31
the study, population and sample, research instruments, data collection and data analysis.
A. Time and Place of Study
For this study, the time of this study was done about 2 months since 04 November 2015 – 04 January 2016. This study was applied for VII students of SMP Nusantara Palangkaraya.
B. Research Type
This study used an experimental research. An experimental research is scientific investigation in which the researcher manipulates one or more independent variables, controls any other relevant variables, and observes the effect of the manipulations on the independent variable. So, in thisstudythe
researcher tookonegrouporclasstousepretestand
posttestdesigntoknowtheresultoftreatment.
C. Research Design
In this study, the study used pre-experimental method by using one- group Pre-Test/ Post-Test Design. It is one of the most frequently used designs in education.34 It can be diagrammed as follows:
34 Wido H. Toendan, Educational Research Methods: An Introduction, Palangka Raya:
English Language Education Study Program, Language Education Department Teacher Training and Education Faculty University of Palangka Raya, 2006, p.27
Explanation:
X1 : Pre-Test X2 : Post Test Y : Treatment
In this experiment, the researcher taught the student directly. Firstly, the researcher gave pretest to students in order to measure the students’
mastery in mastery vocabulary especially about noun before using pc game media. Secondly, the researcher taught the students for four times by using pc game media. Nouns were discussed in each meeting in different topic. Third, there was posttest in order to measure the students’ mastery after treatment.
The process of teaching learning was started from 4th November 2015 till 4th January 2016. In order words, there were four times for doing treatment. Meanwhile, pretest was done in the first meeting or before treatment and posttest was done in the last meeting or after the treatment.
Therefore, the total meeting was six times.
D. Population and Sample
The population of this study is the seventh grade of SMP Nusantara Palangka Raya which it has one class. In this grade, the amounts of students were 12. The researcher chose this class with 12 students as a sample to observe by using purposive sampling
X1 Y X2
Table 3.1 The Number of The Seventh Grade Students of SMP Nusantara Palangka Raya
Classes The Number of Students
VII 12
All Students 12
E. Research Instrument
Instrument is one of the most important parts of the research.
Instrument of this study was test, the purpose was to measure the students’
mastery of the vocabulary. In this case, the researcher used test.
Test
The researcher gave the test instrument. First pre-test was held on Wednesday, November 11th 2015 period 13.15-14-15 which followed by 15 students. Last the researcher gave post-test on Wednesday, December 30th 2015 period 13.15-14-15 which followed 15 students. The time allocation of each test process was 60 minutes.
Related of the study, test was used to get data for measuring students’
ability in vocabulary mastery. The major data in the study were the data of the students’ English score those were taken from pre-test and post-test. The kind of this test is objective test was constructed in the matching words from which consist of 79 items. In this test, the type of vocabulary used is a noun.
F. Research Instrument Try Out
In order to prove the test were suitable to the students who were the sample of this study, the researcher conducted a try out test. Then the researcher choose students in the another school. The tryout test had been conducted to the seventh grade of MTS Fathul Jannah Palangka Raya on
March 30, 2015. The kind of this test is objective test was constructed in the matching words from which consist of 100 items. In this test, the type of vocabulary used is a noun.
If the result is valid, it means that the test items as the instrument of this suitable to be given. There are the procedures that in carrying out this try out as follows: preparing the instrument; telling the students how they must do with the test of tryout; giving the test items to the students; collecting to the student’s work; calculating the result of the test; analyzing the result of the test; if the result is valid, it means that the test items as the instrumentation of this study are suitable to be given
From the information by English teacher at MTS Fathul Jannah Palangka Raya about how well the individual student had mastered, the final scores were related to the following qualification:
Table 3.2
The Standard Evaluation
Score Criteria
70 – 100 0 – 69
Mastery Fail
From the result of try out, it will find the instrument of validity, reliability, and index of difficulty.
G. Research Instrument Reliability
Reliability is a necessary characteristic of any good test for it to be valid at all. A test must first be reliable as a measuring instrument. The researcher used the formula of KR-20 (Kuder Richardson) to measure the reliability of the test instrument
𝑟11 = 𝑘
𝑘 − 1 𝑆𝑡2 − ∑piqi 𝑆𝑡2 Where:
K : Number of test items
pi : the number of subject answer per item qi : 1 - pi
St2 : total variant35
Then the classifications of the reliability are:
0.800 – 1.000 = Very high reliability 0.600 – 0.799 = high reliability 0.400 – 0.599 = fair reliability 0.200 – 0.399 = poor reliability 0.000 – 0.199 = very poor reliability36
35Sugiyono, Statistika Untuk Penelitian, bandung: ALFABETA, 2004, p. 278.
