library(StatDA)
data(moss)
sel=c("Ag","Al","As","B","Ba","Bi","Ca","Cd","Co","Cr","Cu","Fe","Hg","K","Mg",
"Mn","Mo","Na","Ni","P","Pb","Rb","S","Sb","Si","Sr","Th","Tl","U","V","Zn")
x=moss[,sel]
# Closure problem with log-centring transformation
xgeom=10^apply(log10(x),1,mean)
x2=x/xgeom
x2.obj=log10(x2)
pdf("fig-14-1.pdf",width=9,height=4.5)
par(mfcol=c(1,2),mar=c(4,4,2,2))
rs1=apply(x,1,sum)
plot(rs1,ylab="Sum over all variables", xlab="Sample order",
cex.lab=1.2, cex=0.75, pch=3, lwd=1)
abline(h=quantile(rs1,c(0.25,0.75),col=gray(0.6)))
rs2=apply(x2,1,sum)
plot(rs2,ylab="Sum over all variables (opened)", xlab="Sample order",
cex.lab=1.2, cex=0.75, pch=3, lwd=1)
abline(h=quantile(rs2,c(0.25,0.75),col=gray(0.6)))
dev.off()