Text stimulus (chart): Grouped bar chart titled 'Enrollment compared with survey sample'. X-axis categories: General program, Arts program, Career-tech program, Online program. Y-axis percentage scale 0 to 70. Display details: two bars per category: Enrollment percentages 60, 15, 15, 10; Survey sample percentages 35, 20, 35, 10. What is the best concern about the completed survey sample?