attach("/u/maechler/S/goodies.Data/")
gewichte_read.table("/u/sfs/ueb/datasets/body.brain.dat",header=T)
attach(gewichte)
{ps.do(file="body.brain.ps")
par(mfrow=c(2,1), mar=par("mar")-c(1,-6,+3,-6))
#plot(Body.Weight[-c(6,14)],Brain.Weight[-c(6,14)],pch="o")
plot(Body.Weight,jitter(Brain.Weight,2),pch=5,xlab="Körpergewicht",ylab="Hirnmasse")
title(sub="Körpergewicht")
#plot(Body.Weight,Brain.Weight)
plot(log(Body.Weight),log(Brain.Weight),pch=5,xlab="log(Körpergewicht)",ylab="log(Hirnmasse)")
title(sub="log(Körpergewicht)")
ps.end()}


mean(log(Body.Weight))
 3.028283
mean(log(Brain.Weight))
4.428471
sum((log(Body.Weight)-mean(log(Body.Weight)))^2)/24
10.50226
sum((log(Brain.Weight)-mean(log(Brain.Weight)))^2)/24
6.448081
sum((log(Body.Weight)-mean(log(Body.Weight)))*(log(Brain.Weight)-mean(log(Brain.Weight))))/24
 7.900441

reg.gewicht_lm(log(Brain.Weight)~log(Body.Weight))
summary(reg.gewicht)


Coefficients:
                   Value Std. Error t value Pr(>|t|) Signif 
     (Intercept) 2.15041 0.20060    10.72   0        ***   
log(Body.Weight) 0.75226 0.04572    16.45   0        ***   
Signif. codes:  0  `***'  0.001  `**'  0.01  `*'  0.05  `.'  0.1  ` '  1 

{ps.do(file="body.brain.reg.ps")
par(mar=par("mar")-c(1,-4,+3,-4))
plot(log(Body.Weight),log(Brain.Weight),pch=5,xlab="log(Körpergewicht)",ylab="log(Hirnmasse)")
abline(reg.gewicht$coefficients[1],reg.gewicht$coefficients[2])
ps.end()}