R: NTP bioassay data: effect of methyleugenol on skin fibroma

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)

[Package MCPAN version 1.1-21 Index]