This paper presents a practical laboratory approach on polymer melt flow rate and stress-strain testing to teach undergraduate students how to measure important properties of molten and solid plastics. They may learn how to obtain parameters that are important for: quality control; processing; engineering design on polymer and petrochemical industries; and even in materials selection for engineering applications. Starting from a database obtained from this traditional practice, statistical tools for data analysis were applied. Four different grades of commercial polypropylene were studied, and the 95 % confidence intervals of different parameters were compared with the suppliers’ catalogue data. This pedagogical approach aims to add a statistical point of view to laboratory experiments and to complement the learning.