2 N. H. Experiment Station 



91.15 per cent purity, and 87 per cent germination, the 

 actual seeding value of the sample is .91 1 5 x .87, or 79 

 per cent. 



A certain amount of variation is to be expected in 

 comparing the results of two or more purity analyses. 

 For this reason a "tolerance" or difference is allowed 

 between the average results of our tests and the guaran- 

 tee in accordance with the following formula. The 

 sample is considered as being made up of two parts, 

 the one being the pure seed and the other the balance 

 of the sample. The tolerance in per cent allowed for 

 the larger part or pure seed is two-tenths of one per 

 cent plus 20 per cent of the lesser part. For instance, 

 if a sample is guaranteed 99.60 per cent pure seed, it 

 may test as low as 99.32 per cent or as high as 99.88 

 per cent and would be "satisfactory." In the same 

 way, a sample guaranteed 92.80 per cent may test as 

 low as 91.17 per cent or as high as 94.43 per cent and 

 be "satisfactory." If a sample is found to be better 

 than the highest figure in the tolerance, it is marked 

 "Above" in this bulledn; if lower than the lowest figure, 

 the actual figure is reported. 



A wider tolerance for germination than for purity is 

 allowed between the results of the test and the guaran- 

 tee, as follows: 



Accordingly, a sample guaranteed 92 per cent germi- 

 nation is "satisfactory" if it tests 86 per cent to 98 per 

 cent. A sample guaranteed 85 per cent may fall as 

 low as 78 per cent or as high as 92 per cent. If a 



