MIDDLE SCHOOL TEACHERS' INFORMAL INFERENCES ABOUT DATA DISTRIBUTIONS

This paper describes the informal inferences made by middle school teachers in response to a task involving a comparison of two data sets. Of specific interest were not only the decisions the subjects made about the scenario they were presented with, but also the nature of their distributional reasoning behind their decisions. Results showed that teachers used both centres and spread in their distributional reasoning as they made probabilistic generalizations that often included evidence of contextualization. As teachers begin to examine the aspects of distributional reasoning which they themselves bring to bear in making informal inferences, they can better promote the informal inferences made by engaging their own students in authentic statistical inquiry.