What is relation of fraction of binary stars with spectral class (mass)? For example, how many binary stars are among O,B,A,F,G,K,M stars separately?
The second paragraph of this paper by Kouwenhoven et al. has a great summary:
(Note those references can be found easily on the SAO/NASA ADS here.)
The rest of the paper describes some of the subtleties at work when astronomers combine modeling with observational data.