COMPARISON OF TWO PROCEDURES TO CORRECT THE STANDARD ERROR OF THE QUOTIENT OF RANDOM VARIABLES IN LER INDEX, USED IN INTERCROPPING EXPREMENTS

Euclides Braga MALHEIROS[1]

§    ABSTRACT: The precision of the analysis of variance of the LER index (Land Equivalent Ratio) has been studied by many researchers. The conclusion that can be drawn, when the index is standardized by unique divisors in the same analysis, is that the precision of the analysis of variance is satisfactory. According to Oyejola & Mead (1989), index defined lije this do not present distributional problems since the divisors are constants in the same analysis and the indices are simply sums of the random variables. The problems is that the divisors, even being constants, are random variables and their variability must be considered. In the present work, the precision of the LER index analysis of variance, using computer simulated data, was compared considering two procedures to correct the standard error of the quotient of random variables in LER index. The LER index was standardized by the yield mean of the single crop, when a correction of the standard error was made using the maximum of the standard error of the parts of the sum, according to Oyejola & Mead (1989),and using the average of them. The results show large advantage, referring to the analysis of variance precision, when the average is used.

§    KEYWORDS: Intercropping; correction of the standard error; LER index; analysis of variance precision.

 



[1] Departamento de Ciências Exatas da Faculdade de Ciências Agrárias e Veterinárias - UNESP- 14870-000 - Jaboticabal - SP - Brasil. Bolsista do CNPq.