R help - Oct 2000 - quasi-symmetry loglinear models

Hi All,

I'm trying to implement a quasi symmetry model for data on twin 
pairs.  A crosstabulation of twin 1 by twin 2 (assumed symmetrical) 
stratified by another variable.  There is a good paper on this by 
Phil (?) McCloud and Darroch in Biometrika (1995) which explains the 
method, but I've not done this before so am not clear how to code 
these models.

Any help would be greatly appreciated.

Regards,

Michael.

----------------------------------------------------------
Michael McStephen          M.McStephen at papyrus.mhri.edu.au
MHRI                       Ph:  +613 9389 2931
Locked Bag 11              Fax: +613 9387 5061
PARKVILLE 3052
VICTORIA
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at
stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._

Hi All,

I'm trying to use the names from a data frame to display data in the 
frame:
> data.n<-names(data) # put names into a vector called data.n
data.n[1]
[1] "ID"
>
> paste("data$",data.n[1],sep="") # create the name of
the column in
the dataframe
[1] "data$ID"
 
> as.symbol(paste("data$",data.n[1],sep=""))
data$ID
> eval(as.symbol(paste("data$",data.n[1],sep="")))
Error in eval(expr, envir, enclos) : Object "data$ID" not
found
> 
I want to be able to list the contents of data$ID by using data.n[1] 
just as I would by typing data$ID at the > prompt.

Thanks for any help.

Michael.

----------------------------------------------------------
Michael McStephen          M.McStephen at papyrus.mhri.edu.au
MHRI                       Ph:  +613 9389 2931
Locked Bag 11              Fax: +613 9387 5061
PARKVILLE 3052
VICTORIA
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at
stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._