| ToothGrowth {datasets} | R Documentation |
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).
ToothGrowth
A data frame with 60 observations on 3 variables.
| [,1] | len | numeric | Tooth length |
| [,2] | supp | factor | Supplement type (VC or OJ). |
| [,3] | dose | numeric | Dose in milligrams/day |
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")