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adapted and taken from the module used in the English course, in which students of PMat 2010 were taking at that time. Besides, to support high face validity, the
researcher also consulted the test items to the advisor and revised them two times.
b. Reliability
“Reliability of a test is the extent to which a measuring device is consistent in measuring whatever it measures” Ary, Jacobs, Razavich, 1990, p. 256. In
addition, Brown 2004 states that reliability can be achieved by making sure that all test takers receive the same quality of input. Besides, it should represent the
degree of consistency about what was being measured. Mostly, the reliability focuses on the score achieved by the test takers compared to equality of the test
items given. According to Ary, Jacobs, and Razavich, the reliability of a test is divided
into four types of method. They are the test-retest reliability, the equivalent-forms reliability, the split-half reliability, and the homogeneity measures reliability
1990. In order to support appropriate answer to the second research question, the researcher preferred to use the fourth method which is the homogeneity measures
reliability. Homogeneity measures reliability refers to the method of estimating
reliability of a test which recognizes that the whole test items are equal Ary, Jacobs, Razavich, 1990. There is no need to establish the different difficulty
level of each item the grouped into two groups like what is found in the split-half technique. By using homogeneity measures reliability, the researcher did not need
to establish the different difficulty level of each test item and then grouped into
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two halves. The researcher recognized that the whole test items included in the test sheet were equal.
Furthermore, to give the best answer, particularly to the second research question, the researcher had to make sure that the test, which was used as the
research instrument, was reliable. Thus, the researcher used a formula proposed by Kuder-Richardson to compute the reliability of the test used in the research.
The formula, which is determined based on the proportion of correct and incorrect responses, is known as Kuder-Richardson formula 20 Ary, Jacobs, Razavich,
1990, p. 277. The formula can be seen as follows: K S
x 2
– Σ
pq
r
xx
= K
– 1 S
x 2
where: K = number of items on the test
S
x 2
= variance of scores on the total test squared standard deviation p = proportion of correct responses on a single item
q = proportion of incorrect responses on the same item The computation of the test reliability gave result as shown in the reliability scale
which is: 0.86 see Appendix D.
The scale of reliability as shown above determined that the test given to the samples of research, which were students of PMat 2010, was reliable.
According to Purpura 2004, the test reliability ranges on a scale from zero 0 to one 1 in which the zero scale represents low reliability and one scale represents
high or perfect reliability. In addition, Gall, Gall, and Borg propose a theory that a test which yields scores with reliability scale higher than 0.80 is considered
having sufficient reliability especially for research purposes 2007.
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E. Data Gathering Technique
