3.4.3 The Quantile-Quantile Plot (QQ-plot)

# Fig. 3.8.: QQ plots for Au, log(Au) library(StatDA) data(chorizon) # need Au data: Au=chorizon$Au n=length(Au) pdf("fig-3-8.pdf",width=9,height=4.5) par(mfcol=c(1,2),mar=c(4,4,2,2)) qqplot.das(Au,distribution="lnorm",col=1,envelope=FALSE,datax=TRUE,ylab="Au [ g/kg]", xlab="Quantiles of lognormal distribution", main="",line="none",pch=3,cex=0.7) mtext(expression(mu),side=1,line=3.05,at=72.5,cex=1.2) qqplot.das(log10(Au),distribution="norm",col=1,envelope=FALSE,datax=TRUE, ylab="Au [ g/kg]", xlab="Quantiles of standard normal distribution", main="",line="none",pch=3,cex=0.7, xaxt="n") axis(1,at=log10(alog<-sort(c((10^(-50:50))%*%t(10)))),labels=alog) mtext(expression(mu),side=1,line=3.05,at=0.40,cex=1.2) dev.off()

# Fig. 3.9: QQ plots for Au, log(Au) with line and envelope library(StatDA) data(chorizon) # need Au data: Au=chorizon$Au n=length(Au) pdf("fig-3-9.pdf",width=9,height=4.5) par(mfcol=c(1,2),mar=c(4,4,2,2)) qqplot.das(Au,distribution="lnorm",col=1,envelope=0.95,datax=TRUE,ylab="Au [ g/kg]", xlab="Quantiles of lognormal distribution", main="",line="quartiles",pch=3,cex=0.7) mtext(expression(mu),side=1,line=3.05,at=72.5,cex=1.2) qqplot.das(log10(Au),distribution="norm",col=1,envelope=0.95,datax=TRUE, ylab="Au [ g/kg]", xlab="Quantiles of standard normal distribution", main="",line="quartiles",pch=3,cex=0.7, xaxt="n") axis(1,at=log10(alog<-sort(c((10^(-50:50))%*%t(10)))),labels=alog) mtext(expression(mu),side=1,line=3.05,at=0.40,cex=1.2) dev.off()