A fictional banquet cohort

A complete guest list is available after a fictional banquet. Sixty guests ate a cold dish and forty did not. Forty-eight of the sixty exposed guests became ill, compared with four of the forty unexposed guests. Interviews used the same illness definition and observation period for both groups. Other dishes and shared activities are still being investigated, and no organism has been established. The initial briefing asks for both a proportional and an absolute comparison. A colleague proposes stating that removing this dish would certainly have prevented every excess case. The team must instead separate the supplied arithmetic from the causal conclusion and explain what further evidence would strengthen or weaken the hypothesis.