Abstract
The objectives of this study are: 1) to describe the vocabulary mastery of grade X students of Ridho Zahra Besitang Private Vocational School, 2) to describe the skills of writing observation report texts of grade X students of Ridho Zahra Besitang Private Vocational School, 3) to describe whether or not there is a correlation between vocabulary mastery and writing skills of observation report texts of grade X students of Ridho Zahra Besitang Private Vocational School. This research was conducted in the even semester of the 2023/2024 academic year. The population of this study was all grade X students of Ridho Zahra Besitang Private Vocational School. The sampling technique was carried out by proportional random sampling with a sample size of 56 students. The research method used was the Quantitative method. The results of hypothesis testing using the product moment correlation formula show a sig level of 0.395 with low correlation, while rtable at a sig level of 5% and N = 56 is 0.263. The results of the analysis show that the rcount value is greater than rtable (0.395>0.263) Ha is accepted and H0 is rejected. This means that there is a positive and significant relationship between vocabulary mastery and the writing skills of observation report texts of students at Ridho Zahra Private Vocational School, Besitang. If students' vocabulary mastery is low, then their writing skills of observation report texts are also low. The vocabulary mastery of class X students at Ridho Zahra Private Vocational School, Besitang District obtained an average value of 62.7 with a fairly good category. The writing skills of observation report texts of class X students at Ridho Zahra Private Vocational School, Besitang District obtained an average value of 61.2 with a fairly good category.