86 



Journal of Agricultural Research voi. xvi, No. 3 



A glance at these tables shows that there is little correlation between 

 butter fat percentage and the weight of milk or age at test for the Hol- 

 stein-Friesian cows. It seems well before tabulating these coefficients 

 that we consider the effect of increased production in Holstein-Friesian 

 cattle on the percentage of solids-not-fat contained in the milk. Two 

 tables similar to those above are necessary for this comparison. These 

 data are given in Tables VI and VII. 



Table VI. — Correlation surface for the amount of milk produced in one year and the per- 

 centage of solids not fat contained in the milk of Holstein-Friesian cows 



Table VII. — Correlation surface for the variables age at test and percentage of solids not 

 fat for the semiofficial year records of Holstein-Freisian cows 



It will be noticed that in both Tables VI and VII there is one value 

 (in parentheses) far removed from the distribution of the other entries. 

 It seems desirable to determine the correlations with this value included 

 and excluded. Consequently, the correlations will be given both with 

 and without it, since it is highly probable that some error has crept 

 into the determination of the solids for this test. 



