3.3.1.3.3 Reliability
Reliability of the test shows the stability or consistency of the test scores when the test is used.
According to Heaton 1975:155 he stated that: Reliability is a necessary characteristic of any good test: for it
to be valid at all, a test must first be reliable as a measuring instrument. If the test is administered to the same candidates
on different occasion with no language practice work taking place between these occasions, then, to the extent that it
produces difference results, it is not reliable. 1975:155 In short, in order to be reliable, a test must be consistent in its
measurement. This research will use the formula of Spearman- Brown as cited by Best 1981: 254 the formula as follow:
2 21
1 2
21 1
11
1 2
l l
l
r r
r
11
r = the instrument reliability
2 21
1 l
l
r = the correlation of the scores on the halves of the test
The result of the computation of
11
r can be seen in appendix.
3.3.1.3.4 The Difficulty Level
Difficulty level is a number that shows the easy and difficulties of an item. A good test is a test which is not too easy and difficult. To compute this difficulty
level, this research will use the formula:
Js B
P
Where:
P= the difficulty level B= the number of the students who answered the item correctly
Js= the number of the students in a class The difficulty level of an item as follows:
1 Item with P 0.00- 0.30 is a difficult item, 2 Item with P 0.30- 0.70 is a sufficient item
3 Item with P 0.70- 1.00 is an easy item The result of the computation of difficulty level of the try out test can be
seen in appendix.
3.3.1.3.5 Finding the Mean
The formula used for computing the mean is as follow: m =
n s
Where m
= the mean
s
= the sum of item scores n
= the number of the students Valette 1970:51
3.3.1.3.6 Field Notes
The purpose of using field notes in this study is to know the activities during the teaching learning process, such as what the students’ response while
researcher is presenting the material in the classroom, and what are the difficulties faced by the eleventh grades of senior high school in listening comprehension. By
using field notes, the writer could systematically keep notes the class situation,
either while the lesson is in progress or immediately after the teaching learning process is conducted.
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CHAPTER IV DATA ANALYSIS
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