Date:         Wed, 27 Sep 2006 14:42:36 -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: Computing the median value of a group of variables
Comments: To: Jennifer Thompson <jcthompson@gmail.com>
Comments: cc: Marta García-Granero <biostatistics@terra.es>
In-Reply-To:  <5914fb5e0609270806r5054efe3s7425512e3b97f00@mail.gmail.com >
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At 11:06 AM 9/27/2006, Jennifer Thompson wrote:

>[How to] work out the median value of a group of variables?  I have a
>datafile with just 42 cases but there are 4 sets of 100 variables that
>represent consecutive reaction time responses.

OK if I weigh in? Marta suggested either

>You have to FLIP your dataset, then AGGREGATE the median to a new
>file, backflip (or just open again your original file) and MATCH both
>files together.

or

>No need to tamper with FLIPs AGGREGATEs and other nasty
>transformations. You can easily adapt this MATRIX code to your needs

I haven't looked at the MATRIX code. Marta's done wonders with MATRIX,
more than just about any of us, much more than I have.

But I might, myself, use the first approach, using "wide to long to
wide" logic (my terminology) - in this case, "wide to long to
AGGREGATE." (Hey, Marta - 'nasty' is in the eye of the beholder. You
know what I can do with the transformation language and AGGREGATE: real
power, and quite clean if used properly.)

For "wide to long", VARSTOCASES is almost always cleaner and more
reliable than is FLIP. You'll probably get the MATRIX code working
fine; if not (is this OK, Marta?), give us some test data and I'll give
it a go with VARSTOCASES logic.

-Cheers, and good luck to you,
  Richard