\begin{Schunk}
\begin{Sinput}
 dat.kj <- read.table("data/data_kj.dat", header=T)
 dat.kj$v1 <- dat.kj$v1-mean(dat.kj$v1)
 dat.kj$v2 <- dat.kj$v2-mean(dat.kj$v2)
 dat.kj$s1 <- dat.kj$s1-mean(dat.kj$s1)
 dat.kj$s2 <- dat.kj$s2-mean(dat.kj$s2)
\end{Sinput}
\end{Schunk}
