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3.5.1.1 Validity
The test can be said valid if the result of the test can describe the fact of the research Setiyadi, 2006:14. If the test is considered to be valid so the test will be
reliable. In this research, the researcher used content validity and construct validity to measure whether the test had good validity or not. The researcher
considered that face validity was less needed since validity only concerned with the layout of the test.
3.5.1.1.1 Content Validity
Content validity is the extent to which a test measures a representative sample of the subject matter content Hatch and Farhady, 1982:251. To get content validity
of the test, the researcher adopted the material based on the objective of teaching in syllabus KTSP 2006 for the ninth grade of junior high school students and
represents the materials in the class. In line with the syllabus for the ninth grade of junior high school at the first semester, the students were required to be able to
comprehend the meaning of short functional text in narrative and report form.
3.5.1.1.2 Construct Validity
Construct validity is concerned whether the test is actually in line with the theory of what it means to know the language. To know whether the test is true reflection
of the theory of language that is being measured, it means that the items should really test the students whether they have mastered the reading text. According to
Heaton 1991:161 states that construct validity is capable of measuring certain
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specific characteristics in accordance with a theory of language behavior and learning and it assumes the existence of certain learning theories underlying the
acquisition of abilities and skills.
3.5.1.2 Reliability
Reliability refers the consistency of the test, and how the test can measure the same subject in different time but it has the same results Setiyadi, 2006:16. In
other words, the test procedures consistent in its score and give us an indication of how accurate the test score are. To measure the coefficient of reliability between
odd x and even y, the researcher used Pearson Product Moment Formula to measure the correlation coefficient of reliability between odd and even number
reliability of half test Heaton, 1975: 164, in the following formula:
=
�Σ − Σ Σ �ΣX²−ΣX² NΣY²−ΣY²
Notes : Rxy : Correlation of coefficient of reliability between odd and even numbers
N : The number of students who take part in the test
X : The total number of odd number items
Y : The total number of even number items
X² : the square of X
Y² : the square of Y
ΣX : the total score of odd number ΣY : the total score of even number
Hatch and Farhady, 1982:198
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