Building a Theory of Graphicacy: How Do Students Read Graphs?

A study examined middle grades students' learning of concepts related to the use and interpretation of graphs. Subjects of the study were 76 sixth-grade students in 3 different mathematics classes in a central North Carolina middle school. The first two parts of the written instrument were administered as both a pretest and a posttest, using line plots and bar graphs; the second two parts, using stem plots and histograms, were administered only as a posttest, since few students have had experience with these graphs. For each question on the tests, the analysis involved categorizing responses in ways that characterized the nature of students' thinking. Results indicated that students: (1) confuse the axes of line plot and histogram type graphs; (2) have problems using intervals of data; (3) use the "middle" of the data to describe what is typical much less frequently than the mode; and (4) seem to find the measures of center, mean and median, not readily identifiable from the graph. Findings revealed that the manner in which questions were posed could influence the categorization of student responses, as could the visual features of the graphs, and that the students' interpretation of the word typical may not be viewed as intended. Further research is suggested to look at both visual and wording effects more systematically. (Includes 6 figures of data and 26 references.) (CR)