25 63.3
33.3 -30
26 66.7
70 3.3
27 76.7
63.3 -13.4
28 66.7
80 13.3
29 70
76.7 6.7
30 66.7
66.7 31
76.7 80
3.3 32
80 63.3
-16.7 ∑
2330.2 2360.3
30.1 Mean
72.82 73.76
0.94
From the table above, it can be shown that in controlled class there are 32 students. The mean of the pre-test in controlled class got 72.82 while in post-test
got 73.76. The lowest score in pre-test is 56.7 and the highest score in pre-test is 83.3. While in post-test, the lowest score is 33.3 and the highest score are 90.
B. Analysis of Data
The writer analyzes the data using T-test formula. This technique is useful to prove statistically whether there is any significant difference between students
’ vocabulary in experiment and control class. The experiment class was X variable
and the control class was Y variable. Before calculate t-test, the writer needs to make the calculation table, to gain
the value of Mean, Standard Deviation and Standard Error from each variable.
Table 4.3 Students’ Achievement
In both Experiment and Control Class
No. X
Y x
y x2
y2 1
70 73.3
-19.9 -0.46
396.01 0.21
2 63.3
86.7 -26.6
12.94 707.56
167.44 3
96.7 56.7
6.8 -17.06
46.24 291.04
4 100
83.3 10.1
9.54 102.01
91.01
5 96.7
80 6.8
6.24 46.24
38.94 6
86.7 86.7
-3.2 12.94
10.24 167.44
7 80
86.7 -9.9
12.94 98.01
167.44 8
96.7 66.7
6.8 -7.06
46.24 49.84
9 100
76.7 10.1
2.94 102.01
8.64 10
96.7 76.7
6.8 2.94
46.24 8.64
11 76.7
73.3 -13.2
-0.46 174.24
0.21 12
60 86.7
-29.9 12.94
894.01 167.44
13 100
56.7 10.1
-17.06 102.01
291.04 14
73.3 66.7
-16.6 -7.06
275.56 49.84
15 100
66.7 10.1
-7.06 102.01
49.84 16
93.3 76.7
3.4 2.94
11.56 8.64
17 96.7
90 6.8
16.24 46.24
263.74 18
100 86.7
10.1 12.94
102.01 167.44
19 66.7
70 -23.2
-3.76 538.24
14.14 20
100 70
10.1 -3.76
102.01 14.14
21 96.7
73.3 6.8
-0.46 46.24
0.21 22
100 80
10.1 6.24
102.01 38.94
23 93.3
76.7 3.4
2.94 11.56
8.64 24
73.3 80
-16.6 6.24
275.56 38.94
25 83.3
33.3 -6.6
-40.46 43.56
1637.01 26
96.7 70
6.8 -3.76
46.24 14.14
27 96.7
63.3 6.8
-10.46 46.24
109.41 28
100 80
10.1 6.24
102.01 38.94
29 90
76.7 0.1
2.94 0.01
8.64 30
96.7 66.7
6.8 -7.06
46.24 49.84
31 96.7
80 6.8
6.24 46.24
38.94 32
100 63.3
10.1 -10.46
102.01 109.41
2876.9 2360.3
4816.61 4110.17
89.90 73.76
The formula of T-test as follows:
In order to get the calculation of T-test, there are several steps to be taken; determining Mean, Standard Deviation and Standard Error from each
variable, the following steps describe as follows:
1. Determining Mean of variable X and Y, the formula in determining Mean
as follow: ∑
∑
2. After getting the Mean in each variable, the next step is determining
Standard of Deviation Score of each variable; X and Y. The formula in determining Standard deviation as follows:
√ ∑
√ √
√ ∑
√ √
3. After getting Standard of Deviation of each variable, the next step is
determining Standard Error Mean of each variable; X and Y, with formula:
√ √
√
√ √
√
4. Determining Standard Error of different Mean of Variable X and Mean of
Variable Y, with formula: √
√ √
√
5. After getting the Mean of each variable and the Standard Error of
different Mean from each variable, Finally, determining t
o
with formula:
After getting the t
hitung
, it is necessary determining Degrees of Freedom df, to know the value of t
tabel
with formula: df
The value of df = 62 is as degree of freedom df. The value of df 62 at the degree of significance 5 0.05 = 1.67
1
see appendix 11 and at the degree of significance 1 0,01 = 2.38.
1
Budi Susetyo. Statistika Untuk Analisis Data Penelitian, Bandung: PT Refika Aditama, 2010, p. 320.
