Making students understand the uncertainty of measurements is an important pedagogical goal of university physics experiments． In the introductory college physics laboratory course，two versions of the teaching approach are prepared:namely，with and without graphical presentation of measurement data．At the end of the course，students were tested to investigate whether the graphical presentation of data improves students’ understanding of uncertainty． The results showed that students in classes with graphical representations scored higher than students in classes without graphical representations． Graphical representations help visualize data and reduce the cognitive load on students when performing analysis of measurement data，and therefore should be actively promoted for use in teaching．