prats {VGAM}

Pregnant Rats Toxological Experiment Data

Description

A small toxological experiment data. The subjects are fetuses from two randomized groups of pregnant rats, and they were given a placebo or chemical treatment. The number with birth defects were recorded, as well as each litter size.

Usage

data(prats)

Format

A data frame with the following variables.

treatment

A 0 means control; a 1 means the chemical treatment.

alive, litter.size

The number of fetuses alive at 21 days, out of the number of fetuses alive at 4 days (the litter size).

Details

The data concerns a toxological experiment where the subjects are fetuses from two randomized groups of 16 pregnant rats each, and they were given a placebo or chemical treatment. The number with birth defects and the litter size were recorded. Half the rats were fed a control diet during pregnancy and lactation, and the diet of the other half was treated with a chemical. For each litter the number of pups alive at 4 days and the number of pups that survived the 21 day lactation period, were recorded.

Source

Weil, C. S. (1970) Selection of the valid number of sampling units and a consideration of their combination in toxicological studies involving reproduction, teratogenesis or carcinogenesis. Food and Cosmetics Toxicology, 8(2), 177–182.

References

Williams, D. A. (1975). The Analysis of Binary Responses From Toxicological Experiments Involving Reproduction and Teratogenicity. Biometrics, 31(4), 949–952.

See Also

betabinomial, betabinomialff.

Examples

prats
colSums(subset(prats, treatment == 0))
colSums(subset(prats, treatment == 1))
summary(prats)