摘要：
1.读取数据jj=scan("http://www.stat.pitt.edu/stoffer/tsa2/data/jj.dat") jj<-scan("http://www.stat.pitt.edu/stoffer/tsa2/data/jj.dat")scan("http://www.stat.pitt.edu/stoffer/tsa2/data/jj.dat")->jj> jj<-scan("http://www.stat.pitt.edu/stoffer/tsa2/data/jj.dat&qu 阅读全文