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Factors Associated with Variation in the Aggregate Average Yield of New Zealand Wheat (1918–1967)
Author(s) -
Guise John W. B.
Publication year - 1969
Publication title -
american journal of agricultural economics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.949
H-Index - 111
eISSN - 1467-8276
pISSN - 0002-9092
DOI - 10.2307/1237779
Subject(s) - econometrics , yield (engineering) , variance (accounting) , variable (mathematics) , statistics , variables , regression analysis , standard deviation , mathematics , aggregate (composite) , agriculture , standard error , value (mathematics) , regression , economics , ecology , biology , mathematical analysis , materials science , accounting , metallurgy , composite material
An apparently successful test of a “step function” hypothesis about the effect of technological change in the agricultural sector is reported. The effects of weather and other factors on wheat yields are also analyzed. A notable feature of the research was the lack of significance of an ordinary time trend variable, used as a surrogate for technological change, when a detailed specification of these factors was developed. Overall, 98.6 percent of the variance of the dependent variable in the sample was accounted for by a regression relationship involving seven weather and four non‐weather variables, only one of which related to technological change. The potential value of this relationship for forecasting crop yield is indicated by the fact that the standard error of forecast was substantially less than the standard deviation of errors for the present system of pre‐harvest yield estimation.