182 WHEAT PRODUCTION IN NEW ZEALAND 



The standard deviations thus found are not directly 

 comparable, for the averages of the two series differ. 

 I have, therefore, calculated the co-efficient of variation,* 

 which is the ratio of the standard deviation to the 

 average for each series, multiplied by 100. This co- 

 efficient for English prices was 16-64, and for New 

 Zealand prices was 18-99, showing a difference of 13 

 per cent., for if we represent the co-efficient of variation 

 for New Zealand prices as 100, then that for English 

 prices is 87. The significance of the result is that the 

 degree of variation in New Zealand prices is greater than 

 that in English prices, or, in other words, English prices 

 are more consistently near their average than New 

 Zealand prices over the period. 



Pursuing the investigation a little further, I have 

 calculated the mean yearly movement for the two series 

 over the period, that is, the mean of the difference 

 between the average annual prices. In the case of 

 English wheat, the mean yearly movement was 4 -3d., 

 and the figure for New Zealand 6 -6d., showing a much 

 greater average yearly fluctuation in the case of New 

 Zealand wheat prices. But the difference is greater 

 when we compare these calculations with the average 

 annual price for the period, for this figure is 4s. 2d. for 

 English wheat, and 3s. 7d. for New Zealand wheat. 

 Thus the mean yearly variation in the price of English 

 wheat is 8 -6 per cent, of the average price ; but for New 

 Zealand wheat it is 15-2 per cent, of the average price 

 for the period. From this calculation, then, the annual 

 fluctuations in the price of New Zealand wheat are about 

 100 per cent, greater than corresponding fluctuations 

 for English wheat prices. 



*See Appendix III. 



