Abstract

• The main purpose of the study was to study the effect of mastery learning strategy on students’ mathematics achievement at the middle school level. Mixed-method, QUAN-Qual model was used to investigate the effect of mastery learning strategy. For quantitative research method, an experimental study was carried out to compare the students’ achievement between experimental and control group. The design used in the study was one of the true experimental designs, viz, posttest only control group design. The instrument used in the study was a posttest. Two sample schools, No. (4) BEHS Kamayut and No. (2) BEMS Yankin were selected by a simple random sampling method. The subjects were (60) Grade Eight students from each school. There were two experimental groups and two control groups. The students from experimental groups were taught by using mastery learning strategy and the students from control groups were taught by using formal instruction. After the treatment, the posttest was administered to two groups. The independent samples t-test was used to compare the differences between two groups. The results showed that there were significant differences between two groups in No. (4) BEHS Kamayut (t = 3.02, p < .01) and No. (2) BEMS Yankin (t = 4.72, p < .001). For qualitative research method, the students in the experimental groups from two selected schools were given a questionnaire. The questionnaire consists of 18 items. 15 items of these are coded with five-point Likert-scale and 3 items are open-ended questions. The results showed that the students had positive attitude towards learning, retention of learned materials and involvement in instructional activities. Thus mastery learning strategy had positively contributed to the improvement of mathematics teaching and learning at the middle school level.