Dear all,
I'm looking for how can I input a linear model with an arma model,like log(y) = 8.95756 + 0.0346414^t - 0.1*t^2 + ut ut=-0.296ut-1+at-0.68at-1 where log(y) is qudratic function ,for the time series trend, and get then get the residuals from the first function. " obersvations value - the fit value = ut" and fit an ARIMA(1,1,1) model for ut. anyway,how can I combine this two models together as a group ? my purpose is to to use this mixed model forecast 'y' can you help me? I will very appreciate it. ______________________________________________ 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