"cat.." <cat.b41@GMAIL.COM> wrote > >I'm trying to understand in detail, step by step, how the stepwise >selection process works and I study the following SAS example: >

Mind if I ask why?

>http://www.technion.ac.il/docs/sas/stat/chap39/sect44.htm > >But I'm confused about one thing: The first set of covariates is: cell >smear infil li blast temp. > >At step 0, only the intercept is entered, and, before entering the >step 1, a table is displayed that shows the analysis of effects >eligible for entry. Which includes, at step 0: cell smear infil li >blast temp. > >Is this table supposed to display the Chi-square score of significance >of the estimate of each effect when fitting the model remis = cell >smear infil li blast temp ? > >In that case, why does the code > >proc logistic data=Remission descending outest=betas covout; > model remiss=cell smear infil li blast temp; >run; > >yield chi-square scores that are completely different !! >

Because that will include *all* the independent variables, and all the effects are controlled for the other IVs.

You'd have to try, e.g

proc logistic data=Remission descending outest=betas covout; model remiss=cell; run;

and compare that to the first run result for cell

HTH

Peter

Peter L. Flom, PhD Statistical Consultant www DOT peterflom DOT com