st: LR test

[j139688 <M.Touny@uea.ac.uk>]

I am estimating a cost function of some plants in three industries over six 
years. I would like to test which is the appropriate model to estimate the 
cost function: using one model for all plants or using three model one for 
each industry (three cost functions). Can I use LR test to do that?

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/