304 



Journal of Agricultural Research 



Vol. XVU, No. 6 



ANALYTICAL DISCUSSION OF VARIATION IN MILK PRODUCTION 



Turning next to the analysis of the variation in mean weekly yield 

 and in fat percentage by fitting skew curves to the observed frequency 

 distributions, we have the results set forth in Tables VII and VIII. 

 Table VII gives the anal3^tical constants for mean weekly yield and 

 Table VIII those for fat percentage. In fitting the curves the combined 

 distributions for the two years 1908 and 1909 have been used throughout 

 in the case of weekly yield. In the case of fat percentage the combined 

 distributions have been used for all ages except 3 and 4 years. Since 

 there was some doubt as to whether, at these ages, the fat distributions 

 for the two years were significantly different from each other, it was 

 thought best to fit the 190S and the 1909 fat distributions separately 

 for both of the ages mentioned. 



TablB VII. — Analytical constants for variation in mean weekly yield 



6 years. 



V/Si. 



Skewness 



d (gallons) 



a (gallons) , 



Mean (sallons). . . 

 Mode (frallons) . . 

 Range (gallons.). 

 +end of range. . . 

 —end of range. . . 

 Yoper cent 



P. E. V^ 



-p.-E.Pi 



P. E. skewness. . 



1,441 



23.9798 



17-7255 



1,830.3431 



.0228 



.1509 



3- 1830 



•1830 



.2977 



.0578 



.0688 



.1686 



2.4485 



13-8413 



13.6727 



1,118 



30. 1002 



21.6903 



986. 7220 



•0173 



•13 13 



3-2965 



-2965 



•5413 



.0240 



.0560 



•1537 



2-7432 



15-2299 



15-0762 



8.28 



± -0435 

 ± .0S70 

 ± .0217 



7-50 

 ± -0494 

 ± .09S8 

 ± .0247 



909 



30-3681 



61.4079 



3,604.8731 



.1346 



.3669 



3.9089 



.90S9 



1-4138 



.0746 



.1302 



•3587 



2-7554 



16.4634 



16. 1047 



35-0959 



55-2151 



4, 201.6107 



.0705 



-2656 



3.4112 



.4112 



.6107 



.0883 



• liiS 



• 3304 

 2.9621 



17.4701 

 17-1397 



7-79 

 ± .0548 

 ± . 1096 

 ± -0274 



6.99 



± .0583 

 ± -1165 

 ± .0291 



712 



35-2890 



80. 0331 



.307.9103 



•1458 



• 3818 



3-4593 



-4593 



.4813 



•2357 



.1661 



•4934 



2.9702 



18.0492 



I7^555S 



6-97 

 ± .0619 

 ± .1238 

 ± -0309 



Constant. 



/3i... 



/32... 



Skewness 



d (gallons) 



a (gallons) 



Mean (gallons) . . 

 Mode (gallons) . 

 Range (gallons). 

 +end of range. . 

 —end of range. . . 



Yo per cent 



P. E. -n/^i 



P.E.Oj 



P. E. skewness. 



8 years. 



637 

 35-2522 

 59-3923 



4,334-0982 

 .0805 



• 2838 

 3-4876 



.4876 



• 7336 

 .0842 

 .1157 

 •3435 



2.9687 

 18.2602 

 17.9167 



7- 03 

 ± • 065s 

 ± • 1309 

 ±•0327 



459 



33.8404 



48-3269 



3,464.0612 



.0603 



-2455 



3.0249 



.0249 



— . 1309 



— -3505 



• 1283 



•3732 



2.9086 



18.5561 



18. 1829 



64.4991 



67-2343 



2-7352 



6.85 



±•0771 



±.1542 



±.0386 



320 



36-9035 



44-3365 



4,387-5182 



•0391 



.1978 



3.2217 



.2217 



.3260 



.0909 



.0895 



.2718 



3-0374 



18.7375 



18.4657 



6-57 

 ±•0924 



±.1847 

 ± . 0462 



202 



44. 3448 



—22.3850 



7,459.8357 



.0057 



-0758 



3-793 5 



•7935 



I. 5698 



.0009 



— .0259 



— .0863 

 1-3296 



18. 1114 

 18-1977 



6.46 

 ±.1163 

 ±-2325 

 ±.0581 



4,642 



116 

 38. I07S 

 4164 

 5S35 

 2491 



4991 

 1970 

 1970 

 3535 

 1203 

 2817 

 8695 

 0866 

 4569 

 5874 

 0305 

 4776 

 4471 

 52 



1534 

 3068 

 0767 



