Hello. I am using -ttest- in combination with -bys- to do group mean comparison tests by the variable YEAR. Specifically, the command is...
bys YEAR: ttest REV if inlist(TYPE,1,3), by(TYPE)
My issue is this:
It does the test three separate times, i.e., for each value of YEAR. That is perfect. But, aside from generating three separate t-tests for the difference-in-means, is there a way for me to evaluate the three tests jointly, with a single test statistic? In other words, let's say that for 2 of the 3 years, I can reject the null. But, I cannot reject the null for the 3rd year. Can I test the joint hypothesis that I can reject the null across the 3 years?
Thanks. Lloyd.
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/