Date:         Fri, 2 Jul 2004 13:57:22 -0400
Reply-To:     Richard Ristow <wrristow@mindspring.com>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Richard Ristow <wrristow@mindspring.com>
Subject:      Re: LOGISTIC REGRESSION: VARIABLES=...BY [var]
Comments: To: Marta García-Granero <biostatistics@terra.es>
In-Reply-To:  <43673992.20040702084947@terra.es>
Content-Type: text/plain; charset="iso-8859-1"; format=flowed

At 02:49 AM 7/2/2004, Marta García-Granero wrote:

>THe syntax [for LOGISTIC REGRESSION] defines specific interaction terms.
>For example:
>
>LOGISTIC REGRESSION VAR=kyphosis WITH age starvert age BY starvert
>   /CRITERIA = PIN(.05) POUT(.10) ITERATE(20) CUT(.5) .
>
>This syntax models the dependent variable Kyphosis as a function of:
>
>- Age
>- Starvert
>- The interaction between the two above

Hurray, Marta! THANK you. This is EXACTLY what I was looking for.

>I always use "*" to indicate interaction terms, it looks clearer to me:
>
>LOGISTIC REGRESSION VAR=kyphosis WITH age numvert starvert age*starvert
>   /CRITERIA = PIN(.05) POUT(.10) ITERATE(20) CUT(.5) .

An excellent idea. Among other things, it makes the pairwise nature of the
specification much more apparent. "BY" has the look of applying to the
whole preceding variable list (as I worried about).

>HTH,  Marta

It certainly does! Again, THANKS!
Richard