Date: Sat, 23 Mar 2002 14:00:48 -0500
Reply-To: "Geraldine R. Henderson" <drgerri@attglobal.net>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: "Geraldine R. Henderson" <drgerri@attglobal.net>
Subject: Re: A Really Stupid Question . . .
In-Reply-To: <3C9CC83D.5D490533@fibertel.com.ar>
Content-Type: text/plain; charset="iso-8859-1"
Aha. Sylvia suggested that I recode everything to Factor A (high, low)
and Factor B (present, absent). Thus, I got rid of all self-entered
"1's" and "2's" to avoid confusion. However, my output remains the
same: "reference category=2" and Level 1 vs. Level 2. So, your literal
suggestion no longer holds because there are no more "1's" and "2's."
Help!
Take care,
Gerri
*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Geraldine R. Henderson, Ph.D.
Associate Professor, Marketing Department
Howard University School of Business
2600 Sixth Street, N.W.
Washington, D.C. 20059
202-806-1644 Office/Voicemail
202-318-1277 Fax
drgerri@attglobal.net
-----Original Message-----
From: Hector Maletta [mailto:hmaletta@fibertel.com.ar]
Sent: Saturday, March 23, 2002 1:24 PM
To: Geraldine R. Henderson
Cc: SPSSX-L@LISTSERV.UGA.EDU
Subject: Re: A Really Stupid Question . . .
Geraldine, just be literal: ""reference category =2" means the
reference category is the one which is coded 2, i.e. "Low" in Factor A
and "Absent" in Factor B. The effect of a High level of Factor A, and
the effect of Factor B being Present is measured as a difference against
the effect of A=Low and the effect of B absent, respectivaly. Comparing
level 1 to level 2 means comparing the group coded 1 to the group coded
2 for whichever factor the phrase is applied to.
Hector Maletta
Universidad del Salvador
Buenos Aires, Argentina
"Geraldine R. Henderson" wrote:
>
> Okay, I have been away from Statistical Analysis for a while, back
when
> we ran SAS on a mainframe. Anyway, I am trying to figure out how SPSS
> (10.1 for Windows) operates. I am trying to run planned simple
> contrasts in MANOVA on two factors that had a significant interaction.
> Each of the two factors has only two levels. Factor A is coded such
> that the true value "high" is coded as "1" and the true value "low" is
> coded as "2." Likewise, Factor B is coded such that the true value
> "present" is coded as "1" and absent is coded as "2."
>
> So here is my really stupid question:
> When my SPSS simple contrast on Factor A output tells me the the
> "reference category =2" which I assume is the last category, how do I
> know if the reference category is "high" or "low?" In addition, when
it
> tells me that it is comparing "Level 1" vs. "Level 2," which is which?
> "Present" or "Absent?" How does it assign which level is which? Is
it
> based on order of data entry, ordinal value even for nominal data?
>
> I have tried books, calling SPSS (Statistician will call me back by
EOD
> Monday), AnswerNet, etc. I know that this is a really stupid
> question, but I can't seem to find the answer.
>
> Will someone out there help me once you stop laughing at the idiocy of
> my message?
>
> Thanks, Gerri.
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