JS = the maximum score of each item
Below are the criteria in defining difficulty level of the test item:
Interval of Difficulty Level
Criteria
0.00 P
0.30 Difficult
0.30 P
0.70 Medium
0.70 P
1.00 Easy
According to the computation of difficulty level Appendix 10, 164, the aspect item
number 1 was considered medium. The Appendix 12 shows that the results of the
difficulty level of the whole aspects are medium.
4.2.2.4 Discriminating Power
The following formula was used to find the discriminating power:
The computation of the discriminating power was presented in Appendix 11, 165. In
defining discriminating power, the test is considered significant if t value t table. Thus,
based on the computation, the five‐aspects in writing was considered significant
Appendix 11, 165.
4.2.2 Pre‐Test
The students were given pre‐test in order to measure their ability before the treatment
was given. In this case the pre‐test is aimed to find out the students’ prior ability in
t =
⎪⎭ ⎪
⎬ ⎫
⎪⎩ ⎪
⎨ ⎧
− +
−
∑ ∑
1
2 2
2 1
i i
n n
X X
ML MH
writing report. The experimental group, XI IPS 1 class, was given pre‐test on Friday,
September 3
rd
2010. On the contrary, XI IPS 2 class, as the control group, was given pre‐
test on Saturday 4
th
2010. XI IPS 1 class actually consisted of 30 numbers of students and XI
IPS 2 consisted of 32 numbers of students. However, the pre‐test data gathered from the
experimental and control groups were only 27 and 28 numbers of students. Meanwhile,
the post‐test data gathered were 26 for the experimental group and 27 numbers
for the control one. Avoiding the problem caused by the difference numbers of student
who involved the pre‐test and post‐test of those groups, the writer then took only
25 numbers of valid students who did both pre‐test and post‐test in gathering the data
analyzed for each group. Thus, during pre‐test there were only 25 data gathered. The
result of the pre‐test is presented in Appendix 13 for the experimental group and Appendix
15 for the control one. After
analyzing the pre‐test result, it was found that the average score of the experimental
group was 58.40, while the control group was 59.04. It meant that the students’
achievement of the two groups was relatively the same since there was no slight
difference of the pre‐test score between the experimental and control groups. Or, in
other words, the students of both experimental and control groups had similar ability in
writing report before the treatment was conducted. The computation of the t‐test in Appendix
17 also proved that there is no significant difference between data pre‐test of the
two groups. The chart of the students’ average score of those two groups, covering the
five‐elements in writing scoring system, is presented below.
Chart 4.1
The Average Score of Pre‐Test of Experimental and Control Group
4.2.3 Post‐Test
