The Stata-manual entry on [R] "ttest - Mean comparison tests" (p.486)
states that Student's t-test for the equality of means can be
replicated by aid of a simple linear regression if the two groups'
variances are assumed to be unknown but identical.
I would highly appreciate if anyone could give me a reference with a
formal proof of this relationship. Thanks a lot in advance.
Gosh - hard to think of a published paper that shows this. You will
find it demonstrated in many introductory textbooks. My favourite is