Collect Prefix Command and Ttest results

[Ethan Goode]

Hi all,

In Stata 17 I've been trying to work with the collect command to produce some Latex tables! Currently I use the collect prefix command on the ttest command (paired ttest). Then I use

 return list

to view the stored scalars from the ttest command. I notice that some scalars of interest are not stored. In particular, the table reports the difference between the two sample means, but this difference is not stored. Is there a way to access this scalar so that I can then include it in the collect table, or is there a way I can manually add this scalar to the collect table? I've included the exact code I have, but it is only a couple of lines:

collect: ttest median_family_income, by(diff)
return list
collect layout (colname) (result[mu_1 mu_2])

Thanks!
-- Ethan

[Carlo Lazzaro]

Ethan:
welcome to this forum.
Surely off-target here, but -ttest- is conceived for detecting difference between two means, not medians.
See -qreg- instead.

[Ethan Goode]

Hi Carlo,

Thank you for the warm welcome. The variable name is likely confusing as it is the median family income a census tract. I use the ttest to test the difference between the average median family income in census tracts that are in group 1 vs. group 2.

-- Ethan

[Andrew Musau]

You can store the value in a local.

local diff= r(mu_1)-r(mu_2)
di `diff'

[Bjarte Aagnes]

 collect get r() diff = r(mu_1)-r(mu_2) : ttest price , by(foreign)

.   collect levelsof result

Collection: default
 Dimension: result
    Levels: N_1 N_2 df_t diff level mu_1 mu_2 p p_l p_u sd sd_1 sd_2 se t

[Ethan Goode]

Thanks both Bjarte and Andrew! I went with Bjarte's method.