------------------------
> 
> ______________________________________________
> 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
> 
>

What about:

y<-rnorm(100);z<-sample(1:7,100,T);boxplot(y~z);points(y~z)

Peter Wolf

Ted Harding wrote:
>Hi folks,
>
>I have a vaiable Y and an associated factor Z at several (13)
>levels.
>
>  boxplot(Y~Z)
>
>produces a nice array of boxplots, one for each level of Z,
>and each duly labaelled with its level of Z.
>
>I would like to superpose on each boxplot the actual data
>points which it represents, i.e. do something conceptually
>(though not in real R) expressed as
>
>  points(Y~Z)
>
>or
>
>  points(Z,Y)
>
>It can be done "with bare hands" along the lines of
>
>  B<-boxplot(Y~Z)
>  x<-bxp(B)
>  X<-rep(x,ngroups)
>  points(X,Y)
>
>where ngroups is the number of data at each level of Z,
>*provided* the data are pre-sorted by level of Z and in the
>same order as these levels occurr in the boxplot. But of course
>they're not!
>
>OK, I could do this by hand as well, but now it's getting a bit
>tedious, and I'm wondering if there's a better way.
>
>Thanks for any suggestions,
>Ted.
>
>
>--------------------------------------------------------------------
>E-Mail: (Ted Harding) <Ted.Harding at nessie.mcc.ac.uk>
>Fax-to-email: +44 (0)870 167 1972
>Date: 04-May-04                                       Time: 15:48:23
>------------------------------ XFMail ------------------------------
>
>______________________________________________
>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
>  
>