Results of an experiment where two groups of 16 female rats were fed different diets during pregnancy and lactation periods. One group's diet contained a chemical under review, and the other one was a control. For each litter, the number of pups alive at 4 days, and the number of pups weaned (i.e. that survived the 21-day lactation period) were recorded.
A data frame with 32 rows and 3 variables:
|[, 1]||group||Either control or treated group.|
|[, 2]||i||Pups weaned.|
|[, 3]||n||Pups alive at 4 days.|
Weil CS. 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: 177-182.