Thank you very much Marc Schwartz and Neuro LeSuperHéros! At last I got what I expected, of course, with help of your messages. What a great day!
Best, Cao ______________________________________________ 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
