By "fishing expedition" I mean a statistical exercise to describe correlation of a sample's characteristics as if determinative or causative pathogen per se. In the context of this article the expert proposes only retrospective survey of influenza-related deaths to incidence of decendents' obesity. Would it be erroneous or correct if readers infer then that

(a) obesity is a requisite condition of influenza?
(b) influenza is a requisite condition of obesity?
(c) obesity is a requisite of influenza-related death?
(d) none of the above

Otherwise, to what hypothesis and what dataset do you refer?

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