Calc - Statistics - Regression feature was introduced in version 5.1 but has no help page https://wiki.documentfoundation.org/ReleaseNotes/5.1#Calc Commit is http://goo.gl/sPGpEH
I agree, so setting to NEW.
Olivier Hallot committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/help/commit/?id=df2eefa2ce5e5db43df453ba1c2fb52abb88e08e tdf#96868 Help page for data statistics regression