score the students argumentative writing by using assessment rubric. The raters were the English teachers of SMA Kharisma Bangsa and the researcher herself.
E. Technique of Data Collection
Before collecting the data the researcher rechecked to make sure that the students were ready to do the test. The first test that was being administered was
critical thinking test and continued by argumentative writing test. 1.
The Steps of Critical Thinking Test a.
Firstly, the participants were asked to fill out the name, date of birth, grade and students’ number in the answer sheet.
b. The participants were asked to read the direction of the test
c. The researcher explained the direction of the test and how to answer the
test. After the participants were ready, the test was started and the researcher supervised the test took place.
d. The participants had to finish 71 questions of critical thinking test in 50
minutes. e.
After the participants completed the test, the participants’ answers were scored and the results were analyzed.
2. The Steps of Argumentative Writing Test
a. The writing test was conducted in the same day directly after the
participants finished the critical thinking test. b.
Firstly, the participants were asked to fill out the name, date of birth, grade and students’ number in the answer sheet.
c. The participants were asked to read the direction and the scoring criteria
of the test. d.
The participants were free to choose one from the 3 topics given. e.
The students were asked to write argumentative essay in 30 minutes with the length of the essay was at least 250 words.
f. After the participants finished the writing test, their writings were scored
and the results were analyzed by using assessment rubric.
� a + bX
F. Technique of Data Analysis
After the data of students’ critical thinking skill and argumentative writing
skill had been collected, the scores of the two tests were analyzed to determine whether there was correlation or not between two variables covered in this study.
At the end, this analysis could be useful to examine the truth or false of this study hypotheses. In this study, the parameter statistic was used to calculate the data.
Therefore, as the requirement in the parameter statistic in correlation research, the linearity and normality distribution of the data had to be examined first.
1. Test of Linearity
Linearity test aimed to determine whether the two variables significantly had a linear relationship or not. This test was used as a prerequisite in the analysis
of correlation. The formula is as follow:
Regression line a = a regression
b = b regression Moreover, to find out the regression line, the variance analysis table
ANOVA was used in this study.
2. Test of Normality
Testing normality was employed to check whether the population had normal distribution or not. The formula of normality test is as follow
4
:
=Ʃp-ɸ
= value of Ʃp = sum value of data probability
ɸ = value of Kolmogorov table
To get the ɸ value, the standard score of the data z had to be calculated first
with formula:
4
Budi Susetyo, Statistika untuk analysis data penelitian, Bandung: Refika Aditama, 2010, p. 148
—150.
