Past studies have documented some pre-service teachers’ (PSTs) difficulties in reasoning about sampling variability. This study adds to the body of literature by investigating the ideas that PSTs employ in reasoning about sampling variability, and by conjecturing what is behind the difficulties especially during the contextuality episodes. This issue was studied in the context of a content course on statistics and probability for elementary and middle grade PSTs at a Midwestern American university. An analysis of a PST’s video and screen records of a task-based interview was guided by techniques of knowledge analysis (diSessa et al., 2016), and focused on two clear contextuality episodes that have caused disequilibrium in the PST’s knowledge system. The analysis described at a moment-by-moment level the cognitive dynamics of the transitions that occurred in the PST’s knowledge system and highlighted some of the difficulties that arise from the activation of less-productive knowledge elements over others. The significance of this study is in its use for the techniques of knowledge analysis from the field of cognitive science to provide a fine-grained description of PSTs’ difficulties in reasoning about sampling variability that went beyond the traditional description of these difficulties as misconceptions.

过去的研究记录了一些职前教师 (PST) 在推理抽样变异性方面的困难。这项研究通过调查 PST 在对抽样变异性进行推理时所采用的想法，以及通过推测困难背后的原因，尤其是在上下文事件中，增加了文献的内容。这个问题是在美国中西部大学的小学和中学 PST 统计和概率内容课程的背景下研究的。对 PST 视频和基于任务的面试的屏幕记录的分析以知识分析技术为指导（diSessa 等人，2016 年），并重点关注导致 PST 知识系统不平衡的两个明确的背景事件。该分析逐时描述了 PST 知识系统中发生的转变的认知动态，并强调了由于激活效率较低的知识元素而不是其他知识元素而产生的一些困难。这项研究的意义在于，它使用了认知科学领域的知识分析技术，对 PST 在推理抽样变异性方面的困难进行了细粒度的描述，这些困难超出了将这些困难视为误解的传统描述。