| methyl {MCPAN} | R Documentation |
NTP bioassay data: effect of methyleugenol on skin fibroma
Description
NTP bioassay of methyleugenol: 200 male rats were randomly assigned to 4 treatment groups with balanced sample size 50. Individuals in treatment group 0, 1, 2, and 3 received doses of 0, 37, 75, and 150 mg methyleugenol per kg body weight, respectively. The response variable tumour is the presence of skin fibroma at time of death. The variable death gives individual time of death, with a final sacrifice of surviving animals at 730 days after begin of the assay.
Usage
data(methyl)Format
A data frame with 200 observations on the following 3 variables.
- group
a factor with levels 0, 1, 2, 3, specifying dose groups 0, 37, 75, and 150 mg/kg, respectively
- tumour
a numeric vector, specifying whether a tumour was present at time of death
- death
a numeric vector, specifying the time of death
Source
National toxicology program (2000).
References
SD Peddada, GE Dinse, JK Haseman (2005): A survival-adjusted quantal response test for comparing tumour incidence rates. Applied Statistics 54, 51-61.
Examples
data(methyl)
# raw tumour proportions:
table(methyl[c("group", "tumour")])
# time of death:
boxplot(death~group, data=methyl, horizontal=TRUE)