Exporting results after t-test, posthandle

[Chinmay Sharma]

Hi All,

I have data which resembles the following:

* Example generated by -dataex-. To install: ssc install dataex
clear
input double(group value) str1 action str7 group_description str9 country
1  23 "x" "Group A" "Country X"
1 322 "x" "Group A" "Country X"
1   3 "y" "Group A" "Country X"
1  12 "y" "Group A" "Country X"
2  32 "x" "Group B" "Country Y"
2  12 "x" "Group B" "Country Y"
2  32 "y" "Group B" "Country Y"
2  12 "y" "Group B" "Country Y"
end

Here, I have information on variable value, by group for different actions x and y. Moreover, in addition to the numeric group identifier, I have two further variables which vary only across groups (group_description and country). I wish to run a t-test (unequal variances) of equality of values by action within group and then save the results in a separate dta file. The command for the test would be:

by group, sort: ttest value, by(action) unequal

The postfile class of commands is apt to then export this data. Not only do I wish to export the t-test and the associated p-value, I also want to describe the group, group_description and the country pertaining to that t-test (I have hundreds of such tests)

postfile handle str7 (group_description) str9 (country) double group float(t_stat p_value) using ttest_results, replace
by group, sort: ttest value, by(action) unequal
post handle ("country") ("group_description")  ("group")  (`r(t)') (`r(p)')
postclose handle

Unfortunately, a) the syntax returns an error and b) even with some contrivance when I get output, it is simply for the first group only. Any guidance on this is much appreciated!!


Best,
CS