APPLICABILITY OF A COEFFICIENT OF CORRELATION 339 



Plant 3. A r = 548 inflorescences. 



r xa = + -0941 -0285 

 r*z = -2849 .0265 



For 1913. Individual plants. All inflorescences, 

 Plant i. A r = 1135 inflorescences. 



r xa = .0067 .0200 



r xz = .2125 .0191 

 Plant 2. A r = 975 inflorescences. 



r xa = .0821 .0214 



r xx = .3681 .0187 

 Plant 3. A r = 912 inflorescences. 



r xa = .0360 .0223 



r xg = - .2342 .0211 



For all the samples of inflorescences in which there is at least one 

 abnormal pedicel the correlations between the total number of pedicels 

 and the number of normal pedicels is positive in sign and perhaps sta 

 tistically significant, but low in actual magnitude. Thus the number of 

 abnormal pedicels increases on the average as the total number of pedi 

 cels per inflorescence becomes larger. The relationships are, however, 

 very slight indeed. 



For these five series the correlation between the total number of pedi 

 cels and the deviation of the abnormal pedicels from their probable 

 value, is negative in sign. Thus the larger inflorescences have a rela 

 tively smaller proportion of abnormal pedicels than do those with a 

 smaller total number of pedicels. 



In the four series in which the wholly normal inflorescences are in 

 cluded, the correlations between total number of pedicels and number of 

 abnormal pedicels is positive in 1909 but negative throughout and insig 

 nificant in magnitude in 1913. The three series from individual shrubs 

 studied in 1913 show low but significantly negative correlations between 

 the total number of pedicels per inflorescence and the deviation of the 

 number of abnormal inflorescences from their probable value. The con 

 stant for the heterogeneous data of 1909 is positive but insignificant. 



Taking the data altogether, there can be no reasonable doubt that the 

 relative number of abnormal pedicels decreases as the total number of 

 abnormal pedicels increases. 



This is shown in diagram 3, which represents the regression of the 

 deviation of the number of abnormal rays from their probable value on 



GENETICS 3: Jl 1918 



