Abstrak
ABSTRACT Nisa Khairani, 2318074. The Effect of Using Possible Sentences Strategy on Students’ Vocabulary Mastery at the 10th Grade Of MAS TI Tarusan Kamangi, A Thesis, State Islamic University of Sjech M Djamil Djambek Bukittinggi, 2025. This study aimed to investigate the effect of the Possible Sentences strategy on the vocabulary mastery of tenth-grade students at MAS TI Tarusan Kamang. Preliminary observations and interviews revealed key problems: the teacher's reliance on conventional teaching methods leading to student boredom, and students' low vocabulary mastery levels, evidenced by test scores below the minimum passing criteria (KKM). This research employ a pre-experimental design using a One Group Pretest-Posttest design was utilized. The entire population of tenth-grade students (N=20) served as the sample using total sampling. Data were collected through pre-tests and post-tests, which were analyzed using descriptive statistics and the non-parametric Wilcoxon Signed-Ranks test, as the data did not meet the normality assumption, despite being homogenous. The findings indicated a statistically significant improvement in students' vocabulary mastery after implementing the Possible Sentences strategy. The mean post-test score (72.40, SD=9.96) was significantly higher than the mean pre-test score (59.75, SD=8.57), with a Wilcoxon test result of Z=-3.737 and p=0.000 (0.05). The calculated effect size showed a 21.17% increase, demonstrating that the strategy had a moderate to large positive impact on students' vocabulary mastery. Therefore, the Possible Sentences strategy is effective in enhancing vocabulary learning in this context. Key Terms: Possible Sentences Strategy, Vocabulary Mastery