47
4.2.2 Reliability
In a test, the reliability of the test is needed to be calculated for the category of a good test. The reliability of the test was calculated from the number of items, the means of
scores, and the total of variants. A test is considered to be reliable if r
11
result of calculation is higher than r in the table 0.338788. From the calculation for
α significance level 5 and the number of students was 34, the result was 0.34. Since
the r
11
is higher than r
table
, the test was considered to be reliable. While in the try out of post-test, the result was 0.37. Therefore, it was also considered to be reliable.
4.2.3 Level of Difficulty
Level of difficulty is calculated from the number of students who answered correctly and the total number of the students. After calculating the item number 10 for
example, the index of difficulty level is 0.64. According to the criteria, the difficulty level of item number 10 was medium.
There were three categories for level of difficulty. They were difficult, medium, and easy. After calculating 40 items of try-out test, there were 32 items that
were easy, 7 items were medium, and 1 item was difficult. While in the result of try out for post-test, there were 44 items that were easy, and 6 items were medium.
4.2.4 Discriminating Power
Discriminating power is calculated from the number of students in the upper and lower group who answered correctly and the number of all students in the upper and
48
lower group. After calculating the item number 10, the discriminating power of it was 0.25. Therefore the criterion of the item number 10 was satisfactory.
In discriminating power, there were four categories. They were poor, satisfactory, good, and excellent. From 40 items of try-out test, there were 20 items
that were poor, 18 items were satisfactory, and 2 items were good. Whereas, in the result of try out for post-test, there were 33 items that were poor, 15 items were
satisfactory, and 2 items were good.
4.3 The Difference between Pre-Test and Post-Test Result in every Aspect of Reading Comprehension Skills
The result of pre-test and post-test in this research was analyzed in each aspect of reading comprehension.
4.3.1 Result of Pre-Test
In the result of the pre-test, I would like to describe the average score of pre-test in every aspect of reading comprehension in the form of percentage. The aspects are
scanning, vocabulary knowledge, topics, topics of paragraph, pattern of organization, skimming, and making inferences.
I tried to calculate the percentage of the average score based on the result of those aspects in pre-test see appendix. From result, it showed that the mean of the
score was 74.86. Besides, the aspect of scanning showed that averagely 88.05 from all scanning items in the pre-test were correctly answered by the students. Besides, in
the aspect of vocabulary knowledge, there were vocabulary and grammar aspects that
49
were measured. It showed that averagely 66.27 of all vocabulary items and 60.18 of all grammar items in pre test were correctly answered by the students. In the pre-
test, there was one topic test item. The number showed in table was 52.78. It means that not all the students answered this item correctly. In finding the topic of paragraph,
there were 3 test items in the pre-test. The result showed that averagely 77.78 of the items were correctly answered by the students. The next aspect is main idea in which
averagely 50 of all main idea items were correctly answered by the students. Since there was one main idea item in the pre-test, it means that not all students can answer
the item correctly. The following aspect is the aspect of patterns of organization. From all of the patterns of organization items in pre-test, averagely 64.81 were
correctly answered by the students. In the next aspect, which is skimming aspect, the students were averagely answered 78.70 of all skimming items correctly. The last
aspect is making inferences aspect. The result showed that the students averagely answered 77.78 of all making inferences items in the pre-test correctly.
4.3.2 Result of Post-Test
Kategori