Rcommander and simple chisquare

John Fox

Thu, Sep 15, 2005 9:59 AM

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))

 >
 >
 > > ______________________________________________

Rcommander and simple chisquare

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