#
# Load a sample of the Wages and Hours of White Men
# in 1981
# downloaded from
# http://www.stat.washington.edu/handcock/594/Data/smallhourswm81.RData
#
load("smallhourswm81.RData")
#
pdf(file = "FigLec8.1.pdf",width=10.5,height=7.5,horiz=T)
par(mfrow=c(1,2))
#
plot(x=hrswm81, y=wagewm81,
  main="Wages and Hours worked for White Men in 1981", 
  xlab = "Hours worked", ylab = "Wage")
fit <- lm(wagewm81 ~ hrswm81)
lines(x=hrswm81, y=fitted(fit))
#
# add a legend
#
legend(x=c(45,45),y=c(5.2,5.2),lty=1,legend=c("linear regression fit"))
#
plot(x=hrswm81, y=wagewm81,
  main="Wages and Hours worked for White Men in 1981", 
  xlab = "Hours worked", ylab = "Wage")
#
fit <- lm(wagewm81 ~ hrswm81 + I(hrswm81^2))
lines(x=hrswm81, y=fitted(fit))
#
fit <- lm(wagewm81 ~ hrswm81 + I(hrswm81^2) + I(hrswm81^3) )
lines(x=hrswm81, y=fitted(fit), lty=2)
#
# add a legend
#
legend(x=c(45,45),y=c(5.2,5.2),lty=1:2,
  legend=c("quadratic fit", "cubic fit"))
#
#xyplot(wagewm81 ~ hrswm81)