CHAPTER 11I

METHOD OF INVESTIGATION

1. Data Collection

1.1 Test

Test is a number of questions that used to measure personality,

intelligence, attitude and achievement someone. In this research, the

researcher will give pre-test and post-test. Pre-test will be given at the

beginning of research to both control and experiment class (similar

question that related to the topic) while post-test will be given to

experiment class because it is the point that researcher can compare the

differences result of the test between control and experiment class.

2.1 Population

Population is all of the research subject1. In this research, the researcher

will take population of eight grade students of SMP NU 05 Awwalul

Hidayah Gemuh kab. Kendal in the academic year of 2009/2010 which has

two classes (VIII A and VIII B) and each class consist of 43 students.

3.1 Sample

Sample is a part of population to be researched2 . Sample is a subset of

individuals from a given population3. Sample must be reflective with the

true example in the field. In this case, the researcher will take sample from

eight grade students of SMP NU 05 Awwalul Hidayah Gemuh kab.

Kendal in the academic year of 2009/2010 which has two classes (VIII A

as an experiment class and B as a control class).

1 Suharsimi Arikunto. Prosedur Penelitian: suatu pendekatan praktek. (Jakarta: Rineka Cipta, 2006), p. 130.

2 Ibid, p. 131.3 David Nunan. Research Methods in Language Learning. (New York: Cambridge

University Press, 1992), p. 27.

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4.1 Variable

To answer the research problems, there are some variables that the

researcher wants to investigate. The variables are as follow:

a. Independent Variable (X)

Independent variables are the conditions or characteristics that are

manipulated by the researcher in order to explain the relation with

the observed phenomena4. The independent variable of this study,

according to the definition above is the using of mind-mapping to

improve students’ understanding on modal.

b. Dependent Variable (Y)

Dependent variables are the conditions or characteristics that

appear, disappear, or change as the researcher introduces, removes,

or changes independent variables5. Referring to the definition, the

dependent variable of the study is the improvement of students’

understanding on modal.

5.1 Observation

Observation is an activity to observe something by using sense toward a

particular object. In this research, the researcher will observe of school,

students and English teacher of the school. In this research the writer will

use check list (√) to get the data. The observation is used to know the

activities during teaching and learning process, such as how teacher is

explains the material, what is the students’ respond and how is the

student’s work in doing the test.

Table 1

4 Narbuko and Achmadi, Metodologi Penelitian, (Jakarta: Bumi Aksara, 2004), p. 119.5 J. W. Best, Research in Education, (New Jersey: Prentice Hell, 1981), p. 60.

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Observation Scheme

No. Activities Check list Grade

1 2 3 4 5A. Teacher preparation of lesson

Specification of aims

Choice of appropriate material

Choice of appropriate teaching aids

B. Teacher organization of the lesson and

the class

Introduction or explanation of

material

Manage the classroom

Motivate students

C. Students’ activities

Students’ participation toward

teacher’s explanation

Students are active during learning

and teaching process

Students’ work communication

during in a group work

Students’ seriousness in

understanding the material

Students are active in answering the

teacher’s question

In which, percentage

1 : poor 0 %-35 %2 : fair 40 %-59%3 : average 60 %-74 %4 : good 75 %-84 %5 : excellent 85 %-100 %

2. Focus of The Research

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This research is experimental study. An experiment is defined as a situation in

which one observes the relationship between two variables by deliberately

producing a change in one and looking to see whether this alteration produces

a change in the other6. In research, the writer will use experiment to teach

class (VIII A) by using mind-mapping to improve students’ understanding on

modal and control class (VIII B) without using mind-mapping.

3. Participant and Setting

The participants that used by the researcher are the students on eight grade at

SMP NU 05 Awwalul Hidayah Gemuh Kendal. There were 118 students, VIII

A (59 students) and VIII B (59 students).

4. Instrument of The Study

The writer used one test type only. It was multiple choice completions. This

type of test was chosen because of the following advantages:

a. The technique of scoring is easy.

b. It was easy to compute and determine the reliability of the test.

c. It was more practical for the students to answer.

4.1 Try Out

The quality of the data, whether it is good or bad, is based on the

instrument used. A good instrument fulfills two important qualifications,

such as reliability and validity. So, before the test was used an instrument

to collect the data, it had been tried out first to the students in another

class. After the result of the try out was gained, the analysis was made to

find out the validity and reliability of the items of the test. Some items

remained to be used while some others were left out.

