#
# Written by:
# -- 
# John L. Weatherwax                2009-04-21
# 
# email: wax@alum.mit.edu
# 
# Please send comments and especially bug reports to the
# above email address.
# 
#-----

library(DAAG)
attach(oddbooks)

# Compute our derived features from the base features: 
volume = thick * height * breadth
area = breadth * height
density = weight / volume 

#postscript("../../WriteUp/Graphics/Chapter5/prob_4_plot_wv.eps", onefile=FALSE, horizontal=FALSE)

# Part (a):
#plot( log(weight) ~ log(volume) )
#m1 = lm( log(weight) ~ log(volume) )
plot( log(density) ~ log(volume) )
m1 = lm( log(density) ~ log(volume) )
abline(m1)
summary(m1)

#dev.off()

#postscript("../../WriteUp/Graphics/Chapter5/prob_4_plot_wa.eps", onefile=FALSE, horizontal=FALSE)

# Part (b):
#plot( log(weight) ~ log(area) )
#m2 = lm( log(weight) ~ log(area) )
plot( log(density) ~ log(area) )
m2 = lm( log(density) ~ log(area) )
abline(m2)
summary(m2)

#dev.off()