Flury (version 0.1-3)

treesf: Tree data

Description

Measurement on black cherry trees

Usage

data(treesf)

Format

'treesf' is familiar data frame with observations on 31 trees with respect to the following 3 variables.

Diameter

Diameter measured one foot above ground (inches)

Height

Height (feet)

Volume

Volume (cubic feet)

Source

Ryan, B.F., B. Joiner and T.A. Ryan (1976) Minitab Handbook (2nd edition) Boxton: Duxbury Press (page 278)

Details

Note that the diameter needs to be coverted to feet (12 inches in 1 foot) before use. Assuming cone shaped trunks, the colume of wood available should be found from: $V = (\pi/12) D^{2} H$. By taking logarithms of the variables it is possible to fit $\log V = \log(\pi/12) + 2 \log D + \log H$ by using lm().

References

Flury, B.D. (1997) A First Course in Multivariate Statistics, Springer NY

Examples

data(treesf)
## Not run: 
# Y <- log(treesf$Volume)
# X1 <- log(treesf$Diameter / 12)
# X2 <- log(treesf$Height)
# trees.lm <- lm(Y ~ X1 + X2)
# summary(trees.lm)
# log(pi/12)
# vcov(trees.lm)## End(Not run)