36Suharsimi Arikunto,Dasar-Dasar Evaluasi Pendidikan, Jakarta: Bumi Aksara, 1999.
The result of reliability has been calculated by using Kuder Richardson (KR20) formula where some of the data have known like St2
= 378.06222,
∑Y= 824, ∑Y2 = 50936, K = 100, ∑piqi = 22.48.
The formula to find out the total variance as follow:
𝑆𝑡2 =∑𝑌2 (∑𝑌)𝑁 2 𝑁
𝑆𝑡2 =50936(824)15 2 15
𝑆𝑡2 =50936 − 45265.067 15
𝑆𝑡2 =5670.933 15 𝑆𝑡2 = 378.0622
The formula to find out the coefficient of reliability as follow:
𝑟11 = 𝑘
𝑘 − 1 𝑆𝑡2− ∑𝑝𝑖𝑞𝑖 𝑆𝑡2 𝑟11 = 100
100 − 1 378.06222 − 22.48 378.06222 𝑟11 = 100
99 355.58222 378.06222 𝑟11 = 1.0101 0.94053
𝑟11 = 0.9500393Very High Reliability
Table 3.3 The Result of Instrument Reliability
Coefficient KR-20 Criteria Number of Items 0.950 Very High Reliability 100
Based on the result of instrument reliability above, it was known that the coefficient of reliability was 0.950 with the criteria very high reliability. It meant that the instrument could be used as the instrumentation of the study.
H. Research Instrument Validity
After the try out had been done, the researcher measured the validity, the reliability and the difficulty level of test items.
1. Validity
Validity is a measurement which shows the grades of number of an instrument. A valid instrument must have high validity, it means that an instrument which lacks validity is said to be invalid instrument.
An instrument is called a valid one when it can measure something which is wanted by uncovering the variable studied exactly. The method used in measuring the validation of the instrument is called content validity. A test or a measurement can be called a content test when it measures the special purpose which is equal with the material or content given.
a. Content validity
The kind of validity depends on a careful analysis of the language being tested and of the particular course objective. The test should be so constructed as to contain a representative sample of the course, the relationship between the test items and the course objectives
always being apparent.37 It is to measure how well the instrument gives for the students.
b. Construct validity
It is capable of measuring certain specific characteristic in accordance with a theory of language behavior and learning. This type of validity assumes the existence of certain learning theories orconstructs underlying the acquisition of abilities and skill.38 It is conducted by field test.
In order to find the validity of test item, product moment correlation was used as the formula to calculate from the tryout test result. The formula is as follows39:
rxy = N ∑XY − (∑X)(∑Y)
N. ∑X2− (∑𝑋)2 𝑁. ∑𝑌2− (∑𝑌)2
Where:
rxy : Total coefficient of correlation ΣX : Total Value of Score X
ΣY : Total Value of Score Y
ΣXY : Multiplication Result between Score X and Y N : Number of students
37 J.B. Heaton, Writing English language Test, Longman, 1974, p. 154.
38Ibid
39 Ridwan, Metode dan Teknik Menyusun tesis, Bandung: Penerbit Alfabeta, 2008, p. 110
To know the level of validity of instrument, the value of was interpreted based on the qualification of validity as follows:
Then the classifications of the reliability are:
0.800 – 1.000 = Very high validity 0.600 – 0.799 = high validity 0.400 – 0.599 = fair validity 0.200 – 0.399 = poor validity 0.000 – 0.199 = very poor validity40
Here are two examples to calculate the validity, for the result data can be seen at the table of the result of instrument try out test
a) Item No. 1
N ∑XY − (∑X)(∑Y)
N. ∑X2 − (∑𝑋)2 𝑁. ∑𝑌2 − (∑𝑌)2
rxy = 15 335 − (5)(824)
15.5 − 25 15.50936 − 678976 rxy = 5025 − 4120
75 − 25 764040 − 678976 rxy = 905
50 85064 rxy = 905
4253200
rxy =2062.3287807719905 = 0.438824308Valid
40 Ibid
rxy>tt = Valid rxy<tt = Invalid
b) Item No. 4
