Experimental Error in Crop Tests 
Ratio of 
Col. 10 to 
Col. 9 
Deviation 
of group 
mean from 
: field mean* 
1 1 1 1 1 1 1+1 1 1 1 iT 
iii 
"|[ 
sliilliiiliiiliiliilii 
11 
sliiiiiiiliiiiiiiiiiii!!! 
% 
sc-ooooooocoot-ocooooc-t-t-t-t~t-t-t-t-t-t-t-t-t>o 
yield per acre for four plat-; averaged 
1 
t 
O 
3 
