Dear Gang, I'm not clear about the form of the model that you're trying to fit, nor what the form of the likelihood would be for such as model, but the short answer is that sem() requires that each covariance among observed variables be for the same observations and hence for the same number (N) of observations.
BTW, I didn't respond to your query to r-help because I was out of town and unable to read email. Regards, John On Mon, 10 Jul 2006 11:36:06 -0400 Gang Chen <[EMAIL PROTECTED]> wrote: > Hi Dr. Fox, > > I posted the following message to the R e-mail list, but didn't get > any response. I was wondering whether you could shed some light on > my problem. > > Thank you very much. > > Gang > > === > > From: [EMAIL PROTECTED] > Subject: Re: [R] Package sem > Date: July 9, 2006 5:49:41 PM EDT > To: [EMAIL PROTECTED] > > Hi, > > I am trying to run some path analysis with Dr. Fox's sem package. The > number N in sem(ram, S, N) is supposed to be the total number of > observations, right? However, in my situation the effective number of > degrees of freedom for each observed variable is estimated by some > auto-regression process, thus each variable bears a different DF. Is > there a way I could run such a path analysis with a vector of DF's in > sem? > > Thanks, > Gang > -------------------------------- John Fox Department of Sociology McMaster University Hamilton, Ontario, Canada http://socserv.mcmaster.ca/jfox/ ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
