Confidence Means What?!?: Lexical Ambiguity in the Interpretation of Confidence Intervals

Associations of Statistics and Psychology recommend reporting interval estimates, such as confidence intervals, when communicating data-based results. Previous research in statistics education, however, has identified the word confidence as having lexical ambiguity for students learning statistics. This study investigates the nature of this ambiguity with the interpretation of confidence intervals. Analysis of transcripts from task-based interviews revealed four themes, (a) sureness/belief, (b) confident in outcome, (c) confusion of chance/probability, and (d) equivalence of chance/probability, none aligned with the statistical concept definition when the word is applied to confidence intervals. The results of this study identify confusion between the words confident, sureness, probability, and chance as areas for further research as well as classroom attention. Researchers should continue to investigate these issues while instructors exploit these ambiguities.