148 



Maine Agricultural Experiment Station. 1920. 



themselves knowing that the data on which these correlations 

 are based are such that the values of the correlations are their 

 true values. 



TABLE 1. 



Coefficients of Correlation for Butter-Fat Per cent of a Given 

 Year when Correlated with Other Given Years. 



AGE CORRELATED. 



Age with 

 which cor- 

 related 



2:0—3:0 



3:0—4:0 



4:0—5:0 



5:0—6:0 



2:0—3:0 





+0.5277±.0368 



+0.5288-K0390 

 +0.6071±.0349 



+0.5846-1-. 0382 



3:0 — 4:0 



+0.5277-K036S 

 +0.5288-K0390 

 +0.5846-H0382 

 +0.5956-K0407 

 +0.6068-K0452 

 +0.5695±.0468 



+ 0.5739±.0787 



+0.5836-*-. 0384 



4:0—5:0 



+0.6071-K0349 

 +0.5836-K0384 

 +0.5861-K0426 

 +0.2470-+-.0640 

 +0.4311±.0533 



+0.5250±.1121 



+0.6781-K0310 



5:0—6:0 



+0.6781-4-.0310 

 +0.5236-1-.0460 

 +0.5668-K0447 

 +0.4475±.0498 



+ 0.5163±.0674 





6:0—7:0 

 7:0—8:0 



8:0—10:0 



10:0 and 



above 



+0.5529-K0417 

 + 0.4S3J+.0480 

 + 0.5638±.0382 



+ 0.4138±-0747 





Age with 

 which cor- 

 related 



6:0—7:0 



7:0—8:0 



8:0—10:0 



10:0 and above 



2:0—3:0 

 3:0—4:0 

 4:0—5:0 

 5:0—6:0 



6:0—7:0 



+0.5956-K0407 

 +0.5861-K0426 

 +0.5236-i-.0460 

 +0.5529±.0417 



+ 0.6068-+-.0452 

 +0.2470-1-.0640 

 +0.5668-K0447 

 +0.4830-K0480 

 +0.5594+.0420 



+0.5695+.0468 

 + 0.4311-t-.0533 

 +0.4475-K0498 

 +0.5638-1-.0382 

 +0.4678-1-.0434 

 + 0.6004±.0349 



+0.5739-K0787 

 +0.5250-K1121 

 +0.5163-K0674 

 +0.4138-1-.0747 

 +0.3196-1-.0788 



7:0 — 8:0 



+0.5594-K0420 

 + 0.4678±.0434 



+ 0.3196±.0788 



+0.4137-H0659 



8:0 — 10:0 



+0.6004±.0349 

 +0.4137±.0659 



+0.52944-.0436 



10:0 and 

 above 



+0.5294+.0436 





Table i gives the correlations and their probable errors for 

 all ages at which the lactation records were divided. The ver- 

 tical columns as in the preceding tables for the other constants 

 of the correlation surfaces give the correlations of the butter- 

 fat percentage of the ages heading the column with the butter- 

 fat percentage at the ages indicated on the left hand margin of 

 the table. As will be noted the correlations necessary to give 

 the complete set of correlations for any age are repeated e. g. 

 the correlation of 2 years butter-fat percentage with that at 3 

 years is +0.5277 ±.0368 and appears in the two year column on 

 line with the three year age. The correlation of the three years 



