students in experimental class by using suggestopedia method and in controlled class without using suggestopedia method. After four meetings, the writer gave the post-
test to the both classes. It was given to know the effectiveness of Suggestopedia method on students’ vocabulary understanding.
C. Population and Sample
Creswell said that population is a group of individuals who have the selection
of individuals from a sample.
2
It means that population is
the set of entities under study.
In this research, the population is the whole students of the eighth grade at 166 Junior High School which consist of 245 students, that are divided into seven classes
namely class VIII 1, VIII 2, VIII 3, VIII 4, VIII 5, VIII 6 and VIII 7. For the research, the writer determined the sample by using purposive
sampling. Purposive sampling should be representative the whole population, based on the teach
er’s judgment and the sample should have same background.
3
The writer chose this sampling because of the basis of the teacher
’s judgment and the sample has been chosen for specific purposes, in this case, the purpose was the students with
average level of English vocabulary knowledge.
4
Therefore, the writer takes two classes namely class VIII 6 30 students as the controlled class and class VIII 7 30
students as the experimental class.
D. Data Collection Technique
In this research, the writer used Test as the data collection. Test was used to know the achievement of students’ vocabulary mastery before and after the treatment.
First, the writer gave pre-test to both class which was VIII 6 and VIII 7 on 14
th
and 16
th
of November 2016. The pre- test was to measure students’ achievement in
2
Ibid., p. 141
3
Frankael, Jack R, How to Design and Evaluate Research in Education, New York: The Mac Grow-Hill Companies, 2012, p.100
4
Louis Cohen, Lawrence Manion and Keith Morrison, Research Method in Education, Sixth edition, New York: Madison Avenue, 2007, p. 114
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.
