different values or conditions for different individual.” In this research, there are two variables, they are:
a Independent variable
Tuckmann 1978:58 states that “independent variable is the factor that is measured, manipulated, or selected by the experimenter to determine its
relationship to an observed phenomenon”. Independent variable is a stimulus variable or an input which is introduced to the experimental group. Based on the
definition above, the independent variable of this study was the use of bingo game technique.
b Dependent variable
Dependent variable is measured in a study. This is the response of independent variable. This variable is not manipulated by the researcher, but is affected by the
independent variable. The dependent variable of this study was the students‟
vocabulary mastery.
3.3 Instrument of the Study
An Instrument was very useful in collecting data. Saleh 2001:31 states that “the
word instrument refers to research tools for data collecting. It is therefore, a fundamental thing to be well thought
– out by a researcher before shehe conducts an experiment.” The instrument was used to measure the achievement which is
based from the data which was gotten from students. The instrument was a very important part in conducting a research since it is how the real life was turned into
data on papers. According to Kerlinger 1965:48, “instrument is an important
device for collecting the data in a research study.” Saleh 2001:31 states that “four types of instruments for gathering data: questionnaire, observation,
interview, and test.” This study used tests: pretest, posttest, and questionnaire as the instruments to collect the data. The Guidelines of the test and questionnaire
can be seen in appendix 9 and 10. Tinambunan 1988:27 states “achievement test is designed to indicate
degree of success in some past learning activity. Test is a set of questions, each of which has correct answer, the examinee usually answers orally or in writing.” In
this study I used written test to collect the data. Harris 1974:6 states that “there
are two basic kinds of written test. They are objective test and essay test. ” The
essay test was usually used to measure the four language skills. The focus point of this study was to find out the achievement
in students‟ vocabulary mastery, so the test which was applied in this study was objective test. Tinambunan 1988:55-56
states that: An objective test includes a variety of item types. Objective items can
be classified into supply-type and selection-type. Supply-type which is known as “short-answer” or “completion” requires a pupil to supply the
answer. And the selection-type test is one which requires pupil to select the answer from a given number of alternatives.
The success accuracy of the study could be said it depended on the instruments. The well-thought instrument would guarantee the accuracy
of the data which was gotten from the research. In this study, written test was chosen as an instrument to collect data. Written test would be
both applied to pretest and posttest which were given to both control group and experimental group.
3.4 Methods of Collecting Data
