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Date:   Tue, 5 Jun 2001 17:35:26 -0400
Reply-To:   "Eyster, Sandra" <seyster@AIR.ORG>
Sender:   "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:   "Eyster, Sandra" <seyster@AIR.ORG>
Subject:   Re: Computing Mean-Centered Values w/Syntax
Content-Type:   text/plain; charset="iso-8859-1"

I don't have the syntax in front of me but use AGGREGATE to create a file that contains the mean of a variable (or variables). Next merge it back into the original data file. You can then compute the mean-centered value (e.g., compute cvar=var-mvar). This approach has the advantage of avoiding multiple steps and can be done easily for multiple variables.

-----Original Message----- From: Carol Albright [mailto:syzygy@TC.UMN.EDU] Sent: Tuesday, June 05, 2001 5:13 PM To: SPSSX-L@LISTSERV.UGA.EDU Subject: Re: Computing Mean-Centered Values w/Syntax

At 11:17 AM 6/5/01 -0500, you wrote:

>Does anyone know how to create mean-centered values for variables using

>syntax?

>thanks,

>Craig

Hi, Craig

This is what I've done for another project (the statistician said to subtract the mean from the raw value):

1) Compute the means of the variables:

freq vara varb /formats=notable/stats = mean.

2) Compute the centered variable:

Say the mean for VARA is 2.13:

compute varac = (vara - 2.13).

variable labels varac "Variable A Centered Around Mean (var - mean)".

execute.

There might be a zippier way of doing this with macros for a whole bunch of variables.

Carol

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Carol L. Albright, MS | E-Mail : syzygy@tc.umn.edu

Albright Consulting | Phone : 651/699-7218

St. Paul, MN 55105 USA | Research data services

http://www.tc.umn.edu/~syzygy (SPSS tips now on own pages)

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