#
# Epage 
#
# 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(alr3)
data(shortshoots)
attach(shortshoots)

# 5.2.1: a scatterplot
# epage
#
plot( Day, ybar, xlab="Day", ylab="Number of stem units")

one_pct_quant <- quantile( SD, c(0.01) )
SD[1]         <- (1.e-3) * one_pct_quant
wm            <- lm( ybar ~ Day, weights=1./( SD^2 ) )
uwm           <- lm( ybar ~ Day )

postscript("../../WriteUp/Graphics/Chapter5/prob_2.eps", onefile=FALSE, horizontal=FALSE)
plot( Day, ybar, xlab="Day", ylab="Number of stem units")
abline( wm )
#abline( uwm ) 
dev.off()

summary(wm)
summary(uwm)