stratifying parametric lognormal regression model

[Wumbe Emma]

I wanted to find out how I can stratify a parametric regression model by a variable. So assuming I fit a lognormal distribution on ethnicity: (streg i.ethnicity, dist(lognorm) vce(robust) tr ) but want to stratify this a categorical variable, birthweight, how I would I go about this?

[Rich Goldstein]

I'm a bit confused - if you look at the help file for -streg-, you see that one of the options is "strata(varname)" - doesn't this do what you want? if no, please clarify