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Re: st: variable not found?
From
Yuval Arbel <[email protected]>
To
[email protected]
Subject
Re: st: variable not found?
Date
Mon, 24 Oct 2011 11:54:06 +0200
Paul,
It seems the purpose of this exercise is to show you that running a
regression on a dummy variable GROUP is an elegant way to find whether
the difference of means between the groups is significant or not.
I ran below the mvreg based on the data you gave. Note, for example,
that while the motivation for GROUP=1 decreases by 7.428 points, this
coeffiecient is insignificant (t-value of -0.62). It implies that
statisticallty there are no motivation differences between the two
groups. On the other hand, the motivation for GROUP=1 is lower by
7.428 points
In other words, the test
. mvreg motiv aspire algebra geom = group
Equation Obs Parms RMSE "R-sq" F P
----------------------------------------------------------------------
motiv 8 2 16.44815 0.0599 .3823938 0.5591
aspire 8 2 12.11901 0.0090 .0543859 0.8234
algebra 8 2 13.90122 0.1842 1.354984 0.2886
geom 8 2 11.11769 0.1715 1.241692 0.3078
------------------------------------------------------------------------------
| Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
motiv |
group | -7.428001 12.01203 -0.62 0.559 -36.82039 21.96439
_cons | 55.73 9.496346 5.87 0.001 32.49328 78.96672
-------------+----------------------------------------------------------------
aspire |
group | -2.063999 8.850472 -0.23 0.823 -23.72032 19.59233
_cons | 73.02 6.996913 10.44 0.000 55.89917 90.14083
-------------+----------------------------------------------------------------
algebra |
group | -11.81733 10.15202 -1.16 0.289 -36.65842 13.02376
_cons | 62.40333 8.025874 7.78 0.000 42.76473 82.04194
-------------+----------------------------------------------------------------
geom |
group | -9.047335 8.11921 -1.11 0.308 -28.91433 10.81966
_cons | 78.57333 6.418799 12.24 0.000 62.8671 94.27957
------------------------------------------------------------------------------
On Mon, Oct 24, 2011 at 3:53 AM, Paul Burkander <[email protected]> wrote:
> Hi all,
>
> I'm trying to help my wife do some stata homework, and we've run into
> some odd behavior.
>
> Below is a sample of the data. She's supposed to do a manova of
> MOTIV,ASPIRE,ALGEBRA,GEOM, on GROUP , then mvreg, then test the
> restriction that the coefficients on GROUP are zero in all four
> equations. After doing the manova and mvreg, we typed test GROUP, but
> receive the error message "GROUP not found."
>
> Any ideas? Perhaps we're doing something dumb? She entered the data
> by pasting into the data editor. We're using Stata 11 SE and I just
> did a full update.
>
> Thanks, Paul
>
> MOTIV,ASPIRE,ALGEBRA,GEOM,GROUP
> 74.31,78.57,68.59,78.57,1
> 27.15,61.91,37.15,71.43,1
> 64.31,90.48,67.16,83.34,1
> 40.01,64.29,48.59,59.53,1
> 35.73,59.53,31.44,54.76,1
> 55.73,83.34,60.02,85.72,0
> 52.87,64.29,62.88,69.05,0
> 58.59,71.43,64.31,80.95,0
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
--
Dr. Yuval Arbel
School of Business
Carmel Academic Center
4 Shaar Palmer Street, Haifa, Israel
e-mail: [email protected]
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/