2 N. H. Experiment Station 



actual seeding value of the sample is .9115 x .87, or 79 per 

 cent. 



A certain amount of variation is to be expected in com- 

 paring 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 guarantee 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 "satis- 

 factory." If a sample is found to be better than the high- 

 est figure in the tolerance, it is marked "Above" in this 

 bulletin; 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 guarantee, 

 as follows : 



Guarantee Allowable variation 



per cent per cent 



90 or over 6 



80 or over but less than 90 7 



70 or over but less than 80 8 



60 or over but less than 70 9 



Less than 60 10 



Accordingly, a sample guaranteed 92 per cent germina- 

 tion 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 sample tests higher 

 than the per cent of variation allowed, it is marked 

 "Above" in this bulletin, or, if it tests below the variation 

 allowed, the actual figure is reported. 



