From: Kasper Daniel Hansen <khansen_at_stat.Berkeley.EDU>

Date: Thu 09 Nov 2006 - 05:53:48 GMT

R-devel@r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-devel Received on Thu Nov 09 19:52:49 2006

Date: Thu 09 Nov 2006 - 05:53:48 GMT

On Nov 8, 2006, at 9:44 PM, Kasper Daniel Hansen wrote:

*> Upon further reflection on my part I have realized that my original
**> email was way too harsh - even for the sometimes harsh tone on R-
**> devel.
**>
**> Having spent a few more minutes reflecting on the original question
**> and reading the old thread Robert linked to, it seems that there is
**> indeed some questions about the non-existence of a df argument.
**>
**> I guess it can be interesting in the case where you are comparing to
**> an estimated probability vector and you want to take that estimation
**> into account (which does not seem straightforward, see Peter
**> Dalgaard's old email). In that case a user might be interested in
**> explicitly passing along a df argument.
**>
**> On the other hand, there are several circumstances where I would say
**> a df is unnecessary. One case is when the p value is computed by
**> simulation and another is the case where the argument is a matrix and
**> the function tests for independence (at least it would be highly non-
**> standard to have any other degrees of freedom that the usual one).
**>
**> Since the function returns the statistic it is very easy to directly
**> compute the df by
**> statistic = chisq.test( ... )$statistic
**> p.value = 1 - pchisq(statistic, df = df)
**> (or p.value = pchisq(statistic, df = df, lower.tail = FALSE) ).
*

Ok, I am writing pretty bad here, this paragraph should fo course read

Since the function returns the statistic it is very easy to directly compute the p-value for a given degrees of freedom by

statistic = chisq.test( ... )$statistic p.value = 1 - pchisq(statistic, df = df) (or p.value = pchisq(statistic, df = df, lower.tail = FALSE) ).

*> Altogether I would personally be slightly inclined to say it is
**> better not to provide a df argument - I would think that the
**> possibility of misuse is to high.
**>
**> Kasper
**>
**>
**>
**> On Nov 8, 2006, at 7:40 AM, McGehee, Robert wrote:
**>
*

>> Is Sahotra's abuse sending a wishlist item to R-bugs, or is his error

*>> phrasing a suggestion in the form of a question? It seems others have
**>> commented on the inability to specify df for chisq.test (see:
**>> http://tolstoy.newcastle.edu.au/R/help/05/01/10539.html), and
**>> adding an
**>> option certainly seems like a reasonable suggestion to me.
**>>
**>> And of course, R-FAQ 9.2 does explicitly give a standard for
**>> reporting
**>> wishlist or non-bug items to the R-bugs:
**>> "There is a section of the bug repository for suggestions for
**>> enhancements for R labelled `wishlist'. Suggestions can be
**>> submitted in
**>> the same ways as bugs, but please ensure that the subject line makes
**>> clear that this is for the wishlist and not a bug report, for
**>> example by
**>> starting with `Wishlist:'."
**>>
**>> So if your qualm is with how onerous and manual the R bugs tracking
**>> system is, rather than if the sender sent his question/comment to the
**>> wrong list or in the wrong form, then perhaps an upgrade to the R bug
**>> tracker is in order rather than discouraging sending wishlist
**>> items to
**>> the bugs archiving system.
**>>
**>> Robert
**>>
**>> -----Original Message-----
**>> From: r-devel-bounces@r-project.org
**>> [mailto:r-devel-bounces@r-project.org] On Behalf Of Kasper Daniel
**>> Hansen
**>> Sent: Tuesday, November 07, 2006 10:24 PM
**>> To: sarkar@mail.utexas.edu
**>> Cc: R-devel
**>> Subject: Re: [Rd] Chi-squared test (PR#9350)
**>>
**>> (not cc'ed to R-bugs)
**>>
**>> If this is not a bug why do you abuse the bug report system to ask a
**>> simple question? Now a member of R-core has to use valuable time to
**>> handle this bug report, time that could be far more profitable spent
**>> making improvements to R (or spend it otherwise). This is incredible
**>> selfish behavior.
**>>
**>> Kasper
**>>
**>> On Nov 7, 2006, at 5:41 PM, sarkar@mail.utexas.edu wrote:
**>>
**>>> Full_Name: Sahotra Sarkar
**>>> Version: 2.2.0
**>>> OS: Windows XP
**>>> Submission from: (NULL) (128.83.34.44)
**>>>
**>>>
**>>> This is not a bug: I'm just wondering why chisq.test does not allow
**>>> the
**>>> specification of the degree of freedom (df).
**>>>
**>>> ______________________________________________
**>>> R-devel@r-project.org mailing list
**>>> https://stat.ethz.ch/mailman/listinfo/r-devel
**>>
**>> ______________________________________________
**>> R-devel@r-project.org mailing list
**>> https://stat.ethz.ch/mailman/listinfo/r-devel
**>>
**>>
**>
**> ______________________________________________
**> R-devel@r-project.org mailing list
**> https://stat.ethz.ch/mailman/listinfo/r-devel
*

R-devel@r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-devel Received on Thu Nov 09 19:52:49 2006

Archive maintained by Robert King, hosted by
the discipline of
statistics at the
University of Newcastle,
Australia.

Archive generated by hypermail 2.1.8, at Thu 09 Nov 2006 - 15:30:40 GMT.

*
Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-devel.
Please read the posting
guide before posting to the list.
*