CORRELATION 



109 



above method of determining the value of a correlation 

 coefficient was tested by arranging in a similar manner 

 data with regard to stature which had already been 

 treated in the form of a complete correlation table. 

 The whole number of fathers was divided into two 

 groups containing the individuals above and below a 

 certain stature, and the same was done in the case 

 of the sons. And the separation into two groups was 

 made in several different ways by taking the dividing 



PARENTAL CORRELATION OF COAT COLOURS IN HORSES. 



line between the groups at various heights. By 

 applying to the statistics disposed in these various 

 arrangements the same method as was applied to the 

 statistics of horse colour already referred to, values 

 varying between 0-52 and 0-6 were obtained for 

 parental correlation ; whereas the value arrived at by 

 the more usual and reliable method was 0-514. It 

 would therefore appear that there is with this method 

 a tendency to obtain too high a figure, as compared with 

 that derived from the method of the complete correla- 

 tion table. When this source of inaccuracy is taken 



