population, the researcher took sample as the representative of the population. According to Best,1977: 268 a sample is a small proportion of a population
selected for observation and analysis. The sample of this research is taken from two classes of eighth grade students of SMP N 6 Semarang in academic year of
20122013. The samples were divided into two groups. The first group as the experimental group EG and the second one as the control group CG. The
sample of this research was the students of VIII B AND VIII C of SMP N 6 Semarang in academic year 20122013. The total sample is 60 students. They
were divided into two groups. The first group was VIII C as the experimental group EG consist of 30 students, and the second one was VIII B as the control
group CG consist of 30 students. see appendix 2
3.3 Research Variable
According to Best 1977: 93 variables are the conditions or characteristics that the experimenter manipulates, control, or observes. The independent variables are
the conditions or characteristics that the experimenter manipulates in her attempt to ascertain their relationship to observed phenomena. The dependent variables
are the conditions or characteristics that appear, disappear, or change as the experimenter introduces, removes, or changes independent variables.
Concerning the research aims, the questions, and the hypotheses addressed in this research, the variables of this study are:
1 Independent Variable. Independent variable is the presumed cause of the dependent variable. In this
experiment, the independent variable is using semantic mapping strategy in teaching reading comprehension of narrative text.
2 Dependent Variable Dependent variable is the presumed effect of the independent variable. The
dependent variable in this experiment is the students’ comprehend in reading narrative text.
3.4 Research Instrument
In any scientific research, instrument for collecting data was absolutely important. The accuracy of the result of research was mostly dependent on how
accurate the use of instrument. Before research carried out, the instrument for the data collection should be well prepared.
Based on the research problems, the writer used reading test as an instrument. Ary 1979: 216 stated that a test is a set of stimuli present to an
individual in order to elicit responses on the basic of which a numerical score can be designed. The score measured by statistic formula. Arikunto 2006: 150 added
“test is a set of questions that is used to measure the skills, knowledge, intelligence, and the talent of an individual or a group.” In this study, the students’
achievement in reading narrative text was measured by using tests, namely pretest
