Try Out Validity of the Test Reliability of the Test

3.6.1 Try Out

Before conducted the research, all the equipment should be prepared well, includes the instrument for it. A good instrument must fulfill two requirements. Two requirements are valid and reliable. Before I gave pre-test, treatment, and post-test, the reading test had to be tried out first to the other class. I chose VIII-G as the class to do the try out and the respondent is 34 students. the activities of try- out had been held on August 15 th 2011. After conducting try out, the data compiled was analyzed to determine the items are valid and reliable or not. The items which were not valid and reliable are not used.

3.6.2 Validity of the Test

According to Gronlund 1998:226, “validity is the extent to which inferences made from assessment result are appropriate, meaningful, and useful in terms of the purpose of the assessment.” Brown 1988:101 added that “test validity is defined as the degree to which a test measures what it claims to be measuring”. It means that researchers must use test that tap the variables of interest clearly as they operationalized. While according to Tuckman, “the validity of a test represents the extent to which a test measures what it supports to measure”. 1978:163 Here, I used the moment product formula to calculate the validity of each item. The formula is: Best, 1981:158 Where: N = number of paired scores = the sum of the X scores item score = the sum of the Y scores the total item score = the sum of the squared X scores = the sum of the squared Y scores = the sum of the products of paired X and Y scores

3.6.3 Reliability of the Test

Reliability is one of the necessary requirements for test. The test could be said properly to be used when they are reliable. According to Brown 2004:20, “reliability is consistent and dependable”. It means that if the tests are given to the same students or matched students on two different occasions, the test should yield similar result. The other opinion from Brown 1988:98, he states that “the reliability of a test is defined as the extent to which the results can be considered consistent or st able”. For the reliability of the test, the formula which is used is: In which: r K – R20 = Kuder Richardson Reliability n = the number of items in the test p i and q i = the proportion of students responding correctly and incorrectly, respectively, to item I s 2 = test variance Tuckman, 1978:163 In addition, in order to get the variance, the formula used is:

3.6.4 Item Difficulty