4.2 Validity of the Test

6 James Dean Brown and Thedore S. Rodgers, Doing Second Language Research, (New York: Oxford University Press, 2002), p. 211.

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Validity shows whether an instrument is valid. In this study, the validity of

each item is calculated using the product moment formula7:

In which,

r = coefficient of correlation between x and y variable or validity

of each item

N = the number of students / subject participating in the test

= the sum of score in each item

= the sum of square score in each

item

y= the sum of the total score from each student

y = the sum of the square score from each student

= the sum of multiple score from each students with the total

score in each item

4.3 Reliability of the Test

Reliability shows whether an instrument is reliable and can be used as a

device to collect the data with the stability of t-set score. The formula

which is used is the split half spearman-brown. In this case, the writer split

the formula is as follows:

In which,

= the reliability of the instrument

= the correlation index of the odd and even

7 Suharsimi Arikunto, Dasar-dasar Evaluasi Pendidikan, (Jakarta: PT. Bumi Aksara, 2002), p. 72.

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The r was resulted from this following formula:

r =

In which,

r = coefficient of correlation between x and y variable

N = the number of students/subject participating in the test

= the sum of odd item

= the sum of the square score of the odd item

= the sum of item

= the sum of the square score of the even items

= the sum of multiple of score from odd and even

4.4 Degree of Test Difficulty

After try out was conducted, each item is classified in the difficulty level

by using this formula:

In which,

= item difficulty

= number of students who answered the item correctly

= number of students

The level of difficulty of each item was determined by using this following

categorization:

0 < P 0.3 is difficult

0. 3 < P 0. 70 is medium

0. 7 < P 1 is easy

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4.5 Discriminating Power

The discriminating power measures how well the test items arranged to

identify the differences in the students’ competence. The formula is8:

In which,

= number of students in the upper group who answered the item

correctly

= number of students in the lower group who answered in the item

correctly

= number of all students in the upper group

= number of all students in the lower group

The criteria are:

0.2 is poor

0. 2 < 0. 4 is fair

0. 4 < 0. 7 is good

0. 7 < 1 is very good

4.6 Homogeneity Test

Homogeneity test is used to compare variants in a group of three

categories data or more and its categories can be compared fairly if

each category is homogeneity.

The formula as follows:

4.7 Normality Test

It is used to know the normality of the data that is going to be analyzed

whether both groups have normal distribution or not. To find out the

8 Ibid, p. 213.

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distribution data is done normality test with the Chi-square. Step by

step Chi-square test is as follows:

1) Determine the range (R); the largest data reduced the

smallest.

2) Determine the many class interval (K) with formula:

K = 1+ (3,3) log n

3) Determine the length of the class, using the formula:

P =

4) Make a frequency distribution table

5) Determines the class boundaries (bc) of each class

interval

6) Calculating the average Xi ( ), with the formula:

=

7) Calculate variants, with the formula:

1

)( 2

n

xxfS ii

8) Calculate the value of Z, with the formula:

Z =

x = limit class

= Average

S = Standard deviation

9) Define the wide area of each interval

10) Calculate the frequency expository (Ei), with formula:

Ei = n x wide area with the n number of sample

11) Make a list of the frequency of observation (Oi), with the

frequency expository as follows:

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class bc Z P L Ei

12) Calculate the chi-square ( ), with the formula:

13) Determine the degree of validity (dk). In the calculation

of this data is arranged in list of frequency distribution consisting of

k pieces so that the interval to determine the criteria test used

formula dk = k-3, where k is the number of class intervals and =

5%

14) Determining the value of table

15) Determining the distribution normality with test criteria:

If > so the data is not normal distribution and the

other way if the < so the data is normal distribution. 9

5. Method of Data Analysis

To see whether the differences of the students’ understanding in “modal”

between those who was taught using mind-mapping and these who was taught

without using mind-mapping is significant or not, the t- test formula is used.

In which,

= - value

= the mean of the control group

= the meant of the control group

= the deviation of the experimental group

= the deviation of the control group

9 Sujana, Metode Statistika, (Bandung: Tarsito, 1996), p. 273.

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= the number of the students in control group

= the number of the students in experimental group

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