#
# EPage 215
#
# 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.
# 
#-----

save_plots = T

#install.packages("MPV")

library(lattice) # needed for xyplot 
library(DAAG)
library(MASS)

set.seed(0)

#bomregions = bomregions[ complete.cases( bomregions ), ] 

nraw.lqs = lqs( northRain ~ SOI + CO2, data=bomregions )
north.lqs = lqs( I(northRain^(1/3)) ~ SOI + CO2, data=bomregions )

#if( save_plots ){ postscript("../../WriteUp/Graphics/Chapter6/prob_14_plot.eps", onefile=FALSE, horizontal=FALSE) }


par(mfrow=c(2,1))
plot( residuals(nraw.lqs) ~ Year, data=bomregions )
plot( residuals(north.lqs) ~ Year, data=bomregions )
par(mfrow=c(1,1))


par(mfrow=c(2,1))
nraw_residuals = residuals(nraw.lqs)
qqnorm( nraw_residuals ); qqline( nraw_residuals, col=2 )

north_residuals = residuals(north.lqs)
qqnorm( north_residuals ); qqline( as.double(north_residuals), col=2 )
par(mfrow=c(1,1))

#if( save_plots ){ dev.off() }

print( coefficients(nraw.lqs) )
print( coefficients(north.lqs) )