[R] [O/T] undergrads and R

John Fox jfox at mcmaster.ca
Wed Apr 26 17:28:20 CEST 2006

Dear Ales,

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Ales Ziberna
> Sent: Wednesday, April 26, 2006 5:21 AM
> To: John Fox
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] [O/T] undergrads and R
> Dear John Fox,
> thank you for your reply. I appologize for not finding the 
> "sort.names" 
> option myself.
> As for the option of choosing several variables at a time, I 
> would like to see this possibility everywhere where possible. 
> Let me give a few
> examples:
> 1. Calculating the mean of several variables (for example, I 
> often want to compute the mean of a set of variables 
> measuring the same concept) 2. Recoding a set of variables 
> with the same rule

These would be useful and easy to do (though for 2. I'd have to provide a
way to name the new variables). BTW, it would help to have a complete set of
suggestions: I'd probably not have thought of 2. (You could send me your
suggestions off-list.) I intend to work on a new version of the Rcmdr this
summer, and, although I can't promise to incorporate all suggestions, I'll
certainly consider them carefully.

> 3. Transforming a set of variables from 
> factor to numeric or vice verse. 

This could get a bit convoluted, since the numeric-to-factor dialog asks you
(optionally) to specify level names and rename the factor. I don't currently
provide for converting factors to numeric, and would worry about misuse
(though you can do this as a recode).

> (This would be especially useful when using data read from 
> SPSS, as all variables with labels are converted to factors. 
> These are often ordinal variables measured on 5 or more point 
> scale, which are often as close as you can get in social 
> sciences to interval variables. However for most of the 
> analysis (like regression, factor analysis ...), they have to 
> be treated as numeric.)

Couldn't you do this with a redesigned Recode dialog?

> As to how this should be done, I agree that a check-box to 
> select all numeric variables might be to "no thingking" 
> approach. I would just like to have an option to select 
> several variables, the same way as is done now in for example 
> factor analysis.
> I do understand that you want the students to think what they 
> are doing. 
> However I would like to present them the R commander as an 
> alternative to SPSS also for doing their assignments for 
> other courses and I do not believe they would be willing to 
> make the change if they have to do so much "clicks" just to 
> compute averages for let say 20 variables.
> I personally think that it is enough that the software does 
> not allow you (or the students) to do "wrong things" (like 
> computing a mean of the factor), especially not without 
> thinking about it.
> Another option I would like are:
> 1. An option to save (or actually to not delete) the results 
> of let say factor analysis, so I could use them for further analysis.

What would you like to save? Currently, you can save factor scores. The R
Commander is designed around an active data set and an active statistical
model. I'm open to incorporating other data structures, but suspect that in
most instances that would lead me outside the boundaries of the R Commander
or require a major redesign. Anyway, it's hard to tell without some more
information about what you'd like.

> 2. Currently, if I create a factor via command line, it is 
> not recognized my the menus (for example, I can not do a 
> frequency table). 
>   If I select a different data frame and then again the 
> previous one as the active data frame, the new factor is now 
> recognized in the menus. So I would also be satisfied by a 
> refresh option for the active data frame.

If I follow this properly, then it doesn't seem to be correct. For example,
if the data frame Data is the Rcmdr active data set then the command

Data$new.variable <- ...

executed in the R console or in the Rcmdr Command window will immediately
make the variable new.variable accessible in the Rcmdr.


> That would be all for now. Thanks again for the reply and for 
> creating Rcmdr in the first place.
> Best regards,
> Ales
> John Fox pravi:
> > Dear Ales,
> > 
> >> -----Original Message-----
> >> From: Ales Ziberna [mailto:aleszib at gmail.com]
> >> Sent: Tuesday, April 25, 2006 1:15 AM
> >> To: Richard M. Heiberger
> >> Cc: r-help at stat.math.ethz.ch; John Fox
> >> Subject: Re: [R] [O/T] undergrads and R
> >>
> >> I will be also using R commander with undergrad students, who 
> >> actually already have some experience with R, however they 
> have been 
> >> using it more as programing language than a statistical tool and I 
> >> want to get them more familiar with this aspect of R.
> >>
> >> First, when I had my first look at R commander, I really liked it, 
> >> however, when I did a little more experiments, I found it quite 
> >> frustrating at times, especially by the fact that when computing a 
> >> certain statistics (for example mean), you can select only one 
> >> variable at the time. Are there any plans to change this, 
> so that a 
> >> number of variables could be chosen?
> > 
> > This was a deliberate choice, made to discourage students from 
> > computing statistics without thinking about them, but perhaps it's 
> > wrongheaded. I'd be interested to hear what people think.
> > 
> > It would be very simple to change the Numerical Summaries dialog to 
> > permit more than one variable to be selected (in fact you 
> could do it 
> > and recompile the package if you wished). Are you referring only to 
> > the "Statistics -> Summaries -> Numerical summaries" dialog, or are 
> > there other places where you'd like more than one variable to be 
> > selected? Would you like a check-box to select all numeric 
> variables?
> > 
> > More generally, I'm open to considering suggestions for 
> improving the Rcmdr.
> > 
> >> I would also prefer to have the variables sorted the same 
> way as they 
> >> are in the data frame and and not alphabetically.
> > 
> > See the sort.names Rcmdr option, described in ?Commander.
> > 
> > Regards,
> >  John
> > 
> >> If this two (what I believe minor) things could be 
> improved, I would 
> >> find R commander much more usable.
> >>
> >> Otherwise, I find it a grate package, especially when working with 
> >> social sciences students.
> >>
> >> Does anyone else have similar filings.
> >>
> >> Best regards,
> >> Ales Ziberna
> >>
> >> Richard M. Heiberger pravi:
> >>> This semester for the first time I have been using the
> >> combination of
> >>> R, R Commander (John Fox's package providing a menu-driven
> >> interface
> >>> to R), and RExcel (Erich Neuwirth's package for 
> interfacing R with 
> >>> Excel).  The audience is the introductory Statistics class for 
> >>> Business undergradutes.  The short summary is that I think the 
> >>> combination works well for this audience.
> >>>
> >>> I will be talking on my experience at the useR! conference
> >> in June.  I
> >>> added several additional menu items to Rcmdr for our 
> group.  I sent 
> >>> the January ones (prior to the beginning of the semester)
> >> to John Fox in January.
> >>> I will send another batch of menu items, those constructed
> >> during the
> >>> semester, as soon as the semester is complete.
> >>>
> >>> The goal is to hide most of the programming from the 
> students.  But 
> >>> not all of it.  I think it is very important for any user 
> of a menu 
> >>> system to have at least a rudimentary idea of the
> >> programming steps behind the menu.
> >>> Rcmdr supports this goal since it functions by generating R
> >> language
> >>> statements from the menu selections and displaying the
> >> generated statements.
> >>> For example, I will casually change the cex or ylim of a 
> generated 
> >>> plot statement.  I post the script window (generated and edited
> >>> statements) from each class to the course website.  I do
> >> not post the output window.
> >>> ______________________________________________
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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
> >>>
> > 
> >
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