Exploring informal inferential reasoning: The case of comparing two data sets problem

Abstract

Informal inferential reasoning as part of statistical reasoning is extremely important in learning. However, this reasoning has not been widely studied in Indonesia. This article explores informal inferential reasoning of students in solving comparing two data sets problem. This qualitative research was involved 118 junior high school students in Mataram West Nusa Tenggara. Instrument in this study is Assessment of Informal Inferential Reasoning (AIIR) which was modified and validated by mathematics and mathematics education experts. Student responses are classified based hierarchical cognitive framework. The findings showed that the existing levels was still relevant for the students of junior high school in Mataram. However, there were subjects which could not be classified in the levelling. The characteristic reasoning of the subjects are tends to ignore the variability and distribution aspects of the data in making predictions, but they can indicate significant value differences between two groups of data. They encountered an error in certain aspects, but they are able to produce an almost right conclusions. This study recommends the need for a new levelling to assess informal inferential reasoning of junior high school students by considering the ability of local and global view of data.