Improving Vocabulary Mastery of the Seventh Grade Students Through Tree Diagram Technique

The objective of this research is to investigate the effectiveness of tree diagram technique in improving the students\u27 vocabulary mastery. This research employed quasi-experimental research design, consisting of experimental and control group. The population is the seventh grade students and the sample is VIIA and VIIB consisting of 21 students for each. The researcher applied purposive sampling technique in selecting the sample. In collecting the data, the researcher used test (pre-test and post-test) as the research instrument. To analyze the data, the researcher used statistical analysis by applying t-test formula. The result of data analysis shows that the hypothesis of the research is accepted by regarding that the tcounted (4.134) was higher than the ttable (2.021) which the degree of freedom (df) of the table is Nx + Ny – 2 = 21 + 21 – 2 = 40 with the level of significance, 0.05. In conclusion, tree diagram technique can improve the vocabulary mastery of the seventh grade students