Re: Significant difference - Means

Posted by JOHN ANTONAKIS on Dec 19, 2006; 8:45am
URL: http://spssx-discussion.165.s1.nabble.com/Significant-difference-Means-tp1072801p1072818.html

Hi Jan:

I agree that the 3.5 is not a perfect measure. However, If Samir believes
that 3.5 represents the population mean (with a sample of 1,000 the
standard error should be very small) then that is precisely the case in
which one would use the single-sample test.

If he just wants to compare the means of the two groups then I agree that
the independent sample t-test is more appropriate (because it takes into
account the standard error of the population mean).

Regards,
John

At 09:30 19.12.2006 +0100, Spousta Jan wrote:

>I am very sorry, but this would be wrong in this case. Because the number
>3.5 is not a constant known with (almost) no error, but a sample
>statistics based on the 1000 respondents. Therefore the
>Independent-samples T-test should be used as I've written in my previous
>posting.
>
>Jan
>
>-----Original Message-----
>From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of
>John Antonakis
>Sent: Tuesday, December 19, 2006 9:25 AM
>To: [hidden email]
>Subject: Re: Significant difference - Means
>
>If you wiysh to test the mean of a particular group against the mean of a
>particular value then you can use the single-sample t-test (from the Menus
>Analyze/Compare Means/One sample t-test), or use the syntax:
>
>T-TEST
>    /TESTVAL = 3.5
>    /MISSING = ANALYSIS
>    /VARIABLES = VAR00001
>    /CRITERIA = CI(.95) .
>
>HTH,
>J.
>
>At 09:05 19.12.2006 +0100, =?iso-8859-2?Q?Samir_Omerovi=E6?= wrote:
> >Hi to all,
> >
> >
> >
> >My first question is what test should I use if I need to assess the
> >significance of the mean of some subgroup in comparison the mean of the
> >total population. For example I have 1000 respondents that answered a
> >question on 7-point scale. Their mean/average is 3,5. I have 500
> >students among those 1000 respondents with mean/average 2,9. I want to
> >know if these values are significantly different.
> >What test should I use in SPSS?
> >
> >
> >
> >Thanks to all in advance.
> >
> >
> >
> >Samir
> >
> >
> >
> >GfK BH
> >
> >Centar za istrazivanje trzista i javnog mnijenja d.o.o.
> >
> >
> >
> >Samir Omeroviæ
> >
> >Researcher
> >
> >
> >
> >71 000  Sarajevo, Skenderija 44
> >
> >Bosna i Hercegovina
> >
> >
> >
> >
> >
> >Tel: [phone]
> >
> >Fax: [phone]
> >
> >www.gfk.ba
> >
> >www.gfk.com
> >
> >
> >
> >
> >
> >
> >
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>___________________________________
>
>Prof. John Antonakis
>Faculty of Management and Economics
>University of Lausanne
>Internef #527
>CH-1015 Lausanne-Dorigny
>Switzerland
>
>Tel: ++41 (0)21 692-3438
>Fax: ++41 (0)21 692-3305
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>http://www.hec.unil.ch/jantonakis
>___________________________________

___________________________________

Prof. John Antonakis
Faculty of Management and Economics
University of Lausanne
Internef #527
CH-1015 Lausanne-Dorigny
Switzerland

Tel: ++41 (0)21 692-3438
Fax: ++41 (0)21 692-3305

http://www.hec.unil.ch/jantonakis
___________________________________