The assessment was administered to 105 undergraduates at the University of Minnesota currently enrolled in an introductory statistics course that utilized the Sampling SIM software. At the start of the second half of the course, these students used Sampling SIM to complete an activity on sampling distributions, and then took the diagnostic test at the start of the following class session. Nine statistics majors at Cal Poly who were enrolled in a senior-level capstone course but had never interacted with Sampling SIM also completed the diagnostic test. Altogether, the 114 students showed substantial variation in their responses to the questions. With respect to the two graph-based problems (items 4 and 5; see Appendix), only 10% made correct choices for both graphs in both problems, and another 22% made correct choices for both graphs in only one of the problems. Many students (47%) made choices that were not correct, but indicated an understanding that sampling variability decreases as sample size increases. Of the remaining students, 19% made choices for at least one problem that suggested a belief that sampling variability increases with increases in sample size, and two of the students chose the same graph for both sample sizes.