Chapter 9 Non Experimental Designs

[@letsmakeitagoodworld]

Hiya im wondering if you can help identify what sort of research design this would be!, If a study has 2 prior established groups- alcoholics and a non alcoholic group. The groups were tested on reaction times. there was no manipulation they both had the same test to compare reaction times. what design is this, i thought maybe ex post factor, but im not certain? thanks