CHAPTER IX. 



CREAMEPvY CALCTLATION. 



Find the Average Per Cent of Fat. — In calculating the 

 average per cent of fat from a number of cows, or the milk 

 furnished by the different patrons, the mistake of adding the 

 tests of all the samples together and dividing the sum by the 

 total number of samples tested is often made. ]\Iilk from 

 different patrons, or from different cows, will always vary, 

 some in quality and some in quantit}^, and in order to get a 

 correct average test, both quantity and qualitj' must be taken 

 into consideration. The wrong way of calculating the average 

 percentage may be illustrated as follows : 



Sample. Milk Delivered. Per cent Fat. 



1 50 lbs. 5.0 



2 100 " 4.5 



3 500 " 3.0 



4 300 " 3.5 



4)16% 

 4 



The average test, according to the wrong method, =4*^,. 

 The correct way of calculating the average percentage may 

 be illustrated as follows: 



105 



