CONTENTS. Til 



PAGE 



Galton's graphic method 44 



Pearson's method 44 



Brief method 45 



Probable error of r 45 



Example 45 



Coefficient of regression 47 



The quantitative treatment of characters not quantitatively meas- 

 urable 47 



The correlation of non-quantitative qualities 49 



Example. 51 



Quick methods of roughly determining the coefficient of correlation. 54 



Spurious correlation in indices 54 



Heredity 55 



Uniparental inheritance 55 



Biparental inheritance 55 



To find the coefficient of correlation between brethren from the 



means of the arrays 56 



Galton's law of ancestral heredity 57 



Mendel's law of inheritance in hybrids 57 



A dissymmetry index 60 



CHAPTER V. 

 SOME RESULTS OF STATISTICAL BIOLOGICAL STUDY. 



General 62 



Variability 62 



General 62 



Man , 63 



Mammalia 65 



Aves 65 



Amphibia 66 



Pisces 66 



Tracheata 66 



Crustacea 66 



Annelida 67 



Brachiopoda 67 



Bryozoa 67 



Mollusca 67 



Echinodermata 68 



Ccelenterata 68 



Protista 69 



Plants 69 



Some types of biological distributions. . 71 



Type 1 71 



Type IV 72 



Type V 72 



Normal 72 



Skewness 72 



Complex distributions 73 



