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CHAPTER III METHOD OF INVESTIGATION
3.1 POPULATION AND SAMPLE
3.1.1 Population
Population is the group of interest to a researcher, to which he or she would like the result of the study to be generalized Gay, 1987:102.
The population selected for the research was the third grade students of junior high school of SLTP Institute Indonesia in the academic year of 20052006.
The total number of the students was 120 students. They were grouped into classes 3A to 3D. The following table describes the classes of the students:
Class Number of students
3A 30 3B 30
3C 30 3D 30
Total 120
The choice of students as the population in this research was based on the following consideration:
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a. The population was homogeneous for the research because they all were in the
same grade and had been studying English for the same period of time. b.
They had been taught question tags in the third grade in the class. c.
By conducting the research to the education class, the writer attempted to render her idea to minimize the students’ mistakes of question tags since they
prepared to be competent teacher.
3.1.2 Sample
Sample is a part or representative of a population that is investigated Arikunto, 1998:118. In this study, the writer did not take whole population as
sample because of time limitation on financial problem. The writer followed the procedure that if the population is less than 100: a researcher can take 50 out of
them as sample Saleh, 2001:34. Therefore, 50 of the population was taken to be respondents. The third grade of SLTP Institute Indonesia in the academic year
20052006 consisted of 4 classes with 120 students. It means that 60 students were taken as a sample of the research.
As stated by Gay, 1987:101 “sampling is a process of selecting a number of individuals for a study in such a way that the individuals represent the larger
group from which they were selected. Consistently the degree to which the selected samples represent the population is the degree to which the results are
generalized. On the average, each class has the same number of students that is 30
students. All of the classes were given the same English materials and treatment
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from teachers so they had the same opportunity to be used as sample. It also means that each of the students as the member of the population had equal chance
of being included in the sample. It has been mentioned before that the writer took 60 students as samples or
50 of the total number of the population. To take those 60 students as sample, the writer used a proportional random sampling because she took the number of
students from each class proportionally. After deciding the number of samples of each class, she started to do the
random sampling. First, she gave numbers to the students 1-30. Second, she wrote the numbers on small pieces of paper. These small pieces of paper were rolled and
put into a box. After being mixed, the pieces were dropped out of the box one by one. The same procedure was done four times until 60 students were obtained.
3.2 INSTRUMENT
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