rxy = N ∑XY − (∑X)(∑Y)
N. ∑X2− (∑𝑋)2 𝑁. ∑𝑌2− (∑𝑌)2
rxy = 15 389 − (7)(824)
15.7 − 49 15.50936 − 678976
rxy = 5835 − 5768
105 − 49 764040 − 678976 rxy = 67
56 85064 rxy = 67
4763584 = 67
2182.563630 = 0.0307 𝐈𝐧𝐯𝐚𝐥𝐢𝐝
The validity percentage of each criteria Valid = Total Valid Item
Total Item X 100%
= 79
100 X 100%
= 79%
Valid = Total Invalid Item
Total Item X 100%
= 21
100 X 100%
= 21%
Based on the result of instrument validity above, it could be found that there were seventy nine items which were valid and there were twenty one items which were invalid
Table 3.4 The Valid Items
Test Items Score
1 0.439
2 0.421
3 0.493
5 0.386
6 0.541
7 0.526
9 0.512
10 0.389
12 0.450
14 0.438
15 0.386
16 0.653
17 0.653
18 0.543
21 0.628
23 0.491
25 0.601
28 0.457
29 0.456
31 0.647
34 0.588
35 0.683
37 0.529
38 0.471
39 0.318
40 0.437
42 0.390
43 0.585
44 0.435
45 0.437
Test Items Score
46 0.477
48 0.429
49 0.634
50 0.494
51 0.493
53 0.402
54 0.564
55 0.473
56 0.395
57 0.557
58 0.458
59 0.491
60 0.410
61 0.424
63 0.401
65 0.395
66 0.452
67 0.428
68 0.501
69 0.440
70 0.466
71 0.410
72 0.408
73 0.464
74 0.570
75 0.541
76 0.392
78 0.370
79 0.457
80 0.452
81 0.444
82 0.464
83 0.421
84 0.512
85 0.494
86 0.370
87 0.402
Test Items Score
88 0.419
89 0.439
90 0.466
91 0.490
92 0.445
93 0.413
94 0.388
95 0.431
96 0.581
97 0.536
98 0.519
99 0.416
100 0.424
In this case, the items could be used as the instrumentation of study.
Table 3.5 The Invalid Items
Test Items Score
4 0.030
8 0.096
11 0.003
13 0.290
19 0.265
20 0.321
22 0.004
24 0.303
26 0.182
27 0.093
30 0.303
32 0.326
33 0.199
36 0.161
39 0.318
41 0.279
47 0.180
52 0.344
62 0.344
64 0.200
77 0.175
I. Index of Difficulty
To know the quality of instrument neither too difficult nor easy, the formulation uses:
𝑃 =𝐵 𝐽 Where:
P = Index of difficulty
B = the number of students who answer the question correctly J = the number of all students who follow the test
Then classifications of the difficulty are:
0.00 < 0.30 = difficult 0.30 – 0.70 = fair
> 0.70 = easy
Here are the examples to calculate index of difficulty, for the detail data can be seen on the table of the index of difficulty
a) The test item no 1 𝑃 =𝐵
𝐽 𝑃 = 5
15
𝑃 = 0,33Fair
b) The test item no 17 𝑃 =𝐵
𝐽
𝑃 =154 = 0,27Difficult
c) The test item no 15 𝑃 =𝐵
𝐽 𝑃 =11
15
𝑃 = 0,73Easy
Table 3.6 Index of Difficulty (Fair) No. of test
item
Index of Difficulty
Classification Right
Answer
Number of
Student Total
1 5 15 0.33333333 Fair
4 7 15 0.46666667 Fair
5 7 15 0.46666667 Fair
6 5 15 0.33333333 Fair
7 8 15 0.53333333 Fair
8 10 15 0.66666667 Fair
9 8 15 0.53333333 Fair
10 9 15 0.6 Fair
11 7 15 0.46666667 Fair
12 8 15 0.53333333 Fair
13 6 15 0.4 Fair
14 9 15 0.6 Fair
18 9 15 0.6 Fair
19 8 15 0.53333333 Fair
21 7 15 0.46666667 Fair
22 10 15 0.66666667 Fair
23 5 15 0.33333333 Fair
26 7 15 0.46666667 Fair
27 7 15 0.46666667 Fair
28 5 15 0.33333333 Fair
29 8 15 0.53333333 Fair
30 10 15 0.66666667 Fair
31 8 15 0.53333333 Fair
No. of test item
Index of Difficulty
Classification Right
Answer
Number of
Student Total
32 9 15 0.6 Fair
33 7 15 0.46666667 Fair
34 8 15 0.53333333 Fair
35 6 15 0.4 Fair
36 9 15 0.6 Fair
40 9 15 0.6 Fair
41 8 15 0.53333333 Fair
43 7 15 0.46666667 Fair
44 10 15 0.66666667 Fair
45 7 15 0.46666667 Fair
46 10 15 0.66666667 Fair
47 8 15 0.53333333 Fair
48 7 15 0.46666667 Fair
49 9 15 0.6 Fair
50 8 15 0.53333333 Fair
51 10 15 0.66666667 Fair
52 10 15 0.66666667 Fair
53 6 15 0.4 Fair
54 9 15 0.6 Fair
56 8 15 0.53333333 Fair
57 9 15 0.6 Fair
58 7 15 0.46666667 Fair
59 9 15 0.6 Fair
60 7 15 0.46666667 Fair
61 6 15 0.4 Fair
62 8 15 0.53333333 Fair
63 8 15 0.53333333 Fair
64 10 15 0.66666667 Fair
65 9 15 0.6 Fair
67 8 15 0.53333333 Fair
68 7 15 0.46666667 Fair
70 7 15 0.46666667 Fair
72 9 15 0.6 Fair
