Measurements on a Selection of Books
The allbacks data frame gives measurements
on the volume and weight of 15 books, some of which
are softback (pb) and some of which are hardback (hb). Area
of the hardback covers is also included.
allbacks
This data frame contains the following columns:
book volumes in cubic centimeters
hard board cover areas in square centimeters
book weights in grams
a factor with levels
hb hardback, pb paperback
The bookshelf of J. H. Maindonald.
print("Multiple Regression - Example 6.1")
attach(allbacks)
volume.split <- split(volume, cover)
weight.split <- split(weight, cover)
plot(weight.split$hb ~ volume.split$hb, pch=16, xlim=range(volume), ylim=range(weight),
ylab="Weight (g)", xlab="Volume (cc)")
points(weight.split$pb ~ volume.split$pb, pch=16, col=2)
pause()
allbacks.lm <- lm(weight ~ volume+area)
summary(allbacks.lm)
detach(allbacks)
pause()
anova(allbacks.lm)
pause()
model.matrix(allbacks.lm)
pause()
print("Example 6.1.1")
allbacks.lm0 <- lm(weight ~ -1+volume+area, data=allbacks)
summary(allbacks.lm0)
pause()
print("Example 6.1.2")
oldpar <- par(mfrow=c(2,2))
plot(allbacks.lm0)
par(oldpar)
allbacks.lm13 <- lm(weight ~ -1+volume+area, data=allbacks[-13,])
summary(allbacks.lm13)
pause()
print("Example 6.1.3")
round(coef(allbacks.lm0),2) # Baseline for changes
round(lm.influence(allbacks.lm0)$coef,2)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.