I perform an independent samples t-test on data that have been simulated to correspond to an actual study done by Brody et al. (2004), which tested the hypothesis that individuals who do not smoke would have relatively larger frontal lobes than individuals who do smoke.
Something I didn't mention in the video is relevant to causality. Despite the fact that the Brody et al. (2004) investigation found that smokers have relatively smaller frontal lobes than non-smokers, one does not have a basis to infer causality in this case.