On Sun, Jan 23, 2005 at 03:10:18PM -0500, [EMAIL PROTECTED] wrote: > Hi R-Help! > > My question: I have lifetime/failure data of machines with different > stress levels and i think an weibull/extreme value distribution would > fit this data. So I did: > > model1 <- survreg(Surv(lfailure)~stress,data=steel,dist="extreme") > > (where lfailure=log(failure)) > > Now I would like to do a likelihood ratio test to test the hypothesis > > H0: location parameters of the extreme value distribution are equal > for each stress level. > > So in order to perform the likelihood ratio test I need the likelood > of the model under > > HA: location parameters are not equal (i.e. each stress level has its > slope and intercept). > > How can I do this?
Stratify on stress level. -- Göran Broström tel: +46 90 786 5223 Department of Statistics fax: +46 90 786 6614 Umeå University http://www.stat.umu.se/egna/gb/ SE-90187 Umeå, Sweden e-mail: [EMAIL PROTECTED] ______________________________________________ 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