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CHAPTER III RESEARCH METHODOLOGY
A. Place and Time of the Research
The research took place in SMP Trimulia Jakarta Selatan. This school is located on Jalan H. Adam Malik, No. 1, Petukangan Selatan
– Pesanggrahan, Jakarta Selatan. The research was conducted on January 20
th
up to February 7
th
2014.
B. Research Method and Design
This research was a kind of quantitative research. There are numbers of research design in quantitative research. Yet, this research used a quasi-
experimental research. Quasi-experiment is a research which involves groups in the research, experiment and control group, but not based on the randomly
formed. The design of the research was illustrated as follows:
Pre-test Treatment
Post-test Experiment Class
√ √
√
Control Class
√ X
√
C. Population and Sample
The population of the study was the students of the eighth grade of SMP Trimulia Jakarta. The eighth grade students are divided into five classes with the
population about 206 students, distributed from VIII.A up to VIII.E. Since the population was considered too large to be used for the
researcher, the purposive sampling technique was used to decide the sample of the research. So the writer took two classes as a sample. First, was the class VIII.B
consists of 41 students as a control class and second was the VIII.B consists of 42 students as an experimental class. But there were some students who did not come
to the pretest and posttest session and absent for 2 times treatment, the researcher decided only took 32 students as the sample from each class. So, there were about
64 students as a sample for this research .
D. Technique of Collecting the Data
The data were collected from test instruments. There were two tests that have been employed, the pre-test and post-test. The pre-test was given at the
beginning of the lesson. It was aimed to ascertain the student’s ability in the
material of the simple past tense that is given to the students. The post-test was given the end of the lesson, to know whether or not there was a change on
students’ understanding of the simple past, following of learning by using the STAD and they were not using the STAD. In collecting a require data, multiple
choice test was used. There were 25 items of multiple choices. Both experiment and control group were given the same test.
E. Internal Validity Control
The instrument of this research was a test. Before the instrument was used to the students as the sample of the research, it has been tested to the eight grade
students of MTs Nur Asy-Sy afi’iyah YASPINA, Rempoa. This step was needed
to see the validity of the instrument before it was applied to the sample of the research. Class VIII.B was chosen and it consisted of 30 students, but there were 3
students who were absent and 2 were sick. So, totally there were about 25 students who did the validity test. The instrument was used for pretest and posttest.
The researcher analyzed the instrument by using the formula of the item analysis in test to see the validity of the instrument. The validity of the test could
be seen from the Index of Difficulty ID and Discriminating Power DP from each answer of the questions. The result showed that there were 10 items of the
test were in level of mediocre, 6 items were excellent, 5 items were good, 3 items were worst and 1 item was poor. In order to make it easier to calculate, the items
which in level of mediocre, worst and poor, were eliminated and also changed. So, totally there were about 25 items of multiple choices that were used as the pretest
and posttest in this research.
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