Chapter iii


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Chapter iii

  1. 1. 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. 22
  2. 2. 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. 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. 23
  3. 3. Table 1 Observation Scheme No. Activities Check list Grade 1 2 3 4 5 A. 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 24
  4. 4. 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. 25
  5. 5. Validity shows whether an instrument is valid. In this study, the validity of each item is calculated using the product moment formula7 : ( )( ) ( ){ } ( ){ }2222 yyxx yxxy rXY ΣΝΣΣΝΣ ΣΣ−ΝΣ = −− In which, r XY = coefficient of correlation between x and y variable or validity of each item N = the number of students / subject participating in the test Σ X = the sum of score in each item Σ X 2 = the sum of square score in each item Σ y= the sum of the total score from each student Σ y 2 = the sum of the square score from each student Σ XY = 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: ( )2/21/1 2/21/2 1 1 11 r r r + × = In which, 11r = the reliability of the instrument 2/21/1r = xyr the correlation index of the odd and even The r XY was resulted from this following formula: 7 Suharsimi Arikunto, Dasar-dasar Evaluasi Pendidikan, (Jakarta: PT. Bumi Aksara, 2002), p. 72. 26
  6. 6. r XY = ( )( ) ( ){ } ( ){ }2222 ∑ ∑∑∑ ∑∑ ∑ −Ν−Ν −Ν yyxx yxxy In which, r XY = coefficient of correlation between x and y variable N = the number of students/subject participating in the test Σ X = the sum of odd item Σ X 2 = the sum of the square score of the odd item Σ y = the sum of item Σ 2 y = the sum of the square score of the even items Σ xy = 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: JS B P = In which, P = item difficulty B = number of students who answered the item correctly JS = 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 4.5 Discriminating Power 27
  7. 7. The discriminating power measures how well the test items arranged to identify the differences in the students’ competence. The formula is8 : JB BB JA BA D −= In which, D = number of students in the upper group who answered the item correctly BA = number of students in the lower group who answered in the item correctly JA = number of all students in the upper group JB = number of all students in the lower group The criteria are: D ≤ 0.2 is poor 0. 2 < D ≤ 0. 4 is fair 0. 4 < D ≤ 0. 7 is good 0. 7 < D ≤ 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: lowestVar higestVar F . . max = ( ) ( ) ( )1 22 2 −Ν ΝΧ− = ∑ ∑X SDVarian 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. 28
  8. 8. 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 = assnumberofcl rangeR 4) Make a frequency distribution table 5) Determines the class boundaries (bc) of each class interval 6) Calculating the average Xi ( X ), with the formula: X = ∑ ∑ i ii f xf 7) Calculate variants, with the formula: 1 )( 2 − − = ∑ n xxf S ii 8) Calculate the value of Z, with the formula: Z = s xx − x = limit class x = 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: 29
  9. 9. class bc Z P L Ei Ei EiOi − 12) Calculate the chi-square ( 2 X ), with the formula: ( ) ∑= − = k i i ii E EO X 1 2 2 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 α = 5% 14) Determining the value of 2 X table 15) Determining the distribution normality with test criteria: If countX 2 > tableX 2 so the data is not normal distribution and the other way if the countX 2 < tableX 2 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.       +      −+ + + = NyNxNyNx SScSSe McMe t 11 2 In which, t = t - value Me = the mean of the control group Mc = the meant of the control group SSe = the deviation of the experimental group 9 Sujana, Metode Statistika, (Bandung: Tarsito, 1996), p. 273. 30
  10. 10. SSc = the deviation of the control group Nx = the number of the students in control group Ny = the number of the students in experimental group 31