prats.RdA 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.
data(prats)A data frame with the following variables.
A 0 means control;
a 1 means the chemical treatment.
The number of fetuses alive at 21 days, out of the number of fetuses alive at 4 days (the litter size).
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.
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.
Williams, D. A. (1975). The Analysis of Binary Responses From Toxicological Experiments Involving Reproduction and Teratogenicity. Biometrics, 31(4), 949–952.
prats
#> treatment alive litter.size
#> 1 0 13 13
#> 2 0 12 12
#> 3 0 9 9
#> 4 0 9 9
#> 5 0 8 8
#> 6 0 8 8
#> 7 0 12 13
#> 8 0 11 12
#> 9 0 9 10
#> 10 0 9 10
#> 11 0 8 9
#> 12 0 11 13
#> 13 0 4 5
#> 14 0 5 7
#> 15 0 7 10
#> 16 0 7 10
#> 17 1 12 12
#> 18 1 11 11
#> 19 1 10 10
#> 20 1 9 9
#> 21 1 10 11
#> 22 1 9 10
#> 23 1 9 10
#> 24 1 8 9
#> 25 1 8 9
#> 26 1 4 5
#> 27 1 7 9
#> 28 1 4 7
#> 29 1 5 10
#> 30 1 3 6
#> 31 1 3 10
#> 32 1 0 7
colSums(subset(prats, treatment == 0))
#> treatment alive litter.size
#> 0 142 158
colSums(subset(prats, treatment == 1))
#> treatment alive litter.size
#> 16 112 145
summary(prats)
#> treatment alive litter.size
#> Min. :0.0 Min. : 0.000 Min. : 5.000
#> 1st Qu.:0.0 1st Qu.: 6.500 1st Qu.: 8.750
#> Median :0.5 Median : 8.500 Median :10.000
#> Mean :0.5 Mean : 7.938 Mean : 9.469
#> 3rd Qu.:1.0 3rd Qu.:10.000 3rd Qu.:10.250
#> Max. :1.0 Max. :13.000 Max. :13.000