format to interact with others. Referring to the recent curriculum, the tests I made were valid.
To find out whether the test had content validity, I compared the test with the materials dealing with tense concord, referred to the School-based curriculum
2006:
Standard Competence Basic Competence
4. Speaking Expressing meaning in oral
texts functional and simple short monologue form of
descriptive and recount to interact with the surrounding
environment 4.2 Expressing meaning in simple
short monologue by using a variety of harsh language accurately,
fluently, and thanks to interact with the environment in the form of
descriptive text and recount.
Table 3.4 Standard Competence and Basic Competence According to school-based curriculum KTSP, the eighth-grade students
are demanded to be able to express monologue texts in descriptive and recount type to interact with others. The instruction of the try out test was
“Describe the following picture orally by using your own words in 3-5 minutes with your
partner”. Therefore, based on the school-based curriculum KTSP, the test had the appropriate content validity.
3.6.2 Inter Rater Reliability
Since this study was an oral test, I used the inter rater reliability. It was used because in oral test sometimes human error, subjectivity, and bias may enter into
the scoring process. “The careful specification of an analytical scoring instrument,
however, c an increase rater reliability” Brown, 2004:21. Therefore, in scoring
this oral performance test I used rating table scale which consisting of pronunciation, grammar, fluency, content and vocabulary criteria. The maximum
score was five and the minimum score is one. In scoring of the try out test, I was helped by the two English teachers of
SMP Negeri 3 Petarukan. Therefore, there were three raters in this test. To calculate the result of the try out test, I used the formula:
r = Brown, 2005: 187
Before calculating r-value, the value of standard deviation and the correlation between three raters were found out first. The test is reliable if r-value
r-table. The formulas can be stated as follows:
√
√
√
Brown, 2005: 187
And the formula to calculate the correlation between the three raters is: r
xyz
= Brown, 2005: 187
Where :
To find out whether the try out test was reliable or not, I used inter rater reliability. The test is reliable if r
value
r
table
. In scoring the try out test, I was helped by two English teachers of SMP Negeri 3 Petarukan. Therefore, there were
three raters in this test. The try out scores from three raters could be seen in the Appendix 9. From the results of the try out test from three raters, it is known:
∑X-Mx = 48-36.22 = 11.78 ∑X-Mx
2
= 48
2
– 36.22
2
= 992.11 ∑Y-My = 48- 31.89 = 16.11
∑Y-My
2
= 48
2
- 31.89
2
= 1287.03 ∑Z-Mz
= 52- 36.56 = 15.44 ∑Z-Mz
2
= 52
2
- 36.56
2
= 2667.44 X was the score of the first rater, while Mx was the mean of the first rater‟s
score. Here, the mean of the first rater was 36.22. Y was the score of the second Sx
: standard deviation of rater 1 Sy
: standard deviation of rater 2 Sz
: standard deviation of rater 3 X
: student‟s score of rater 1 Mx
: mean score of rater 1 Y
: student‟s score of rater 2 My
: mean score of rater 2 Z
: student‟s score of rater 3 Mz
: mean score of rater 3 R
xyz :
correlation between 3 raters r
: inter rater reliability n
: number of raters N
: number of students
rater and the mean of the second rater My was 31, 89. Z was the score of the third rater and Mz value was 36.56. The number of the students N was 36 and
the number of raters n was 3. To calculate the result of the try out test I used the formula:
√ =
√ =
5.25
√
= √
=
5.98
√
= √
=
8.61
r
xyz
=
= =
0.30 Therefore, for R
xyz
= 0.30, then I applied the formula as follows,
r = =
= =
0.56 Brown, 2005: 187
The result of inter rater reliability of the try out instruments was 0.56. The test is reliable, if r
value
r
table
. Then, the result was consulted with r
table
for α =
5 with N = 36 was 0.27. r
value
VS r
table
0.56 0.27
3.6.3 Difficulty Level
