class is lower than the controlled class. Besides, the mean difference from both classes is 16.250. Furthermore, interval of the difference has between 3.882 and
28.618.
2. t-test Analysis of post-test
After the writer got the result of the t-test score of pre-test both in the experimental class and in the controlled class, the t-test for post-test is also done
in both classes, as in the table 4.5 below:
Table 4.5 The
t-test of the Post-test Scores in the Experimental and Controlled Class
group N
Mean Std. Deviation
Std. Error Mean Score
EXP 20
66.20 11.879
2.656 CONT
20 63.65
15.772 3.527
Score Equal variances
assumed Equal
variances not assumed
Levenes Test for Equality of Variances
F 3.463
Sig. .071
t-test for Equality of Means
T .578
.578 Df
38 35.308
Sig. 2-tailed .567
.567 Mean Difference
2.550 2.550
Std. Error Difference 4.415
4.415 95 Confidence
Interval of the Difference
Lower -6.388
-6.411 Upper
11.488 11.511
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.
