Date:         Wed, 24 Aug 2005 17:49:05 +0100
Reply-To:     starborn@statisticsdoc.com
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Keith Starborn <starborn@statisticsdoc.com>
Subject:      Re: reversing z scores
Comments: To: sarai batchelder <sbatchelder@optonline.net>
In-Reply-To:  <004701c5a8c9$a63c26e0$88ea7745@PC988720711140>
Content-Type: text/plain; charset=ISO-8859-1; format="flowed"

Keith Starborn
www.statisticsdoc.com

Sarai,

In order to reverse the direction of a z score, you can either:

(1) multiply the old Z score by -1   so NEWZ = (-1 * OLDZ)

or

(2) subtract the old z score from 0   so NEWZ = (0 - OLDZ)

Best,

KS


Quoting sarai batchelder <sbatchelder@optonline.net>:

> Hi all,
>
> this seems like it should be simple but I can't figure it out.
>
> I have a variable that I want to convert into z-scores, but I want
> the order to be reversed.  The problem is that I have a series of
> scales of neuropsych functioning that I want to make into z-scores
> and then average, but "good scores" are high on some scales and low
> on other scales.  How to make z-scores that are all interpreted in
> the same direction, so that an average is meaningful?
>
> Thanks,
>
> Sarai Batchelder
>



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