TY - JOUR TI - Undergraduates' (mis) understanding of percentages DO - https://doi.org/doi:10.7282/T3KD1Z0G PY - 2010 AB - Children and adults alike continue to have difficulty with rational numbers, and, as shown in this study, percentages. Adult undergraduate students (N = 27) completed an untimed open-ended study that had a pretest-training-posttest design. Questions in the pretest and posttest focused on percent increases and decreases (e.g., The price x was increased by 20%). They were formatted in one of three representations: decimal, fraction, or bar graph. Subjects were randomly assigned to one of two training groups (decimal or fraction) that involved guiding them through the conceptual and procedural component processes that contribute to the solutions to problems within a given representation (i.e., decimal or fraction). Additional questions were asked in the pretest and posttest pertaining to successive percent increases and decreases. Overall, students performed best on bar graph representations. While decimal training had no effect on performance, fraction training improved performance from pretest to posttest in every category (decimal, fraction and bar graph). Students who had not yet taken Calculus were shown to have benefited more from the fraction training than those students who had taken that course. In contrast, prior math experience did not seem to have any effect on those questions dealing with two percent changes within one problem; less than 25% of these types of problems were answered correctly by the undergraduate students. KW - Psychology KW - Numbers, Rational KW - Algebraic fields KW - Mathematics--Study and teaching (Secondary) KW - Undergraduates--Examinations LA - eng ER -