RE: st: t-test command for simple cross-tabs

 From "Nick Cox" To Subject RE: st: t-test command for simple cross-tabs Date Tue, 25 May 2004 21:23:13 +0100

```There were two interesting articles in TAS which may be relevant.

Comparing Two Proportions from the Same Survey.
C.J. Wild; G.A.F. Seber
The American Statistician 47 (Aug. 1993), 178-181.

Difference of Proportions from the Same Survey.
A.J. Scott; G.A.F. Seber
The American Statistician 37 (Nov. 1983), 319-320.

As I recall, however, neither boils down to a t-test.

I was very interested in these papers when I read them,
but never focused on how to do either in Stata. Irrespective
of whether either is the answer to Claudia's question,
I would be happy to learn of Stata implementations.

Nick
n.j.cox@durham.ac.uk

Claudia Solari

> Thank you so much for your response.  It is my understanding that a
> chi-square test can tell me if the relationship between two
> variable is
> significant, lets say region (ne, mw, w, s) and age cateories (19-29,
> 30-34, 35+).  The chi-square refers to whole variables, and
> the t-test is
> based on the categories, such as proportion in a cell (means or
> percentages).  So, I might want to know if there are significant
> differnences in age for those who live in the NE versus the South.
>
> I know of a free software package that calculates my t-tests
> (STATS), but
> I'm not sure how to make STATA do it.   I was unable to reach the url
> that you indicated, so I am not sure if my email is redundant.  If you
> have any further comments, I would love to hear them.

Richard Williams

> > I'm probably showing my ignorance here, but what do you want to do a
> > t-test
> > of, and how would it differ from what the chi-square test
> tells you?  In
> > the special case of 2 X 2 tables, it is possible to do a
> z-test using the
> > -prtest- command; see p. 7 of
> > http://www.nd.edu/~rwilliam/stats1/Categorical-Stata.pdf.  Is that
> > what you
> > want, or do you have something else in mind?  If
> occupational status is a
> > continuous variable, you could of course just use the
> t-test command.

Claudia Solari

> > >I am just trying to find out the command to conduct a
> t-test for a simple
> > >crosstab, such as gender by occupational status. I know
> there is a simple
> > >command for the chi-square test, wihc is just an option
> for the tabulate
> > >command, but I have not found an option for a t-test.

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