Investigation of 8th grade students informal statistical inferences through statistics-oriented STEM activities

The aim of this study is to obtain information about informal statistical inferences of 8th grade students through statistics-oriented STEM activities. The model of the research is design-based research method. The study group consists of six 8th grade students studying in a middle school in Merkezefendi district of Denizli province. The main activity and the follow-up task of the research were organized in accordance with the model eliciting activities. The data of the research were obtained through task-based interviews, documents and observation. The qualitative data were analyzed by content analysis method within an informal statistical inference framework (Makar ve Rubin, 2018). Findings consist of generalization, use of data as evidence, probabilistic language, consideration of the aggregate and integration of contextual information. The findings of the generalization component of the study show that students form their hypotheses by comparing data for situations in which changes were made to the independent variable, using measures of central tendency, based on its spread, or using the science context. It has been determined that they use different strategies when drawing an estimated distribution based on their hypotheses. In the component of using data as evidence, it was observed that the majority of students made inferences in the context of the problem based on the central tendency of the data they collected. The findings of the probabilistic language component of the research revealed that students used uncertainty expressions when making hypotheses for situations in which changes were made to the independent variable in their experiments. In addition, while none of the students reported certainty in the informal statistical inference they made in the main activity, two students included percentage expressions expressing certainty in the follow-up activity due to the increase in the number of data. In the consideration of the aggregate component, students examine graphs from a holistic perspective, comparing data or measures of central tendency while making inferences in the context of the problem. In the integration of contextual knowledge component, students used their knowledge about the concepts of mass, friction force, potential and kinetic energy in solving the problems presented to them. In this process, the concepts mentioned and their thoughts about their relationships with each other and with other concepts were revealed.On the other hand, the majority of their material design suggestions were created from materials they designed in science courses.