17 From the graphics 4.2, it shows that the pre-test score in control class is still
varied after the treatment. Thus the treatment has affected the whole class not only several students. The students who get lower score in pre-test improved their score
from previously 34 to 56.
In this research, there were 32 participants in experiment class with the mean score of pre-test is 40.375, while the pre-test is 62.5625. Moreover, the
gained score in experiment class was 22.1875. The wide range of the gained score increase in experimental class before and after giving the treatment can
be concluded as significant. Meanwh
ile,
there were 32 participants in control class where the mean score of pre-test reach 37.875, while the post-test
score was 56.125. the score gained from pre-test to post-test not as significant as experimental class, only 18.25 points.
As previously mentioned in chapter III, in analyzing the data, the writer uses statistic calculation of the t-test formula with the degree of significance
5.
Table 4.2 Standard Deviation Table Students
X1 Gained
Score X2
Gained Score
X
1
X
2
X
1 2
X
2 2
1. 16
6 -6.2
-12.2 38.44
148.84 2.
26 8
3.8 -10.2
14.44 104.04
3. 20
-2.2 -18.2
4.84 331.24
4. 28
18 5.8
-0.2 33.64
0.04 5.
22 4
-0.2 -14.2
0.04 201.64
6. 20
14 -2.2
-4.2 4.84
17.64 7.
30 32
7.8 13.8
60.84 190.44
8. 36
6 13.8
-12.2 190.44
148.84 9.
10 38
-12.2 19.8
148.84 392.04
10. 26
16 3.8
-2.2 14.44
4.84 11.
32 4
9.8 -14.2
96.04 201.64
12. 30
22 7.8
3.8 60.84
14.44
18
13. 8
60 -14.2
41.8 201.64
1747.24 14.
14 14
-8.2 -4.2
67.24 17.64
15. 10
16 -12.2
-2.2 148.84
4.84 16.
36 24
13.8 5.8
190.44 33.64
17. 22
-0.2 -18.2
0.04 331.24
18. 2
4 -20.2
-14.2 408.04
201.64 19.
30 30
7.8 11.8
60.84 139.24
20. 12
2 -10.2
-16.2 104.04
262.44 21.
20 40
-2.2 21.8
4.84 475.24
22. 36
28 13.8
9.8 190.44
96.04 23.
24 32
1.8 13.8
3.24 190.44
24. 16
22 -6.2
3.8 38.44
14.44 25.
40 4
17.8 -14.2
316.84 201.64
26. 14
34 -8.2
15.8 67.24
249.64 27.
10 36
-12.2 17.8
148.84 316.84
28. 20
40 -2.2
21.8 4.84
475.24 29.
20 30
-2.2 11.8
4.84 139.24
30. 36
4 13.8
-14.2 190.44
201.64 31.
32 -4
9.8 -22.2
96.04 492.84
32. 12
-10.2 -18.2
104.04 331.24
N=32 ∑X1 =
710 ∑X2 = 584 ∑X1 = -
0.4 ∑X2 =
1.6 ∑ X12 =
3018.88 ∑ X22 =
7678.08
The writer used t-test formula to find out the effectiveness of the teaching writing by using peer feedback as follows:
M1 = =
= 22.1875 M2 =
= = 18.25
19
t
o
=
t
o
=
t
o
=
t
o
=
t
o
=
t
o
= t
o
= 2.857
Determining t-table in signific ance level 5 with dƒ:
dƒ = N1 + N2 -2 = 32 + 32
– 2 = 62
The value of t
table
is │1.67│. From the statistic calculation result, it can be seen that the value of t
o
is 2.857 and the degree of freedom in the table of significance dƒ is 62.
B. Data Analysis
As mentioned in chapter one, this research is conducted in order to know whether teaching writing using peer feedback at SMA N 11 Kota Tangerang
Selatan is more effective than using teacher feedback.
20
To answer the questions above, the writer made a null hypothesis and alternative hypothesis. According to Anas Sudjiono, if t
o
t
t
, the null hypothesis H
o
is rejected, on the contrary the alternative hypothesis H
a
is accepted. It means that between variable x and y is significance. Meanwhile, if t
o
t
t
, the null hypothesis is accepted and the alternative hypothesis is rejected. It means
that there is no significance increase between variable x and y. By comparing the value of t
o
= 2,857 and t
table
on the degree of significance 5 = 1.67, the writer concludes that t
o
is higher than t
table
, 2,857 1,67 which means that the alternative hypothesis is accepted and the null
hypothesis is rejected. In conclusion, teaching writing by using peer feedback is more
effective to increase students’ writing achievement than teaching writing by using teacher feedback.
C. Discussion
As explained in the first chapter, the purpose of this study is to find out whether peer feedback
can improve students’ writing achievement. In this section, the writer tries to discuss the findings of the research from the result of
pre and posttest of experiment and control group. Before analyzing the hypothesis, the researcher calculated normality to
find the data has normal distribution. Whenever the data has normal distribution, it can be calculated by using statistical parametric where the data
is assumed as valid as it counted by refering to several parameters. After calculating the normality test, the writer counts the mean in each experiment
and control group. The result shows that mean of experiment group was higher than control group.
Table 4.3 Normality Test Result of Experiment Class
Normality Test Result of Experiment Class Tests of Normality
Kolmogorov-Smirnov
a
Shapiro-Wilk Statistic
df Sig.
Statistic df
Sig. .123
32 .200
.973 32
.590 . This is a lower bound of the true significance.
a. Lilliefors Significance Correction
21
Table 4.4 Normality Test Result of Control Class
Normality Test Result of Control Class Tests of Normality
Kolmogorov-Smirnov
a
Shapiro-Wilk Statistic
df Sig.
Statistic df
Sig. preex
.079 32
.200 .968
32 .438
. This is a lower bound of the true significance. a. Lilliefors Significance Correction
The table 4.3 shows the result of normality test in experiment and control class. The result of normality test reach 0.590 or higher than the table of 0.05.
Meanwhile, the table 4.4 shows the result of normality test in control class which reach 0.438 or higher than the table of 0.05. It can be concluded that the
data used in experiment and control class are normal and assessed as valid to be used in this research.
After variance of experiment and control group was found, the writer calculates homogenenity test to determined t-test formula. Based on the
calculation of homogenity test, it could be seen that the test is homogeneous in both classes. The result of the homogenous test could be seen in the table
below.
Table 4.5 Homogenity Test Result of Experiment Class
Test of Homogeneity of Variances
preex Levene Statistic
df1 df2
Sig. 1.804
7 14
.165
Table 4.6 Homogenity Test Result of Control Class
Test of Homogeneity of Variances
preex Levene Statistic
df1 df2
Sig. 2.316
8 14
.081
