[R] lme model: Error in MEEM

From: Christoph Lehmann <christoph.lehmann_at_gmx.ch>
Date: Thu 18 Aug 2005 - 22:38:02 EST


Hi,
We have data of two groups of subjects: 32 elderly, 14 young adults. for each subject we have 15 observations, each observation consisting of a reaction-time measure (RT) and an activation maesure (betadlpcv). since we want to analyze the influence of (age-)group and RT on the activation, we call:

lme(betadlpcv ~ RT*group, data=our.data, random=~ RT |subject)

this yields:
Error in MEEM(object, conLin, control$niterEM) :

        Singularity in backsolve at level 0, block 1 In addition: Warning message:
Fewer observations than random effects in all level 1 groups in: lme.formula(betadlpcv ~ RT * group, data = patrizia.data, random = ~RT |

what's the problem here?

thanks for your kind help
christoph

-- 
Lust, ein paar Euro nebenbei zu verdienen? Ohne Kosten, ohne Risiko!
Satte Provisionen für GMX Partner: http://www.gmx.net/de/go/partner



______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html

Received on Thu Aug 18 22:44:53 2005

This archive was generated by hypermail 2.1.8 : Fri 03 Mar 2006 - 03:39:53 EST