Abstract. This article describes the case study on postgraduate students by using descriptive method. A problem is designed to facilitate the reasoning in the topic of ChiSquare test. The problem was given to two male students with different ages to investigate the gesture pattern and it will be related to their reasoning process. The indicators in reasoning problem can obtain the conclusion of analogy and generalization, and arrange the conjectures. This study refers to some questions-whether unique gesture is for every individual or to identify the pattern of the gesture used by the students with different ages. Reasoning problem was employed to collect the data. Two students were asked to collaborate to reason the problem. The discussion process recorded in using video tape to observe the gestures. The video recorded are explained clearly in this writing. Prosodic cues such as time, conversation text, gesture that appears, might help in understanding the gesture. The purpose of this study is to investigate whether different ages influences the maturity in collaboration observed from gesture perspective. The finding of this study shows that age is not a primary factor that influences the gesture in that reasoning process. In this case, adult gesture or gesture performed by order student does not show that he achieves, maintains, and focuses on the problem earlier on. Adult gesture also does not strengthen and expand the meaning if the student's words or the language used in reasoning is not familiar for younger student. Adult gesture also does not affect cognitive uncertainty in mathematics reasoning. The future research is suggested to take more samples to find the consistency from that statement.
IntroductionThe gesture is a movement towards the body that person does in understanding problems. According to Alibali and DiRusso [1], the functions of gesture can help children to an understanding of numbers to others. In other words, the gesture may help children to pass on their knowledge to the respondent. According to Reynolds and Robert [2], the students make a gesture of collaborating is a source of diagnosis or as information for teachers. This research makes a study of two graduate students gestures collaborate in conducting mathematical reasoning with the statistical material. The three functions of gesture that is: first, the gesture is used to achieve, support, and return the focus to the problems. Second, gesture strengthens and expands the meaning of the word if the student or the language used in problemsolving is not familiar. Third, it is possible in some circumstances, the gesture is an index of an uncertainty level cognitive that replaces the understanding (the changes cognitive). Reynold and Robert [2] see three of these functions on students who collaborate in solving problems of graph speed time and graphical representation of a bus trip. This research addresses the different perspectives, by observing the changes of understanding about what and how an understanding of the changes that occur...