# Re: st: re: table for differences in means test

 From "Hugh Colaco" To statalist@hsphsun2.harvard.edu Subject Re: st: re: table for differences in means test Date Sun, 22 Jul 2007 16:49:00 -0400

```Thanks Kit and Ronan. One more thing - how can I include the overall
no of observations and mean (i.e. both groups of variable q2q6) in the
same table? It should look like:-

Variable        N       Mean    N1      Mean1   N2      Mean2   p-value

Right now, I am doing it in two steps and entering the values of N and
Mean manually.

Step 1 - Subsamples N1 and N2

qui {;

noi di "Variable`=char(9)'N1`=char(9)'Mean1`=char(9)'N2`=char(9)'Mean2`=char(9)'p-value";

foreach var of varlist q52-q61 {;
cap ttest `var', by (q2q6);

noi di as text "`var'`=char(9)'" as result %8.0f `r(N_1)' "`=char(9)'"
%8.2f `r(mu_1)' "`=char(9)'" %8.0f `r(N_2)' "`=char(9)'" %8.2f
`r(mu_2)' %8.2f `r(p)';

};
};

Step 2 - Overall sample N (i.e. N1 + N2)

qui {;

noi di "Variable`=char(9)'N`=char(9)'Mean`=char(9)'";

foreach var of varlist q52-q61 {;
cap ttest `var'==0 if q2q6==1 | q2q6==2;

noi di as text "`var'`=char(9)'" as result %8.0f `r(N_1)' "`=char(9)'"
%8.2f `r(mu_1)' "`=char(9)'";

};
};

which gives me the output

for Step 1

Variable        N1      Mean1   N2      Mean2   p-value
q52          117            3.06              14            2.71    0.20
q53          120            3.64              17            3.06    0.01
q54          105            1.34              16            1.69    0.08
q55          106            1.91              13            2.31    0.16
q56          109            3.01              16            2.88    0.60
q57          105            2.21              14            2.57    0.26
q58          106            2.80              16            2.81    0.97
q59          115            3.51              15            2.93    0.01
q60          106            1.58              14            2.14    0.02
q61          108            2.12              13            2.62    0.08

and Step 2

Variable        N       Mean
q52          131            3.02
q53          137            3.57
q54          121            1.39
q55          119            1.95
q56          125            2.99
q57          119            2.25
q58          122            2.80
q59          130            3.45
q60          120            1.65
q61          121            2.17

Hugh

On 7/21/07, Kit Baum <baum@bc.edu> wrote:
```
```Hugh writes

I tried using this code

qui {

noi di "Variable`=char(9)'N1`=char(9)'Mean1`=char(9)'N2`=char
(9)'Mean2`=char(9)'p-value"

foreach var of varlist q52-q61 {
cap ttest `var', by (q2q6)

noi di as text "`var'`=char(9)'" as result  %8.0f `r(count)'
"`=char(9)'" %8.2f `r(mu_1)' "`=char(9)'" %8.2f `r(p)'
}
}

If you do

sysuse auto
ttest price, by(foreign)
return list

you see that r(N_1) and r(N_2) contain the counts in the two
categories. There is no r(count).
You probably want to include both r(mu_1) and r(mu_2) in your display
statement if you want to
see the means of each category.

Kit Baum, Boston College Economics and DIW Berlin
http://ideas.repec.org/e/pba1.html
An Introduction to Modern Econometrics Using Stata:
http://www.stata-press.com/books/imeus.html

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```
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```