Hi, thanks for the suggestion for the different (tech) option. I tried them but it doesn't generate stable results, which I mean too big to be normal or couldn't concave to the point.
Instead of cutting some outliers of my data or using more advanced software, is there any other possible methods in STATA to solve it?
Thanks a lot.
Shaling
*
* 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/