Testing a difference between means is an utterly standard test and can
be found easily even by clicking on Statistics in the menu and
following prompts. The command is -ttest-.
You need a systematic search strategy, not a random one. Whatever
search led you to suppose that you should be using -outreg2- (SSC)
here was ill-advised. I suggest starting by just browsing the menus or
reading a basic introduction to Stata.
http://www.stata.com/bookstore/books-on-stata/ gives details of several books.
Statalist is not deliberately hostile or unfriendly to beginning
users, but there is a strong expectation that any question follows a
serious effort to use resources readily available.
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/faqs/resources/statalist-faq/
* http://www.ats.ucla.edu/stat/stata/
