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| From | Richard Williams <Williams.NDA@comcast.net> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | Re: st: Stata 11 - Factor variables in a regression command |
| Date | Sat, 01 May 2010 10:58:45 -0500 |
At 12:27 AM 5/1/2010, Ricardo Basurto-Dávila wrote:
I am having trouble understanding the difference between a regression that uses a cross operator (#) and one that uses a cross factorial operator (##). For example, this is the output I get from running two different regressions:
FYI, here is how the manual explains it. If you have Stata 11 you should have the manual in PDF form; see section 11.4.3 of the User Guide.
i.group#i.sex indicators for each combination of levels of group and sex, a two-way interaction
group#sex same as i.group#i.sex group##sex same as i.group i.sex group#sex ------------------------------------------- Richard Williams, Notre Dame Dept of Sociology OFFICE: (574)631-6668, (574)631-6463 HOME: (574)289-5227 EMAIL: Richard.A.Williams.5@ND.Edu WWW: http://www.nd.edu/~rwilliam * * 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/