R help - Apr 2010 - Just about "approximate F-test"

Hi, Dear R community,

These is a paper of "Wheat Grain Yield Response to N Application
Evaluated through Canopy Reflectance".

This paper of "Materials and Methods" said "A single regression
equation
relating A and B was derived for each location using PROC NLIN (SAS
Inst. 1990). Slopes and intercepts for the independent regressions were
compared with an *approximate F-test* (Mead et al. 1993) to determine if
a single relationship could be used across environments."

I can not understand the "approximate F-test", and I donot know how to
use this test to compare coefficients of regression in R.

Does anyone know that?

Thanks a lot in advance.

-- 
Sincerely
Guoqiang LI
Agri521@gmail.com
http://agri520.cn
-- 


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>
> This paper as attachment had beed send to list. you can find the result
table in page 597.
I donot have this book of "Statistical methods in agriculture and
experimental biology" in hand. I find some pages of the nine and ten
chapter in google books.

http://books.google.com/books?id=VhQJ6ZPCPZEC&printsec=frontcover&hl=en#v=onepage&q&f=false

>    
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