Instruments and Data Gathering Technique

25 Table 3.1 The Data Analysis Table No Problem Data Required Instrument 1. How guessing meaning from context procedure is implemented in vocabulary learning in class 8A of SMP Negeri 15 Yogyakarta The students‟ works and the result of observation 1. Student worksheet 2. Observation sheet 2. What are the results of the implementation of guessing meaning from context procedure in vocabulary learning in class 8A of SMP Negeri 15 Yogyakarta The students‟ pretest and posttest results, the students‟ responses toward the questionnaire 1. Pretest and posttest 2. Questionnaire In order to find the answer to whether or not the guessing meaning procedure could help the students in class 8A of SMP Negeri 15 Yogyakarta, the researcher had to compare the mean of the pretest result of the research subjects to the mean of the posttest using dependent t-test. For determining whether or not there had been a significant, positive difference between the mean of the pretest and posttest score, the researcher used dependent t-test. Figure 3.1 shows the formula for the dependent t-test. Figure 3.1 The Dependent t-Test Formula 26 Where: t : t ratio D : average difference ∑D 2 : different scores squared, then summed ∑D 2 : different scores summed then squared N : number of pairs The result of the t-test, known as t , would then determine the researcher‟s decision to either retain or reject the null hypothesis. Ary, Jacobs, and Razavieh et al. 1990 explain “the null hypothesis is a statement that there is no actual relationship between the variables and that any observed relationship is only a function of chance” p.162. A null hypothesis must always be tested in a negative sentence and can either be retained or rejected by a researcher depending on the result of a statistical test done previously. In order for a researcher to retain or reject the null hypothesis, the t-test must either exceed or be less than t-values required for significance at a certain level. By retaining the null hypothesis, a researcher states that he did not find any or less than enough evidence to prove that his experimentation had led to a change he had expected, or that any change observed after the experimentation could not be attributed to the variables he had modified. By doing the opposite, researcher state that the change observed after the experimentation was likely to be the result of their experimentation; that the variables that had been modified caused the PLAGIAT MERUPAKAN TINDAKAN TIDAK TERPUJI 27 change. This statistical research theory would be used by the researcher to answer question number one. The researcher formed an assumption of the null hypothesis in this research as mentioned below:  Null Hypothesis H o There is no significant difference between the mean of the pretest scores and the mean of the posttest scores.  Alternative Hypothesis H 1 The mean of the posttest scores is significantly higher than the mean of the posttest scores. The theory of level of significance is an important part of the null hypothesis. Ary et al. 1990 define the level of significance as the “predetermined level at which a null hypothesis would be rejected” p.165. The researcher must determine the level of significance before she carries out her research. The level of significance one chooses may vary, but the most used level of significance is the .05 level, as was the level of significance set by the researcher before experiment. If a researcher decides that she uses the .05 level significance for her research and based on the test of significance she rejects the null hypothesis, she implies that she does not believe that “the null hypothesis is true because the chance is only 5 out of 100 .05” Gay, 1992, p.431. Apart from the theory of level of significance, another inseparable part of any type of tests of significance is degrees of freedom. According to Gay 1992, degrees of freedom constitute “a function of such factors and the number of PLAGIAT MERUPAKAN TINDAKAN TIDAK TERPUJI 28 subjects and the number of gro ups” p. 434. Different formulas to determine degrees of freedom apply depending on the test of significance a researcher would like to carry out. This research for instance, used the t-test for dependent samples. The formula used to determine the degrees of freedom is df = N-1, with N being the number of research subjects. There are 33 students in the 8A class but only 30 students who are involved in this study, so the degrees of freedom of the study are 29.

F. Research Procedure

In order to conduct the research, the researcher did several steps in this research. The following is the explanation of how the research was conducted.

1. Asking permission to conduct a research

Before conducting the research, the researcher asked permission to the SMP Negeri 15 Yogyakarta. In the first step, the researcher asked an oral permission with the vice principal of SMP Negeri 15 Yogyakarta. And the next step was the researcher gave the letter of research permission see Appendix 1. It was given on Monday, 22 nd February 2016.

2. Setting the research place and range of time

In this procedure, the English teacher of SMP Negeri 15 Yogyakarta was kindly to give permit to the researcher. The place for conducting the research was class 8A. The class was conducted every Wednesday at 11:45-13:05 and Thursday at 07:15-08:35.