concern whether the test was actually in line with the language theory or not
Shohamy, 1985:74.
3.5.2.1.2. Reliability
Reliability was aimed to measure how accurate the result of test. In this research, the researcher used the split-half method to estimate the reliability of the test. To
measure the coefficient reliability between the first half and the second half items, the researcher used the Pearson product moment formula as follows:
rk =
XY
2 2
y x
Where: rk
: coefficient of reliability between the first half and the second half items X
: total of items that the students got right in the first half of the test Y
: total of items that the students got right in the second half of test
XY : total score of X times Y
2 x : total score of X
2
2 y : total score of Y
2
Lado: 1961 in Hughes. 1989:32 After having the reliability of the half of the test, the researcher used
“Spearman Brown’s Prophecy formula” Hatch and Farhady, 1982:246 to determine the
coefficient correlation of whole items. The formula is: rk = 2rl
1 + rl
Where: rk
: the reliability of the test rl
: the reliability of half test
The criteria are: 0,90
– 1,00 is high 0,50
– 0,89 is moderate satisfactory 0,0
– 0,49 is low
After conducted the try out test, the result of reliability found through this research was 0.75 see Appendix 5. By referring to the criteria of the reliability
proposed by Hatch and Farhady 1982:268, the test had moderate or satisfactory reliability in the range of 0,50
– 0,89. It indicated that this instrument would produce consistent result when administered in the similar condition to the same
participants and in different time Hatch and Farhady, 1982.
3.5.2.1.3. Level of Difficulty
The test was used to measure the difficulties of the item test. The try out test had given before the treatment and the researcher counted the students correct answer.
If the amount of students who answer correctly was higher than the amount of students who failed, it was assumed that the test is easy for the students. To
determine the level of difficulty, the researcher used the following formula:
N R
LD
Kategori