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CHAPTER III METHODS OF INVESTIGATION
This chapter presents the method of investigation which comprises the explanation about research design, population and sample, research variables, type
of data, instrument for collecting data, method of collecting data and method of analyzing data.
3.1 Research Design
The method of research design was held through a quantitative research. Best 1981: 154 states that “quantification has been defined as a numerical method of
describing observation of material or characteristic.” The research is true experimental. According to Christensen 2001: 32,
“an experimental research is a research that attempts to identify cause and effects relationships. The design used in this study is the pre test-post test control group
design . It involves two groups, an experimental group and a control group. Both
groups are pre-tested, and post-tested. The prominent difference between those groups is administered the treatment. The experimental group has treatments using
CIRC method while the control group has treatments using conventional method. The pre test-post test control group design is clearly depicted in Figure 1.
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Figure 3.1 Best, 1981: 73
E : experimental group
C : control group
O
1
: pre test for experimental group O
2
: post test for experimental group O
3
: pre test for control group O
4
: post test for control group X
: treatment using CIRC Y
: treatment without using CIRC
3.2 Object of the study
Only by providing the object, a research can be administered. In this research, I decided the population and the sample to be the object of the research.
3.2.1 Population
In this study, the population is the eleventh grade students of SMA N 1 Banjarnegara in the academic year 20102011.
E O
1
X O
2
C O
3
Y O
4
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3.2.2 Sample
After obtaining the population, then I choose the sample. Sample is a small proportion of population selected for observation and analysis. Saleh 2001:33
states that “sample is a group of people, goods, or things in which the data is taken. Sample is actually the part considered to represent the population.”
In taking the sample, I also took the number of the population as the consideration. Saleh 2001: 34 suggests that when the number of population is
between 100 and 500, the number of population should be about 30-50. For example, if the number of population is about 200 students, thus, the minimum
number of sample of the study is 60 students. In this research, the number of the population is 224 students which fulfill the requirement that the sample must be
30-50 of the population. Thus, the sample of this research is 63 students. I used cluster random sampling to choose the sample because the population has
heterogeneity and consists of clusters. In this research, the sample is two classes, one for the control group and the other is for the experimental group. The
experimental group is XI IPA 1 of SMA N 1 Banjarnegara while XI IPA 2 as the control group. I also used one class to hold the try out test which is called by the
try out class that is XI IPA 4. This class has the similar ability with the experimental and control group.
3.3 Research Variable
Variable is simply described as something that can vary about its condition. Nunan 1993: 25 states that a variable is anything which doesn’t remain constant.
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Meanwhile, according to Christensen 2001: 144, by variable I mean any characteristics of an organism, environment, or experimental situation that can
vary from one organism to another, from one environment to another or from one experimental situation to another. In this research there are two variables named
independent variable and dependent variable. These are the variables of this research:
1. Independent variable of this research is the use of CIRC method in reading class.
2. Dependent variable is represented by the students’ reading comprehension and writing achievement.
3.4 Instrument for Collecting Data
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