Effect of Belief Bias on the Development of Undergraduate Students' Reasoning about Inference

Psychologists have discovered a phenomenon called "Belief Bias" in which subjects rate the strength of arguments based on the believability of the conclusions. This paper reports the results of a small qualitative pilot study of undergraduate students who had previously taken an algebra-based introduction to statistics class. The subjects in this study exhibited a form of Belief Bias when reasoning about statistical inference. In particular, the subjects in this study were more likely to question the experimental design of a study when they did not believe the conclusions reached by the study. While these results are based on a small sample, if replicated, the results have implications for the teaching of statistics. Specifically, when teaching hypothesis testing, statistics instructors should be mindful about the context of example problems used in class, make explicit links between inference to experimental design and actively engage students in discussions of both believability of conclusions and the types of arguments they find convincing.