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correlation 0.374
4. the significance of
correlational coefficient
XY t
count
= 3.821 t
table 0.05; N=28
= 1.701
t
count
t
table
Rejected
By using SPSS 16 with product moment correlational analysis, the result of computation above shows that the correlation coefficient r between
vocabulary mastery X and reading comprehension Y is 0.600; it is greater than r
table
at significance level 5 for N= 28; 0.374. So, it can be stated that the coefficient of correlation is significant.
Based on the analysis above, it can be stated that the null hypothesis H
o
is rejected and therefore the alternative hypothesis H
a
is accepted. The conclusion is that there is positive correlation between vocabulary mastery X
and reading comprehension Y. Furthermore, based on the interpretation of r value Sugiyono, 2010:184, the value of r for the correlation between
vocabulary mastery and reading comprehension is 0.600 that is included in the interval 0.600-0.79. It means that the correlation between vocabulary mastery
and reading comprehension is strong.
D. The Discussion of the Research Finding
The result of the research shows that there is positive correlation between vocabulary mastery toward reading comprehension.
A positive correlation means that the increase of vocabulary mastery is followed by the increase of reading comprehension. This kind of correlation
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creates an assumption that reading comprehension can be regressed, explained, and predicted from vocabulary mastery.
By considering the result of the hypotheses testing, it can be explained as follows.
The Hypothesis
In the hypothesis testing, it is found the equation of simple linear regression between X
and Y, that is: Ŷ = 35.144 + 0.572X. The equation shows
that X and Y have linear correlation, so that the score of vocabulary mastery can be used to predict the reading comprehension. Based on the significance of
simple linear regression test between X and Y, it is found that H
o
is rejected and H
a
is accepted. Thus, the linear regression between X and Y is significant. Then, based on the statistic analysis by using SPSS 16, it is obtained that
F
observation
= 14.603 F
table
= 4.19; the coefficient of correlation r = 0.600 r
table 28;0.05
= 0.374. So, H
o
is rejected and therefore it means that there is positive correlation between vocabulary mastery and reading comprehension.
One of the predictors of reading comprehension is vocabulary mastery. As stated by Scott 2010, “Vocabulary knowledge is one of the best
predictors of reading comprehension. Among first and second grade students, reading comprehension can be predicted to a large extent by vocabulary.” It
shows that vocabulary mastery plays an important role in reading comprehension. By having large extent of vocabulary, a learner will be easier
to grasp the meaning from the text being read. It means that one needs more vocabularies so that he or she can understand the meaning of the sentence.
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Besides, Chall and Dale in Graves, 2009 add that vocabulary difficulty strongly influences the readibility of text. It is obvious that vocabulary mastery
and reading comprehension are strongly correlated. Based on the explanation above and the result of the hypothesis
testing, it can be concluded that vocabulary mastery contributes to reading comprehension. In other words, there is positive correlation between
vocabulary mastery and reading comprehension. Then, it also means that the improvement of students’ vocabulary mastery will be followed by the
improvement of students’ reading comprehension.
