I came across this answer on looking at a question in the sidebar. The answer was accepted and upvoted 6 times. There is a linked study, but it is a counter example (it is cited as a demonstration of a case where the answer doesn't hold), and even so, it (the study) doesn't directly address the question or the statements made in the answer.
I've noticed a banner on some questions to the effect that an answer is not supported by sources and can be challenged. How would I request that banner for an unsourced answer?