Date: Sat, 16 Jul 2011 11:22:42 +0200
Reply-To: John F Hall <johnfhall@orange.fr>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: John F Hall <johnfhall@orange.fr>
Subject: Re: Syntax for SAMPLE
In-Reply-To: <1310759107267-4591971.post@n5.nabble.com>
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David
Tried your syntax, but had to modify it a bit.
*Marso sample .
* data set 'ql4gb1975.sav' .
* variables: var544 (happy), var545 (lifesat), age .
compute happy = var544.
compute lifesat = var545 .
compute caseid = serial .
*** OK here we go **.
SPSS doesn't like SCRAMBLE and I can't find it anywhere in the Syntax
Reference Guide, so I dumped it. The new file has four variables, but only
one case. I was looking to create a data file with up to n cases
corresponding to the number of samples drawn. I can then run SPSS to
demonstrate the distributions of sample statistics with:
Freq MLIFESAT MEANAGE PctVHapp /for not /his .
Also the variables SAMPLE (all with value 101) CASEID ( 1 to 300) and
GPCOUNT (1 to 300) are appended to the existing data set, which I don't
particularly want, and the number of cases has dropped from 932 to 300,
which I definitely don't want! Some of this complex syntax is new to me, but
I did use Algol intensively in the 1960s (to manage and analyse survey data)
so I can follow the logic. I haven't tried Bruce's syntax yet, or Dave
Nicholls' earlier version, but if I can get something that works, it will be
a valuable learning aid. Gives me something to do instead of gardening in
the rain or catching up on 300 or so films, dramas and documentaries
recorded from TV!
John
johnfhall@orange.fr
www.surveyresearch.weebly.com
PS If you haven't already seen it, get Bruce to send you the slideshow.
-----Original Message-----
From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU] On Behalf Of
David Marso
Sent: 15 July 2011 21:45
To: SPSSX-L@LISTSERV.UGA.EDU
Subject: Re: Syntax for SAMPLE
"Assume data set is BSA89.sav, N is 3000 and I want 100 samples of size 300:
then to save mean lifesat, mean age and % very happy (code 3 on happy) as
variables in a separate file with 100 cases (one for each sample)."
Here you go John,
enjoy ;-)
---
*** OK here we go **.
**First of all oversample **.
LOOP SAMPLE=1 TO 100.
+ DO IF UNIFORM(1) < .12 .
+ XSAVE OUTFILE "Samples.sav" / KEEP caseid lifesat age happy sample.
+ END IF.
END LOOP.
*ONE OF THE ONLY Places you NEED an EXECUTE *.
EXECUTE.
GET FILE "samples.sav".
FREQ SAMPLE.
* Using same ideas as what I posted to Cindy Gregory *
COMPUTE SCRAMBLE=UNIFORM(1).
SORT CASES BY SAMPLE SCRAMBLE.
IF $CASENUM=1 OR LAG(SAMPLE) NE SAMPLE GPCount=1.
IF MISSING( GPCount) GPCount=LAG(GPCount)+1.
*ONE OF THE ONLY Places you NEED an EXECUTE *.
EXECUTE.
SELECT IF GPCount LE 300.
FREQ SAMPLE.
AGGREGATE OUTFILE *
/ BREAK SAMPLE
/ MLIFESAT MEANAGE = MEAN(lifesat age)
/ PctVHapp=PIN(happy,3,3).
John F Hall wrote:
>
> David
>
> It was just a thought, and I was only trying to help!
>
> I once had a similar problem when trying to introduce students to
> inferential statistics. I'd have say 24 students and a survey with 1800
> cases for a lab session. Each student was asked to sample n from N with a
> different SET SEED starting point. This was in the days of 16 VDU's
> connected to a remote Vax mainframe (12 working if you were lucky and
> severe
> time constraints if we didn't want to get locked in the building, or get
> away before the Arsenal match finished up the road) not modern PCs and
> distance learning. The idea was to get 3 samples each to yield 72
> statistics (mean lifesat, % happy or whatever) which we then plotted (on
> the
> chalk-board) hopefully to demonstrate a distribution with an approximately
> normal distribution. Sometimes it worked, sometimes it didn't (usually
> because sampling 30 from 3000 isn't as stable as 300 from 3000) but the
> students learned a lot from the attempt and understood what we were trying
> to do, especially that the sampling distribution of the mean was
> approximately normal even if the variable itself was not (eg age)
>
> Now, how about some syntax to do what I need for a new tutorial for the
> website?
>
> Assume data set is BSA89.sav, N is 3000 and I want 100 samples of size
> 300:
> then to save mean lifesat, mean age and % very happy (code 3 on happy) as
> variables in a separate file with 100 cases (one for each sample).
>
> Have a nice weekend.
>
> John
>
> johnfhall@orange.fr
> www.surveyresearch.weebly.com
>
>
>
>
>
>
>
>
> -----Original Message-----
> From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU] On Behalf Of
> David Marso
> Sent: 15 July 2011 19:33
> To: SPSSX-L@LISTSERV.UGA.EDU
> Subject: Re: Syntax for SAMPLE
>
> It makes *NO* sense at all to use SAMPLE within a DO REPEAT.
> Think about that for a moment ;-)
>
> When you do something like
> DO REPEAT X= a b c d / Y = e f g h / Z= ae be cg dh.
> COMPUTE Z=X/Y.
> END REPEAT.
>
> what do you end up with?
> 4 new variables on *EACH* case...
> i.e. DO REPEAT handles TRANSFORMATIONS and applies to each case.
> How would SAMPLE fit into a DO REPEAT?
>
> --
> View this message in context:
>
http://spssx-discussion.1045642.n5.nabble.com/Syntax-for-SAMPLE-tp4591268p45
> 91568.html
> Sent from the SPSSX Discussion mailing list archive at Nabble.com.
>
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