The study describes levels of thinking in regard to the design of statistical studies. Clinical interviews were conducted with 15 students who were enrolled in high school or were recent high school graduates, and who represented a range of mathematical backgrounds. During the clinical interview sessions students were asked how they would go about designing studies to answer several different quantifiable questions. Several levels of sophistication were identified in their responses, and are discussed in terms of the Biggs and Collis (1982, 1991) cognitive model. (Contains 4 tables and 2 figures.)