Frequentist: H1: answer ~ upset + error H0: answer ~ error I find many people have trouble expressing a reasonable hypothesis / null-hypothesis pair.

Frequentist: H1: answer ~ upset + error H0: answer ~ error I find many people have trouble expressing a reasonable hypothesis / null-hypothesis pair. In fact, I'd bet that a good chunk of folks would try to make "upset" be the dependent variable in the phone call scenario.