120 



George A. Sacher 



There are 63 species for which body weight, brain weight 

 and Hfespan values were tabulated. Most orders of placental 

 mammals are represented, the most important omissions 

 being the bats and marine mammals. Common logarithms of 

 the numbers were used in the statistical analysis. Simple and 

 multiple linear regressions were computed. The statistical 



1.0 



BRAIN WEIGHT - GRAMS 

 10 30 100 300 1000 3000 



LOG,, 



2 

 BRAIN WEIGHT 



3.0 



Fig. 3. Relation of lifespan to brain weight for the same 63 

 species shown in Fig. 2. Symbols as defined in legend to 



Fig. 2. 



formulae are presented in lucid fashion by Hald (1952). 

 Appendix 1 contains the means and standard errors of the 

 variables, the regression coefficients and their standard errors, 

 the total variances of the variables, and their residual vari- 

 ances after removing the variance in regression. With the 

 information provided the total, partial and multiple correla- 

 tion coefficients can also be computed. 



