# RE: st: comparing three gorups

 From "Rajesh Tharyan" <[email protected]> To <[email protected]> Subject RE: st: comparing three gorups Date Sun, 7 Sep 2008 10:08:35 +0100

```Hi,

I suppose I have to say testparm _I*4 and then testparm _I*5
And then compare.

Thanks
rajesh

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Rajesh Tharyan
Sent: 07 September 2008 09:50
To: [email protected]
Subject: RE: st: comparing three gorups

Hi maarten,

Thanks very much.. that is very helpful. One of the variables is highly non
normal but log transformation makes it reasonably close to normal. So I
suppose I could do that.
In the example you have created three groups based on rep78. A mvreg is run
with mpg and trunk as the depvars with dummies for the three groups of
rep78.

The output shows that w.r.t mpg group 4 is more similar to group 3. w.r.t
truck again group 4 is more similar to group 3. The parmest gives me an
overall F. But how I do I interpret that w.r.t to mpg and trunk combines gp
4 is more similar to go 3.

Thanks
rajesh

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Maarten buis
Sent: 07 September 2008 08:03
To: [email protected]
Subject: Re: st: comparing three gorups

--- Rajesh Tharyan <[email protected]> wrote:
> I have 3 groups of companies, each group characterised by 2 variables
> x and y, say groups A, B and c. What is the simplest way to test
> whether A is similar to B or C in terms of these two variables?

The example below will work when x and y are, conditional on your
grouping variable, approximately normally distributed.

*---------- begin example ----------
sysuse auto, clear
recode rep78 1/2=3
xi: mvreg mpg trunk = i.rep78
testparm _I*
*----------- end example -----------

Hope this helps,
Maarten

-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands

Buitenveldertselaan 3 (Metropolitan), room Z434

+31 20 5986715

http://home.fsw.vu.nl/m.buis/
-----------------------------------------

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