[R] Rcommander and simple chisquare
John Fox
jfox at mcmaster.ca
Thu Sep 15 18:59:11 CEST 2005
Dear Christian,
The Rcmdr assumes that you have a data frame with the original data, in
which the variable in question is a factor. The frequency distribution is
constructed for the factor. Thus, in your example, you'd have 100
observations classified on a two-category factor. What you enter directly
are the hypothesized probabilities.
I hope this helps,
John
--------------------------------
John Fox
Department of Sociology
McMaster University
Hamilton, Ontario
Canada L8S 4M4
905-525-9140x23604
http://socserv.mcmaster.ca/jfox
--------------------------------
> -----Original Message-----
> From: Christian Jost [mailto:jost at cict.fr]
> Sent: Thursday, September 15, 2005 11:38 AM
> To: John Fox; 'Philippe Grosjean'
> Cc: r-help at stat.math.ethz.ch
> Subject: RE: [R] Rcommander and simple chisquare
>
> Dear John and Philippe,
>
> thanks for your replys, I finally found this menu, but I am
> somewhat at a loss how I should enter the observed
> frequencies. To take my example below, If I enter a
> one-column data.frame with the numbers 61 and 39, John's
> indicated menu is not highlighted. If I add a second column
> containing some factor, the menu is highlighted by I cannot
> select the first column. However, if I edit the data and
> declare the first column to be of type 'character' I can
> select it in the menu dialog and declare the expected
> frequencies, but the chisquare output doesn't make any sense.
> For the moment I cannot make any sense of that :-( Any help
> most appreciated, or a link to the tutorial/faq that explains
> such kind of problems.
>
> Thanks, Christian.
>
> At 11:31 -0400 15/09/05, John Fox wrote:
> >Dear Philippe,
> >
> >This does a chi-square test of independence in a contingency
> table, not
> >a chi-square goodness-of-fit test (which is done in the Rcmdr via
> >Statistics
> >-> Summaries -> Frequency distribution).
> >
> >Regards,
> > John
> >
> >--------------------------------
> >John Fox
> >Department of Sociology
> >McMaster University
> >Hamilton, Ontario
> >Canada L8S 4M4
> >905-525-9140x23604
> >http://socserv.mcmaster.ca/jfox
> >--------------------------------
> >
> >> -----Original Message-----
> >> From: r-help-bounces at stat.math.ethz.ch
> >> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Philippe
> >> Grosjean
> >> Sent: Thursday, September 15, 2005 7:32 AM
> >> To: Christian Jost
> >> Cc: r-help at stat.math.ethz.ch
> >> Subject: Re: [R] Rcommander and simple chisquare
> >>
> >> Hello,
> >>
> >> Just look at Statistics -> Contingency tables. There is
> an option
> >> for making the chi square test there.
> >> Best,
> >>
> >> Philippe Grosjean,
> >>
> >> ..............................................<°}))><........
> >> ) ) ) ) )
> > > ( ( ( ( ( Prof. Philippe Grosjean
> > > ..............................................................
> >>
> >> Christian Jost wrote:
> >> > In this years biostat teaching I will include Rcommander (it
> >> indeed > simplifies syntax problems that makes students
> frequently
> >> miss the > core statistical problems). But I could not
> find how to
> >> make a simple > chisquare comparison between observed frequencies
> >> and expected > frequencies (eg in genetics where you expect
> >> phenotypic frequencies > corresponding to 3:1 in standard
> >> dominant/recessif alleles). Any idea > where this
> feature might be
> >> hidden? Or could it be added to > Rcommander?
> >> >
> >> > Thanks, Christian.
> >> >
> >> > ps: in case I am not making myself clear, can
> Rcommander be made
> >> to > perform > >> chisq.test(c(61,39),p=c(0.75,0.25))
> >> >
> >> >
> > > > ______________________________________________
>
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