#
# 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(physics1)
attach(physics1)

if(is.null(version$language) == FALSE) require(alr3) else library(alr3)
if(is.null(version$language) == FALSE) data(physics1)

m1 <- lm(y~x,weights=1/SD^2,data=physics1)
s1 <- summary(m1)
print(s1,signif.stars=FALSE)
print(anova(m1),signif.starts=FALSE)

m2 <- update(m1, ~.+I(x^2))
s2 <- summary(m2)
print(s2,signif.stars=FALSE)
print(anova(m2),digits=6)

postscript("../../WriteUp/Graphics/Chapter5/prob_7.eps", onefile=FALSE, horizontal=FALSE)

if(is.null(version$language) == FALSE)
  plot(physics1$x,physics1$y,xlab=expression(paste("x=",s^(-1/2))),ylab="Cross section, y")
else
  plot(physics1$x,physics1$y,xlab="x=s^(-1/2)",ylab="Cross section, y")
abline(m1)
a <- seq(.05,.35,length=50)
lines(a,predict(m2,data.frame(x=a)),lty=2)

dev.off() 

anova(m1,m2)