488 TRANSMISSION 



COEFFICIENTS OF HEREDITY FOR DIFFERENT RELATIONSHIPS 



that the coefficient of regression is a direct measure of the pull 

 of the back ancestry, or that it directly measures the dissimilarity 

 between parent and offspring as shown in the regression table. 

 In fact, we note that when regression is perfect, then the coeffi- 

 cient of regression is zero ; and when there is no regression 

 (perfect correlation), then the regression coefficient is large. 

 This is brought out in the diagram on the following page. 



This diagram is a geometrical exhibit of the regression table 

 of statures (page 480) It is simply a reproduction of that table, 

 omitting the frequencies and putting in crosses (x) to repre- 

 sent the means of the horizontal arrays 2 (column 18). 



1 Pearson, Grammar of Science, pp. 458-460. 



2 The mean of offspring in this table is 68 inches, and we have assumed this 

 value to be, for the present purpose, near enough to the mean of mid-parents and 

 of the race to take the horizontal and vertical lines marked 68 as passing through 

 the mean of the table. 



