Relative brain weights for 51 species of mammal whose average litter size is less than 2 and for 45 species of mammal whose average litter size is greater than or equal to 2.
A data frame with 96 observations on the following 2 variables.
relative brain sizes (1000 * Brain weight/Body weight) for 96 species of mammals
factor variable with levels
Ramsey, F.L. and Schafer, D.W. (2013). The Statistical Sleuth: A Course in Methods of Data Analysis (3rd ed), Cengage Learning.
Sacher, G.A. and Staffeldt, E.F. (1974). Relation of Gestation Time to Brain Weight for Placental Mammals: Implications for the Theory of Vertebrate Growth, American Naturalist 108: 593–613.