A Comparative Overview of

Although statistical variation does not receive detailed attention in mathematics curriculum documents, students actually experience variation every day of their lives. Among other varying phenomena, the weather provides a topic of discussion for young and old. From early childhood, teachers are known to put up weather calendar charts recording the weather for weeks at a time. This study uses the weather context to explore students ’ development of intuitive ideas of variation from the third to the ninth grade. Three aspects of understanding these intuitions associated with variation are explored in individual video taped interviews with 66 students: explanations, suggestions of data, and graphing. The development of these three aspects across grades is explored, as well as the associations among them. Fifty-eight of the students also answered a general question on the definition of variation and variable and these responses are discussed and compared with responses to the weather task. The interview protocol may prove useful for teachers, particularly with younger children, to appreciate students ’ developing understanding of variation and provide starting points for classroom work of a more specific nature, either with respect to weather or other contextual topics. Literature Review Probably the two most significant background contributions to the interest in school students ’ understanding of variation have come from Moore (1990) and Wild and Pfannkuch (1999). Their discussions put variation and variability firmly on the agenda as part of statistical thinking and reasoning. They have been followed recently by Konold and Pollatsek (2002), who address the dilemma of thinking about data as a combination of signal and noise. Calls for research specifically on school students ’ understanding o