The Effect of Vitamin C on Tooth Growth in Guinea Pigs
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
A data frame with 60 observations on 3 variables.
|factor||Supplement type (VC or OJ).||[,1]|
C. I. Bliss (1952) The Statistics of Bioassay. Academic Press.
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. http://jn.nutrition.org/content/33/5/491.full.pdf
require(graphics) coplot(len ~ dose | supp, data = ToothGrowth, panel = panel.smooth, xlab = "ToothGrowth data: length vs dose, given type of supplement")