The eighth grade students of SMP N 2 Sukolilo in the academic year 2010 2011 consist of five classes VIIIA- VIIIE. There are 164 students. If the observed
population is more than 100, then the sample 10- 15 or more than 25. Therefore the writer uses VIII D as first sample. For the second sample, the writer uses class
VIII students of MTS Miftahul Fallah Wotan in academic year 2010 2011. Because the population of this school less than 100, so the writer took the whole population
sample.
3.3 Variable
According to Best 1981: 59 variable is the condition or characteristics that an investigator or a researcher manipulates, control or observes. In this research there
were two variables; first dependent variable according to Hartoyo dependents variable is a response variable or output. It is an observed aspect of the behavior of an
organism that has been stimulated. The dependent variable is that factor which is observed and measured to determine that effect of the independent variable. Based on
the definition, the dependent variable of this study is students’ achievement in reading comprehension.
Independent variables which is a stimulus variable or input, operates either within a person or within hi or her environment to affect behavior. It is that factor
which is measured, manipulated or selected by experimenter to determine its
relationship to an observed phenomenon. Based on the definition, the independent variable of this study was visual aids.
3.4 Research Design
The writer used visual aids as a media to measure reading comprehension. Therefore, she would see
what will happen to students’ achievement in reading comprehension in both schools SMP N and MTS when they are taught by using visual aids. She
chose one group pretest-posttest design with one treatment as the design for this study. She conducted this same treatment in both schools. The following was the
design of the research she would conduct: Table 1. Research Design
G Test
Independent Variable
X Test
Dependent Variable
Y E
Pre-test X
1
Post- test
Y
1
Where; E
: Experimental Group SMP N Students and MTS Students. These groups will be taught through visual aids.
X : Independent Variable
X
1 :
Independent Variable for the groups using visual aids.
Y : Dependent Variable
Y
1 :
Dependent variable for the results or students learning achievement of group through visual aids.
The effectiveness of the instructional treatment is measured by comparing the average score of the pre-test and the post test. When it turns out that the post-test
average score is significantly higher than the average score of the pre-test, then it is concluded that the instructional treatment is effective. After knowing the results of
each group, she compares the results of each group and decides the best one.
3.5 Instruments for Collecting Data
