3.10 Statistical Design
3.10.1 t-Test Statistical Analysis of the Pre-test and Posttest of the
Experimental Group
To determine the significance of the result study, I would like to apply a statistical design of Arikunto that was by using t
test
formula as below:
� =
�� √
∑� � � �−
in which, t
= t
test
Md = mean difference of pre-test and post-test
X
d
= deviation of each subject d-Md ∑X
2 d
= sum of deviation square N
= number of subject Arikunto, 2006:307
The result of t
test
calculation then would be compared to the value of t
table
. This study will be signed as significant if the value of t
test
is higher than t
table.
3.10.2 t-Test Statistical Analysis of the Pre-test and Posttest between Experimental Group and Control Group
After the data was obtained, the next step was analysing the data. It was done by calculating the mean and variance of pre-test and post-test of the experimental
group and the control group. Then it was continued by calculating the t-test to see the significant difference between the two means.
To calculate the mean of pre-test and post-test of students in the experimental and control group can be computed by dividing the sum of all scores
by the number of scores. The following formula can be used:
M
=
∑�
where: M : mean
∑ : sum of X : scores in a distribution
N : number of scores Best, 1981:225
To calculate the variance, the following raw score method can be computed:
� = ∑�
� − 1 Ary, Jacobs, and Sorensen, 2010:117
where: S
2
: variance ∑x
2
: sum of the deviation of each score from the mean X - X squared N
: number of cases
The last, to calculate the significant difference between the two means, the following t-test formula can be done Best, 1981:270:
t
=
� −�2 √
� �
+
� �
where: M
1
: mean of experimental sample M
2
: mean of control sample N
1
: number of cases in experimental sample N
2
: number of cases in control sample �
2
: variance of experimental sample � : variance of control sample
The result of t
test
calculation then would be compared to the value of t
table
. This study will be signed as significant if the value of t
test
is higher than t
table
.
40
CHAPTER IV RESULT AND DISCUSSION
This chapter deals with the result of pre-test, the implementation of the experiment, the effectiveness of subtitled English songs to improve the
vocabulary mastery, and the last is discussion.
4.1 Result of Pre-Test
This research was followed by 32 students of class VIII G SMP Negeri 39 Semarang as the experimental group and 32 students of class VIII H SMP Negeri
39 Semarang as the control group. There were 30 questions in matching tasks format in 45 minutes see Appendix 16.
The result of pre-test in experimental and control group could be seen in the table below:
Table 4.1 Pre-Test Scores of Experimental Group and Control Group
Number Experimental Group
Control Group Students’
Code Pre-Test
Scores Students’
Code Pre-Test
Scores
1
E-01 70.0
C-01 73.3
2
E-02 66.7
C-02 50.0
3
E-03 66.7
C-03 73.3
4
E-04 63.3
C-04 63.3
5
E-05 70.0
C-05 73.3
6
E-06 70.0
C-06 73.3
7
E-07 73.3
C-07 76.7
8
E-08 73.3
C-08 70.0
9
E-09 66.7
C-09 73.3
10
E-10 63.3
C-10 73.3
11
E-11 66.7
C-11 60.0
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