Development of “galton sriwijaya board” teaching aid to support students’ conceptual understanding of normal distribution

This study aims to develop the “Galton Sriwijaya Board” teaching aid to support students’ conceptual understanding of the normal distribution. The background of this research is the difficulty students experience in understanding abstract statistical concepts, particularly the normal distribution and the central limit theorem, when learning is limited to theoretical explanations. This study employed a design research approach based on Tessmer’s formative evaluation model, comprising preliminary, self-evaluation, expert review, one-to-one, and small-group stages. The participants were first-semester students of Mathematics Education selected through purposive sampling. Data were collected through students’ LKPD responses to analyze conceptual understanding, observations, and interviews to identify students’ learning processes and difficulties, and practicality questionnaires to evaluate the usability of the developed teaching aid. Students’ conceptual understanding was analyzed descriptively using two indicators: interpreting experimental results and generalizing the characteristics of a normal distribution. The results show that the developed teaching aid was validated by two lecturers in the Mathematics Education Study Program who teach Mathematical Statistics, and was categorized as practical based on student responses. In addition, students were able to interpret the results of the Galton Sriwijaya Board experiment and identify the formation of a bell-shaped distribution pattern from repeated random trials. The findings indicate that the “Galton Sriwijaya Board” is valid and practical and provides opportunities for students to construct their understanding of normal distribution through hands-on learning activities. The study suggests that the teaching aid has the potential to be implemented in broader learning contexts and further developed into digital-based learning media.