18 BULLETIN 897, U. S. DEPARTMENT OF AGRICULTURE. 
in each case if four or five packages were weighed together. The 
average error in determining the true average by the operator’s 
method is the average deviation of single packages, while the aver- 
. Average deviation 
age error by weighing five together is ———2=——__—— 
obtained. 


AccuRACY—- AVERAGE DEVIATION 
FROIG AVERACE WEIGHT. 
FIG. 1. 
RELATION OF SPEED To ACCURACY OF PACKING 
BY MACHINE. 
KEY © MAKE OF MACHINE #/. 
x MAKE OF MACHINE €$Z. 
© MAKE OF MACHINE #3. 
GB MAKE OF MACHINE# E. 
@ MAKE OF MACHINE #8. 
These chances compare more favorably with 1 in 1,000 and indi- 
cate that an appreciable error can be eliminated by a little more 
careful.supervision of the machine. 
While the errors under average conditions of speed and an errone- 
ous method of setting are not as small as might be expected, the 
possibilities for increase in accuracy by reduction of speed and proper 
methods of setting leave little doubt that machines could meet 
the calculated maximum errors of hand weighing without any ap- 
preciable difficulty. 
i . Recaleu- 
lating the chances on this basis, the results shown in Table 14 are 
- wore 
x ws we gt Sime herd: 
