Place and Time Research Method and Design

Before conducting test to the sample, the writer should try out the items of test to another group of students. It was intended to check the eligibility of test items. The category of good items is interpreted from the value of validity, reliability, index difficulty power, and discriminating power that has been calculated by AnatesV4 software with the basic formula as follows: 2 a. Validity N : Number of students X : Score of test items Y : Total score After conducting try out, it was found that there was one invalid item, five items is adequate, ten items is significant, and the rest is very significant. The result of item analysis is described as follows df = 0,304: Table 3.2 Item Validity of Multiple Choice and Essay Category Multiple Choice Essay Very Significant 14 1 Significant 10 5 Adequate 5 4 Insignificant 1 - Source: ANATES V4 Based on the table above, the insignificant item 23 could not be used because the correlational value is really low. For the adequate items, they need to be checked in depth to know whether the stem or the optional was bad. Then, the errors should be changed before they are going to be used as pre-test and post-test item. 2 Zainal Arifin, Evaluasi Pembelajaran, Bandung: PT REMAJA ROSDAKARYA, 2011, pp. 254—280. b. Reliability k : number of items ΣSa² : number of variance of test items S² : variance of total score X : score for each item Table 3.3 Category of Reliability Value Remark 0.00 – 0.20 Unreliable 0.21 – 0.40 Less reliable 0.41 – 0.60 Sufficient 0.61 – 0.80 Reliable 0.81 – 1.00 Very Reliable Try out was conducted to 37 students who were not the sample of this research. This try out was proposed to know the quality of test. After conducting try out, it showed the value of test reliability of multiple choice test was 0.85 and essay was 0.77. It means that this test was very reliable and good to be used. c. Difficulty Level Difficulty level is used to know whether the items are easy or difficult for students. Good test item is the item that can be answered by the upper group and the lower group cannot. The higher value of difficulty level gotten, the easier test item will be. The formula of calculating difficulty level is: DL : difficulty level