From the table of significance see appendix 11, it is obtained that t
table
of 1 and d
f
= 42 is 2.69807. It indicates that t
o
is higher than t
table
, in which 3.210 2.698. Therefore, the alternative hypothesis H
a
is accepted. In other words, there is a significant relationship between vocabulary mastery and writing achievement.
According to the result of the calculation of Pearson Product Moment above, the value of correlation coefficient r
o
is 0.444. To interpret the gravity of 0.444, the table of “r” product moment shows that the correlation value is in between
0.40 —0.59, or moderate level. The medium correlation means that the
relationship tends to the positive value and there is no negative relationship. The table of “r” interpretation was adopted from Jonathan Sarwono’s theory.
Table 4.9 The Interpretation of Correlation Coefficient
Coefficient Interval Degrees of Correlation
0.00 —0.19
Very weaklow 0.20
—0.39 Weaklow
0.40 —0.59
Mediummoderate
0.60 —0.79
Strong 0.80
—1.00 Very Strong
B. Discussion
Based on the data description of vocabulary mastery, it is found that the seventh semester students of Department of English Education in academic year
20162017 commonly have good vocabulary mastery, which is indicated by the result of the average score found is 74.27 and the mode score is 76.00. However,
although the students are considered to have good vocabulary mastery, there are still some students who have limited knowledge of vocabulary. From the data of
vocabulary mastery score, it is shown that almost a half of the total sample obtained score under the mean score. Therefore, some students of Department of
English Education should learn more about vocabulary.
Meanwhile, from the data description of writing achievement, the score is slightly below the vocabulary mastery, but good still. It can be seen from the
average score of writing achievement which is 74.00, while the mode is 70. In addition, according to the data description of writing achievement, it can be seen
that almost half of the total sample obtain score under the mean score. Therefore, besides learning more about vocabulary, students of Department of English
Education also should learn and practice writing more. In addition, the findings reveal that there is a significant relationship
between vocabulary mastery and writing achievement. It is indicated that the value of correlation coefficient r
xy
is higher than the score of r table r
t
. In the case, the correlation coefficient is 0.444, and the value is compared with r
t
at the level of significance 0.01 obtained respectively 0.384, in which r
o
= 0.444 r
t
= 0.384. Similarly, based on the calculation of t
count
above, the value of t
count
is higher than the value of t
table
at the level of significance 0.01, in which t
count
= 3.210 t
table
= 2.698. Since, r
o
and t
count
are higher than r
t
and t
table
, it means that the alternative hypothesis H
a
is accepted and null hypothesis H
o
is rejected. In other words, there is a significant relationship between vocabulary mastery and
writing achievement of the seventh semester students of Department of English Education of Syarif Hidayatullah State Islamic University of Jakarta in academic
year 20162017. This result supports the relationship between vocabulary and writing.
1
In addition, regarding to the relationship between vocabulary knowledge and writing performance, Saadian and Bagheri revealed in their study that
vocabulary knowledge contributed to students’ writing performance.
2
Therefore, students who master vocabulary may achieve better writing achievement.
Additionally, based on the determination of coefficient r
2
= 0.197 obtained, vocabulary mastery is considered to have contribution of 19.7 towards writing
achievement. In other words, the writing achievement of the seventh semester
1
Brian Richard ed., Vocabulary Studies in First and Second Language Acquisition, New York: Palgrave McMillan, 2009, p. 40.
2
Hamideh Saadian and Mohammad Sadegh Bahgeri, The Relationship between Grammar and Vocabulary Knowledge and Iranian EFL Learners’ Writing Performance TOEFL PBT
Essay, International Journal of Language Learning and Applied Linguistics World, Vol. 7 1, 2014, p. 12.
students of Department of English Education of Syarif Hidayatullah State Islamic University of Jakarta in academic year 20162017 is 19.7 influenced by their
vocabulary mastery and there is 80.3 as the remains. The remains indicate that there are other factors which influence their writing achievement. As Hayes says
that there are several factors influencing writing such as motivation, cognitive process, and long term memory which includes topic knowledge, audience
knowledge, linguistic knowledge, and genre knowledge.
3
Hence the factors mentioned above can be the 80.3 of the remained influences of writing
achievement. To sum up, the data interpretation shows a finding that vocabulary mastery
and writing achievement correlate each other. Vocabulary mastery gives contribution r
o
0.444 to writing achievement. It means that the better students master vocabulary, the better stud
ents’ writing achievement.
C. Research Limitation