74 5 15 0.33333333 Fair
75 7 15 0.46666667 Fair
76 9 15 0.6 Fair
No. of test item
Index of Difficulty
Classification Right
Answer
Number of
Student Total
77 9 15 0.6 Fair
78 8 15 0.53333333 Fair
79 9 15 0.6 Fair
80 6 15 0.4 Fair
81 7 15 0.46666667 Fair
82 9 15 0.6 Fair
84 5 15 0.33333333 Fair
86 9 15 0.6 Fair
87 8 15 0.53333333 Fair
88 9 15 0.6 Fair
89 10 15 0.66666667 Fair
90 9 15 0.6 Fair
92 9 15 0.6 Fair
93 9 15 0.6 Fair
94 5 15 0.33333333 Fair
95 7 15 0.46666667 Fair
96 6 15 0.4 Fair
97 5 15 0.33333333 Fair
99 8 15 0.53333333 Fair
Table 3.7 Index of Difficulty (Easy) No. of
item
Index of Difficulty
Classification Right
Answer
Number of
Student Total
2 11 15 0.73333333 Easy
3 13 15 0.86666667 Easy
15 11 15 0.73333333 Easy
16 11 15 0.73333333 Easy
20 13 15 0.86666667 Easy
24 11 15 0.73333333 Easy
25 13 15 0.86666667 Easy
37 11 15 0.73333333 Easy
38 11 15 0.73333333 Easy
42 13 15 0.86666667 Easy
69 13 15 0.86666667 Easy
71 11 15 0.73333333 Easy
73 13 15 0.86666667 Easy
83 11 15 0.73333333 Easy
85 11 15 0.73333333 Easy
91 11 15 0.73333333 Easy
98 13 15 0.86666667 Easy
100 11 15 0.73333333 Easy
Table 3.8 Index of Difficulty (Diffficult) No. of
item
Index of Difficulty
Classification Right
Answer
Number of
Student Total
17 4 15 0.26666667 Difficult
39 4 15 0.26666667 Difficult
55 3 15 0.2 Difficult
66 2 15 0.13333333 Difficult
Based on the result of calculation above, there was four items that was difficult, there was seventy eight items that was fair and there were eighteen items that was easy.
J. Data Collection Procedure
Collecting data is very important in the research. In this study, the researcher uses documentation, observation, and test to collect the data.
In this study the researcher used some procedure to collect the data. The procedures consist of some steps as follow:
1. The researcher observed the school at 21 September 2015 on seventh grade of SMP Nusantara Palangka Raya to know the number of class, the number of students and the class activity
2. The researcher gave tryout to another class before testing for pre-test and posttest at 23 September 2015 on seventh grade of MTS Fathul Jannah Palangkaraya.
3. The researcher gave pretest at 11 November 2015 on seventh grade of SMP Nusantara Palangka Raya
4. The researcher taught the students using Pc game “Big City Adventure”
about noun consist of common noun.
5. The researcher gave post-test at 30 December 2015 on seventh grade of SMP Nusantara Palangka Raya
6. The researcher gave score to the data
7. The researcher analyzed the obtained data from mean of post test score 8. The researcher interpreted the statistical result
9. The researcher concluded the activity of the study whether the use of Pc game “Big City Adventure” about noun to teach vocabulary gives effect or not to the students’ vocabulary mastery score.
K. Data Analysis Procedure
In order to analyze the data which had been collected, the researcher did some procedures below:
a. Collecting the students’ vocabulary score of pretest and posttest.
b. Arranging the obtained score into the distribution of frequency of score table
c. Calculating mean, median modus, standard deviation and standard error students’ score.
d. Calculating the ttest to answer the problem of the study, whether pc game media gives effect toward the seventh year students’ English vocabulary score by using the following formula:
𝑡 = 𝑀
𝐷𝑆𝐸
𝑀𝐷Where:
MD = Mean of difference between pretest and posttest score SEMD = Standard error of mean of difference
e. Calculating the degree of freedom by using the following formula
f. Determining the level of significant of tobserved by comparing the tobserved with the ttable
g. Testing hypothesis
h. Interpretating the result of analyzing i. Giving conclusion
df = N - 1
