Actually, i had checked out the methods of time series (TS), but i had thought it cannot solve it. TS may only considers the autocorrelation of Y in different time, but not Xs. Besides Y, i also have several independent variables. Following your suggestion, i browsed the dynlm package and found it is helpful. Lag function (e.g.lag(x, lag = -k)) may solve the problem. That is, TS plus Lag function may finally solve my task. But one question is how to determine the best k for Y and Xs. Thanks. 2009/3/6 Greg Snow <greg.s...@imail.org>
> I think that the dynlm package was designed for just such a problem. I > also would not be surprised if there are tools in the zoo package to do > this. You should probably check out the time series task view on CRAN as > well. > > Hope this helps, > > -- > Gregory (Greg) L. Snow Ph.D. > Statistical Data Center > Intermountain Healthcare > greg.s...@imail.org > 801.408.8111 > > > > -----Original Message----- > > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > > project.org] On Behalf Of zhijie zhang > > Sent: Thursday, March 05, 2009 8:56 AM > > To: r-h...@stat.math.ethz.ch > > Subject: [R] Does R have function or method to finish my task? > > > > Dear all, > > Does R have function or method to finish the following task. > > Say i have a dataset. The response variable is Y, and the indepedent > > variables are X1, X2, X3, and YEAR. See an example. > > Y X1 X2 X3 X4 > > YEAR > > 13.4 2.8 3.5 2.5 1.8 1990 > > 10.5 1.8 2.4 2 3 1991 > > .... ..... > > In ecology, Y may be not only related with X1, X2, X3 in the same year > > as > > Y, but also may be related with X1, X2, X3 and Y in the previous one , > > two > > or more years as Y. But which year has the closest relationship is not > > know > > and this may be one of the analysis aim. > > Take Year=1995 as an example, > > Y_1995 may be related with > > X1_1995 , X2_1995 , X3_1995, > > X1_1994 , X2_1994 , X3_1994, Y_1994, (previous one year) > > X1_1993 , X2_1993 , X3_1993, Y_1993 (previous two years) > > ... ... > > (previous more years) > > Pay attention to the situation that Y itself may also affect its own > > value > > of the next several years. > > Anybody knows whether R have functions or methods to > > finish the above task. > > I hope i have explained it clearly. Any suggestions or help are > > greatly > > appreciated. > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide > > http://www.R-project.org/posting-<http://www.r-project.org/posting-> > > guide.html > > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
