APPLICABILITY OF A COEFFICIENT OF CORRELATION 345 



DIAGRAM 6. Regression of the deviation of the number of cotyledons and of the 

 number of leaves from their probable numbers on the total number of leaf homologs 

 in Phaseolus. Note that the theoretical lines and the empirical means are identical 

 but opposite in sign. 



Whence we deduce : 



Stage i, rig = + .649 .027. 

 Stage 3, r lg = .071 .047. 

 Stage 5, r lz = -534 .038. 



These results bring out especially well the analytical value of the 

 method here proposed. The correlations between total length and head 

 length are roughly the same in the three stages of development. The 

 correlation between total length and deviation of head length is at first 

 strongly positive, then sensibly zero in the third stage and finally becomes 

 negative and of the order .5 in the fifth stage. 



GENETICS 3: Jl 1918 



