Williams.litters {CountsEPPM}

Number of trials (implantations) of data of Williams (1996).

Description

The data is arranged as a list of grouped counts where the grouping is by dose where dose is included both as a variate (vdose) and as a factor (fdose).

Usage

data(Williams.litters)

Format

The format is: List of 3 $ vdose : num [1:4] 0 0.75 1.5 3 $ fdose : Factor w/ 4 levels "0","0.75","1.5",..: 1 2 3 4 $ number.implants:List of 4 ..$ : num [1:18] 0 0 0 0 0 0 0 0 0 2 ... ..$ : num [1:20] 0 0 0 0 0 0 0 1 0 1 ... ..$ : num [1:17] 0 0 0 0 0 0 0 1 1 2 ... ..$ : num [1:17] 0 0 0 0 0 0 0 0 0 3 ...

Source

Williams D (1996). Overdispersion in logistic linear model. In B Morgan (ed.), Statistics in Toxicology, pp. 75-84, Oxford Science Publications.

Examples

data(Williams.litters)
print(Williams.litters)