Based on the table 4.5, it is known that the significant level of independent sample test is .567, which is higher than .05. It means that there was no significant
difference between the post-test score in the experimental class and in the controlled class after the treatment was given. From the t-test, it is found that the
mean of experimental class is 66.20 and controlled class is 63.65. It can be concluded that the mean score of the post-test score in the experimental class is
not different from the controlled class. This could happen because the pre-test score of the experimental class has significantly lower than the controlled class.
Then, in the post-test the experimental class could catch up the controlled class. In other words, there was improvement in the experimental class, which will be
discussed in the result of the t-test anlysis of gained score.
3. t-test Analysis of Gained Score
The gained score was obtained after the writer got the pre-test and post test scores from experimental class and controlled class. Gained score is necessary
because it can show the improvement scores from the experimental class after the treatment. Besides, it also answers the alternative hypothesis H
a
, whether it is accepted or rejected. The t-test calculation by using SPSS is as can be seen in the
table 4.6 in the next page.
Table 4.6 The
t-test of Gained Scores in the Experimental and Controlled Class
The table 4.6 shows that there was a significant difference between the experimental class and controlled class in the gained score M
x
=22.30, M
y
= 3.50, SD
x
= 13.235, SD
y
= 15.985, t38= 4.051, p= 0.000. In addition, the writer also calculate the t-test of gained score manually. The t-test formula with degree
significant 5 will be presented as follow :
Group Statistics
Group N
Mean Std. Deviation
Std. Error Mean
Gain EXP
20 22.30
13.235 2.959
CONT 20
3.50 15.985
3.574
Gain Equal
variances assumed
Equal variances not assumed
Levenes Test for Equality of Variances
F .236
Sig. .630
t-test for Equality of Means
T 4.051
4.051 Df
38 36.722
Sig. 2-tailed .000
.000 Mean Difference
18.800 18.800
Std. Error Difference 4.641
4.641 95 Confidence
Interval of the Difference
Lower 9.406
9.395 Upper
28.194 28.205
Table 4.7 The Comparison of Students’ score in Experimental and Controlled Class.
Students X
Y X
X - MX Y
Y - MX x
2
y
2
1 30
3 7.7
-0.5 59.29
0.25 2
30 24
7.7 20.5
59.29 420.25
3 13
30 -5.3
26.5 28.09
702.25 4
37 -17
14.7 -20.5
216.09 420.25
5 33
13 10.7
9.5 114.49
90.25 6
6 -16.3
-3.5 265.69
12.25 7
10 26
-12.3 22.5
151.29 506.25
8 10
-13 -12.3
-16.5 151.29
272.25 9
30 -10
7.7 -13.5
59.29 182.25
10 34
-7 31.7
-10.5 1,004.89
110.25 11
-3 4
-25.3 0.5
640.09 0.25
12 30
3 7.7
-0.5 59.29
0.25 13
10 -6
-12.3 -9.5
151.29 90.25
14 10
6 -12.3
2.5 151.29
6.25 15
20 7
-2.3 3.5
5.29 12.25
16 26
10 3.7
6.5 13.69
42.25 17
27 10
4.7 -9.5
22.09 90.25
18 53
23 30.7
19.5 942.49
380.25
