The purpose of this study was to describe students' problem solving performance when they make conjectures to comprehend three statistics terms. Teachers are key figures in changing the ways in which mathematics is taught and learned in schools. Mathematics teachers are supposed to design meaningful tasks to motivate students' interest and to enhance students' communication and reasoning. Within various contexts, if meaningful tasks are designed for students to work on, then students should benefit more from those contexts of problem solving. For example, in this unit for learning three statistics terms, i.e., median, mode and range, the authors provided opportunities for students to conjecture, verify, and modify their rules rather than directly telling them the rules to find those three statistics terms. Such a learning process might result in better student performance. (Contains 6 figures.)