prats {VGAM} | R Documentation

## 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 andn 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)

[Package VGAM version 1.0-3 Index]