b. Normality of the Controlled Class
The hypothesis can be seen as follows: H
o
: The data of Y is normally distributed. H
a
: The data of Y is not normally distributed. 1.
Normality of the Pre-test
s
2 =
Σ f n
− [
Σ f n
]
=
− [ ]
=
3815.93 −[ . ]
=
3815.93 −
.
=
.
SD = √
. = 12.33
x ̅= 60.53 T
table
= 0.161 T
max
= 0.116 The result showed that T
max
T
table
0.116 0.161. It can be concluded that in the significant degree of 0.05, H
o
is accepted. It means that the data is normally distributed.
2 2
2. Normality of the Post-test
s
2 =
Σ f n
− [
Σ f n
]
=
− [ ]
=
4122.37 −[ . ]
=
4122.37 −
. = 182.3
SD = √
. = 13.50
x̅= 62.77 T
table
= 0.161 T
max
= 0.1264
The result showed that T
max
T
table
0.1264 0.161. It can be concluded that in the significant degree of 0.05, H
o
is accepted. It means that the data is normally distributed.
2. The Homogeneity of the Data
Based on the normality calculation by using Lillyfors formula, the writer got the result that the data of pre-test and post-test in both
experimental class and control class was normally distributed. Then, the writer calculated the homogeneity of the data.
The hypothesis can be seen as follows: H
o
: The sample of experimental class and controlled class is not different. H
a
: The sample of experimental class and controlled class is different.
2 2
2
The criteria of the test: H
o
: F F
αn1-1,n2-1
H
a
: F F
αn1-1,n2-1
- If F F
αn1-1,n2-1
, it means that the sample of experimental class and controlled class in not different. H
o
is accepted and H
a
is rejected. -
If F F
αn1-1,n2-1
, it means that the sample of experimental class and controlled class is different. H
o
is rejected and H
a
is accepted. The formula used can be seen as follows:
F =
�ℎ� ℎ��ℎ� � �� �� �ℎ� �
� � �� ��
or F =
a. Homogeneity of Pre-test Scores
F = .
. F = 1.634
n1-1 = 30 - 1 = 29 n2-1 = 30
– 1 = 29
F
0.05n1-1,n2-1
= 1.854 F
table
Based on the calculation, it can be seen that F F
αn1-1,n2-1
1.643 1.854. It means that the sample of experimental class and controlled class pre-test
is homogeneous. H
o
is accepted and H
a
is rejected.
b. Homogeneity of Post-test Scores
F = .
. F = 1.3735
n1-1 = 30 - 1 = 29 n2-1 = 30
– 1 = 29
F
0.05n1-1,n2-1
= 1.854 F
table
Based on the calculation, it can be seen that F F
αn1-1,n2-1
1.3735 1.854. It means that the sample of experimental class and controlled class post-test
is homogeneous. H
o
is accepted and H
a
is rejected.
C. Hypothesis Testing
The writer analyzed the data by using T-test formula. The aim of this technique is useful to prove whether there is any significant difference between
students’ vocabulary in experiment and controlled class statistically. The experiment class was X variable and the controlled class was Y variable.
The writer needed to make the calculation table, to find out the value of mean, standard deviation and standard error of each variable, before the writer
calculated t-test.
Table 4.3 The Result of Gained Score in Experimental and Controlled Class
Student Score
x y
x² y²
X Y
1 36
14.77 -2.23
218.15 4.97
2 20
4 -1.23
1.77 1.51
3.13 3
10 -11.23
-2.23 126.11
4.97 4
4 3
-17.23 0.77
296.87 0.59
5 26
-6 4.77
-8.23 22.75
67.73 6
24 -3
2.77 -5.23
7.67 27.35
7 10
-11.23 -2.23
126.11 4.97
8 30
-10 8.77
-12.23 76.91
149.57 9
-6 -6
-27.23 -8.23
741.47 67.73
10 40
18.77 -2.23
352.31 4.97
11 16
-10 -5.23
-12.23 27.35
149.57 12
36 6
14.77 3.77
218.15 14.21
13 20
-1.23 -2.23
1.51 4.97
14 33
11.77 -2.23
138.53 4.97
15 14
-21.23 11.77
450.71 138.53
16 17
10 -4.23
7.77 17.89
60.37 17
40 4
18.77 1.77
352.31 3.13
18 34
4 12.77
1.77 163.07
3.13 19
26 7
4.77 4.77
22.75 22.75
20 37
10 15.77
7.77 248.69
60.37 21
16 16
-5.23 13.77
27.35 189.61
22 34
-3 12.77
-5.23 163.07
27.35 23
20 -4
-1.23 -6.23
1.51 38.81
24 17
-7 -4.23
-9.23 17.89
85.19 25
16 10
-5.23 7.77
27.35 60.37
26 23
1.77 -2.23
3.13 4.97
27 -12
6 -33.23
3.77 1104.23
14.21
