Middle school students' thinking about variability in repeated trials: A cross-task comparison

This paper summarizes the thinking of 84 middle school mathematics students' about variability in three stochastics tasks that involve repeated trial. Differences in students' acknowledgement of variability were found, depending on whether the task was from a sampling environment, or a probability environment. Students' tended to neglect variability in the probability environment. We conjecture that the way that probability is normally introduced to students is part of the cause of this phenomenon.