Place and Time of The Research Method of The Research

vocabulary mastery before conducting the treatment. Here is the rubric to measure students’ vocabulary. Rubric for Vocabulary Words Indicator 3 2 1 Words Identified Identified more than 8 words. Identified 4 or 5 words. Identified less than 4 words. Synonyms Each word had a correct synonym for vocabulary word Has identified a synonym that does completely work for word. Synonym doesn’t match the meaning or the word. Antonyms Each word had a correct antonym for vocabulary word Has identified an antonym that does completely work for word. Antonym doesn’t match the meaning or the word. Definitions Definitions were detailed and accurately matched the meaning. Definitions accurately matched the meaning and context clues in sentence. Most definitions accurately matched the meaning and context clues in sentence. Sentence Sentence accurately used the vocabulary word in a structurally sound sentence. Sentence accurately used the vocabulary word, but the sentences had structural errors. Sentence did not use the word accurately, but sentence was structurally sound. Then, after the pre-test, the writer conducted the treatment to experimental class. The treatment was given for four meeting on 17 th , 18 th , 21 st , and 23 rd of November 2016. After that, the writer gave the post-test to both class on 24 th and 25 th of November 2016. It was used to find out the result after the treatment and the effectiveness of suggestopedia method on students’ vocabulary mastery.

E. Research Instrument

The writer uses pre-test and post-test as the research instruments to collect the data. It was consist of 25 numbers of vocabulary test which consists of 15 numbers of multiple choice questions and 10 word matching task in every pre-test and post- test. The test was used in order to know the different achievement between the experimental class and controlled class after the treatment. Before the test was given to the students, the writer has already measured the validity and reliability of the test. Validity is “the process of collecting and analyzing evidence to support such inferences.” 5 Validation in language testing is needed to ensure the defensibility and fairness of interpretations based on test performance. According to Frankael , “reliability refer to the consistency of the scores obtained —how consistent they are for each individual from one administration of an instrument to another and from one set of items to another .” 6 In this research, the writer measures the validity and reliability of the research instrument by using ANATES V.4. F. Data Analysis Technique In this study, the writer used T-test to find out the differences between students’ score which are taken from pre-test and post-test in experimental class and controlled class. Before calculated the T-test, the writer measured normality and homogeneity test, first. Moreover, the writer used SPSS v.18 for Windows software to analyze normality test and homogeneity test.

1. Testing Requirement

a Normality Test Normality test was done on two classes; those are experimental class and 5 Frankael, Loc.Cit, p. 148 6 Ibid., p. 154