GENERAL CONDITIONS IN NEW ZEALAND 

 STANDARD DEVIATION OF RAINFALL 



43 



780 - 90 



40 



19.02 

 4.36 



STANDARD DEVIATION OF YIELD 



CO-EFFICIENT OF CORRELATION 



PROBABLE ERROR 



=v- 



867.27 



40 



= V 21.68 

 = 4.65 



4- 203.41 



40X4.36X4.65 

 = + .250 



= 1 - (.250)^x6745 



V^Q 



between rainfall and yields in New Zealand as far as it 

 is possible with the information I have been able to 

 collect. 



The method adopted has been to ascertain the co- 

 efficient of correlation between yields and rainfall over 

 a series of years. Rainfall records at Lincoln meteoro- 

 logical station were used, and the rainfall for the seven 

 months (May to November) was taken as the most 

 important. But it is doubtful whether it would not 

 have been more appropriate to have taken the rainfall 

 from August to December, as it is during these months 

 that the crop is really growing and ripening. In the 

 opinion of many persons who are interested in agri- 

 culture, the rainfall for May and June is not of great 

 importance; for the ground is regarded as being moist 

 enough during those months whatever rainfall is ex- 

 perienced, and provided a good spring rainfall is 

 forthcoming, a good yield should follow in any case. 

 But this opens up a further line of investigation, for 

 which time is not available at present. The principle 

 is the same, and the only difference would be to take 

 rainfall statistics for the months August to December, 

 and then proceed along the same lines as are here 

 indicated. 



