Evaluating the strength of evidence in noisy data is a critical step in scientific thinking that typically relies on statistics. Students without statistical training will benefit from heuristic models that highlight the logic of statistical analysis. The likelihood associated with various coin-tossing outcomes gives students such a model. There is a point at which a majority of students will doubt the underlying fairness of a coin-tossing game, and that student-generated cutoff can be used as a critical value in a nonparametric analysis of paired data. Following this approach, student lab reports come to more closely model scientific thinking.