This thesis examined middle school students' current understanding of variability using a constructed response item assessment question. Variability is an essential concept in the teaching and learning of statistics. However, many students have difficulty with the concept of variability especially when constructing boxplots. Using a framework…

Data analysis problems, particularly involving the likelihood of obtaining visually ambiguous graphs, pose a barrier to efforts to promote increased use of single-case evaluation by practitioners. Uses findings from an evaluation of a cognitive-behavioral intervention with adolescent sex offenders to illustrate data analysis problems. (JPS)