ToothGrowth: The Effect of Vitamin C on Tooth Growth in Guinea Pigs
Description
The response is the length of odontoblasts (cells responsible for
tooth growth) in 60 guinea pigs. Each animal received one of three
dose levels of vitamin C (0.5, 1, and 2 mg/day) by one of two delivery
methods, orange juice or ascorbic acid (a form of vitamin C and coded
as VC).
Usage
ToothGrowth
Arguments
Format
A data frame with 60 observations on 3 variables.
[,1]
len
numeric
Tooth length
[,2]
supp
factor
Supplement type (VC or OJ).
References
McNeil, D. R. (1977).
Interactive Data Analysis.
New York: Wiley.
Crampton, E. W. (1947).
The growth of the odontoblast of the incisor teeth as a criterion of
vitamin C intake of the guinea pig.
The Journal of Nutrition, 33(5), 491--504.
10.1093/jn/33.5.491.
# NOT RUN {require(graphics)
coplot(len ~ dose | supp, data = ToothGrowth, panel = panel.smooth,
xlab = "ToothGrowth data: length vs dose, given type of supplement")
# }