HISTORY OF WHEAT PRODUCTION IN NEW ZEALAND 123 

 STANDARD DEVIATION OF PRICES 



STANDARD DEVIATION OF SUPPLY 



CO-EFFICIENT OF CORRELATION = 46 x 22 45 x 33 93 



-.440 



PROBABLE EEROB = l- 



.079 



price. 



ties, ' ' the depression of the ' ' eighties, ' ' the South African 

 War, also tended to disturb this natural tendency. The 

 nature and extent of this influence is reserved for special 

 study in the following chapter, but it is expedient here 

 to point out that our co-efficient of correlation is not 

 remarkably low relative to circumstances, and since the 

 probable error is comparatively low we may regard the 

 establishment of correlation as a practical certainty. 

 The accompanying graph* showing the relation between 

 price and area under wheat is interesting as illustrating 

 the influence of price movements on the practice of our 

 farmers in regard to wheat growing. Years of high 

 prices are almost invariably followed by increases in the 

 area sown, and low prices similarly exert an influence 

 in reducing the area. 



8. Competition of other Industries for the Use 

 of the Land. 



1. Sheep Farming. In dealing with the general 

 history of wheat production references were made to 



*8ee page 125. 



