Weighted t test

[Laurens Mittertreiner]

Is it possible to ttest a variable weighted by another variable in the dataset? So, to ttest the weighted average. The variable that I want to be tested are several stock betas (variable created by regressions) that have to be weighted by market values (each stock beta has a corresponding stock market value). I read somewhere that it is possible to set it up as a regression problem, but I am not sure how to.

[Rich Goldstein]

as you say, this can be done via - regress-; so, the following two results are the same:

sysuse auto
ttest price, by(foreign)
regress price i.foreign

-regress- allows the use of any kind of weight; see

help regress

I believe, but could be wrong, that you want a two-sample test; if you want a one-sample test, there is a regression for that also