> From: Ronaldo Reis Jr. [mailto:[EMAIL PROTECTED] > > Hi, > > I make an analysis and depending of the order of the variables, the > significance change, look. [output of glm fits omitted]
> Why this? Because, as the output says: > Terms added sequentially (first to last) When the predictors are not orthogonal (i.e., correlation=0), the question "is variable X significant" depends on the model that's being fitted. The significance test that anova() performs the following comparisons, assuming X1 through X4 are the variables: Y ~ 1 vs. Y ~ X1 Y ~ X1 vs. Y ~ X1 + X2 Y ~ X1 + X2 vs. Y ~ X1 + X2 + X3 Y ~ X1 + X2 + X3 vs. Y ~ X1 + X2 + X3 + X4 > How the best method to select the model (with idade or > without idade)? AIC? That also depends on what you are looking for in the model. If you are looking for interpretation, probably the answer is not to select models, as that could lead to bias in the coefficients of the selected model. HTH, Andy > Thanks > Ronaldo > -- > > Entre dois pecados, eu sempre escolho o que ainda n�o cometi > > --Mae West > -- > |> // | \\ [***********************************] > | ( � � ) [Ronaldo Reis J�nior ] > |> V [UFV/DBA-Entomologia ] > | / \ [36571-000 Vi�osa - MG ] > |> /(.''`.)\ [Fone: 31-3899-2532 ] > | /(: :' :)\ [EMAIL PROTECTED] ] > |>/ (`. `'` ) \[ICQ#: 5692561 | LinuxUser#: 205366 ] > | ( `- ) [***********************************] > |>> _/ \_Powered by GNU/Debian Woody/Sarge > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo> /r-help > ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
