statsmodels/statsmodels — pull request #1253 by josef-pkt (2013-12-18 21:29:31+00:00)
Title: Wls llf fix

adjusted tests and added tests to @bashtage PR #1251 , supersedes now that PR

open problem: rsquared doesn't match, see #1252 (not for this PR, since I don't know how #1252 is supposed to be "fixed")

llf, aic and bic differ now from Stata, see and closes #1170