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• Subject: Help
• From: drukyul <drukyul@ITC.NL>
• Date: Tue, 5 Nov 1996 15:54:26 -0800
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• Reply-To: FOREST Mailing list on forest research and studies <FOREST@LISTSERV.FUNET.FI>
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I am a student studying forestry in the Netherlands. I was doing linear regressions, testing the
third degree polynomial to come to an equation which I could use to predict the variable of
interest. The general equation tested was, Y = B0 + B1*X + B2*X^2 + B3*X^3, where X = Dia. over
bark at breast height. Regression was carried out between Diameter over bark at breast height as
the independent variable and Annual increment (of conifers, as determined from the increment core
sample) as the dependent variable. The regression was done using a programme called REGVIEW.EXE.
This programme is designed to carry out regression by backward elimination, that is, the
insignificant coefficients from the above equation are removed step by step and gives you the
model that best suits your data. But it so happened in my case that the model it gave me was Y =
B0. What can I interpret from this ? Can anyone guide me where I can find reports or literature
where similar case has been cited ?


P. W. Norbu
e-mail  Drukyul@itc.nl

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