Within the limited field of research on teachers' probabilistic knowledge, incorrect, inconsistent and even inexplicable responses to probabilistic tasks are most often accounted for by utilizing theories, frameworks and models, which are based upon heuristic and informal reasoning. More recently, the emergence of new research based upon informal logical fallacies has been proving effective in accounting for certain normatively incorrect responses to probabilistic tasks. This article contributes to this emerging area of research by demonstrating how a particular informal logical fallacy, known as "an appeal to ignorance," can be used to account for a specific set of normatively incorrect responses to a novel probabilistic task, which were provided by prospective elementary and secondary mathematics teachers. [For the complete proceedings, see ED584829.]