30
population of participants was randomly divided into two groups of sample: the control group, and the experimental group. The experimental group was taught
using the discussion technique and the control group was taught without using the discussion technique.
In the experimental group, the students were asked to form a group and discussed the particular topics. The chosen topics were interesting and
controversial, so the students are encouraged to develop their critical thinking, cognitive ability, and socio emotional attitude. The activities were focused on
encouraging students to speak. The students were also invited to give opinion, make summary, and interpret the topic. Moreover, each group also presented the
result of the discussion and the rest of a group had a chance to ask questions and give comments or feedbacks.
The researcher compared the pretest results with the posttest results from both groups. Any difference between the two samples is assumed to be the results
of the experiment.
3.2 Research Setting
The study was conducted in SMK N 2 Depok, Yogyakarta. It is located in Mrican, Depok, Sleman, Daerah Istimewa Yogyakarta. It was done in the months
October to December 2012.
3.3 Research Participants
31
This study involved students of the third grade of SMK N 2 Depok. There are 272 students divided into eight classes. Every class has 30-37 students. They
are in the 20122013 academic year.
The researcher chose two classes of the third grade of SMK N 2 Depok based on their characteristics as participants of the research. They had fulfilled the
same requirements to be the students of SMK N 2 Depok in 20122013 academic year. Besides, they were of the same age and school environment. The classes
were XII KA Kimia Analisis and XII TPA Teknik Permesinan A.. Class XII KA has 31 students and XII TPA has 32 students. Therefore, the number of the sample
is 63. Meanwhile, class XII TAV Teknik Audio Video is a sample class of the try-out before the research was applied. Table 2 below presents the distribution of
the treatment.
Table 2. Distribution of the Treatment
No. Class
Group Treatment
Number of the students
1. XII KA Experimental
Classroom discussion method
31 2.
XII TPA
Control Non-classroom
discussion method 32
Total of the students 63
3.4 Instrument and Data Gathering Technique
The research instruments used in this study were pre-test and post- tests. 3.4.1 Pre-test and Post-test
a. Pre-test
32
The pre-test was the speaking test, which was based on what the students had gotten from the school. The speaking items tested were taken from the
School-based Curriculum Kurikulum Tingkat Satuan Pendidikan for the third grade students of vocational schools. The topic was taken from competence
standard and basic competence of the third grade of vocational schools. The topic was determined by the researcher.
b. Post-test The post-test was the second speaking test, which was rewritten based on
the first test. It was done when the treatment had been given. The topic was also taken from competence standard and basic competence of third grade of
vocational schools. The test was given after the treatment. The number of items of the both test, pre-test and post-test are the same.
3.4.2 The Validity and Reliability of the Instrument a. The Validity of the Instrument
A test is valid if it measures what it is supposed to measure. Before the instrument was used, the validity of the instruments was determined .The test
instrument employes content validity. “To measure the effectiveness, content
validity can be applied by comparing the instruments with the material s plan”
Sugyono, 2010:353. Table 2 shows the blue-print of the instrument based on the School-based Curriculum Kurikulum Tingkat Satuan Pendidikan for the third
grade students of vocational schools.
Table 3. Blue Print of the Instrument
No Standard
competence Basic
Competence Indicator
Item Number
33
b. The Reliability of the Instruments Considering the validity of the instruments, the reliability of the
instruments should be found before it is applied. Reliability means that the extent of the test provides consistent results when it is used in similar circumstances. A
reliable test should measure the instrument consistently. A test is reliable if it provides consistent and stable indication of the characteristics being investigated.
To know the reliability of the test, the Test-retest formula is applied. The formula is:
�
=
n X
i
Y
i
− X
i
Y
i
[n X
i 2
− X
i 2
I n Y
i 2
− Y
1 2
]
�
= reliability coefficient
�
= total scores of TAV test 1
�
= total scores of TAV test 2 Sugiyono, 2010: 356
The researcher employed SPSS 16.0 program 2007 edition to analyze the reliability of the test. The computation showed that the reliability coefficient for
try out 1 is 0.0892 see Appendix II, the reliability coefficient for tryout II is 1
3. Communicate in
English on intermediate level
3. 3 Presenting the
report 3. 4
Recognizing the use of user
manual 1. Recognizing the
elements of the report
2. Creating a report 1. Recognizing the
elements of user manual.
2. Creating a user manual
1,2,3,4,5
6,7,8,9,10
34
0.890 see Appendix II, if the instrument test refers to the value of reliability coefficient
α r table, the research instrument can be regarded as reliable.
3.5 Data Analysis Technique
