Supplementary Material: Students' Self-Perceptions in Polya's Problem-Solving Model for Physics and Mathematics

This supplementary document provides supporting material for a mixed-methods study on students’ self-perceptions of Polya’s problem-solving phases in physics and mathematics, conducted with early-semester undergraduate engineering students. It includes the instrument validation process, the original open coding scheme with initial codes, the original questionnaire, and intermediate calculations related to the ANOVA analysis. These materials are provided to ensure transparency, reproducibility, and methodological clarity.