The Score DATA DESCRIPTION

Table 4.4 The Result of Normality Test of the Experimental and the Control Class’ Pretest Score Tests of Normality Class Kolmogorov-Smirnov a Statistic Df Sig. Pretest Score Experimental .166 26 .063 Control .168 26 .056 a. Lilliefors Significance Correction Table 4.5 The Result of Normality Test of the Experimental and the Control Class’ Posttest Score Tests of Normality Class Kolmogorov-Smirnov a Statistic Df Sig. Posttest Score Experimental .139 26 .200 Control .165 26 .068 a. Lilliefors Significance Correction . This is a lower bound of the true significance. The test of normality above was done to check whether a group of the data came from population which was distributed normally or had normal curve shape. The result of the normality test above showed that significance level or probability value p of the experiment al class’ pretest score was 0.063 and the control one was 0.056. Similarly, the probability value p of the experimental class’ posttest score was 0.200 and the control one was 0.068. Based on the criteria of normality hypothesis testing which was determined, the criteria of normality hypothesis testing were mentioned that if the significance levelprobability value ≥ the degree of significance α = 0.05, the sample data was normally distributed. In the contrary, the sample data did not come from population having normal distribution if the significance levelprobability value the degree of significance α = 0.05. The result of normality test proved that the probability value p was higher than the degree of significance α = 0.05. In this case, it could be concluded that the sample data of both the experimental and control class’ pre and posttest score was normally distributed. For the complete statistical calculation, it can be seen in the APPENDIX 6. In addition, the normal histograms of the experimental and control class’ pretest and posttest score also proved that the data met the requirement of normal distribution because the histogram was symmetrical and had a shape like a bell-curve indicating that the distribution of the data was normal. The normal histograms of the experimental and the control class’ pre and posttest was presented in the APPENDIX 7.

b. Homegeneity Test

Similarly, after finishing the normality test, the homogeneity test was also required as a prerequisite analysis test to test the similarity of the sample which is taken from homogenous population. To calculate homogeneity test, the researcher used Levene Statistic Test from IBM Statistics SPSS 19 software. The following is the result which was obtained from this calculation: Table 4.6 The Result of Homogeneity Test of both the Experimental and Control class’ Pretest Test of Homogeneity of Variances Pretest Score Levene Statistic df1 df2 Sig. 1.847 1 50 .180 From the result of the Levene Statistic Test above, it could be seen that the significance level or probability value p of the data from the experimental and the contr ol’s pretest score was 0.180. This result meant that the significacance level or probability value p of the data was higher than the degree of significance α = 0.05. Based on the criteria of homogeneity hypothesis testing the researcher determined, the criteria of homogeneity hypothesis testing were mentioned that if the significance levelprobability value ≥ the degree of significance α = 0.05, the sample data came from population which had homogenous variance. Conversely, the sample data came from population which did not have homogenous variance if the significance levelprobability value the degree of significance α = 0.05. Therefore, it could be interpreted that the sample data came from population which had homogenous variance. The complete statistical calculation was presented in the APPENDIX 8.

c. Test Analysis

After finishing the statistical analysis of prerequisite test including the normality and homogeneity test, the researcher continued to do analytical testinghypothesis testing. Due to both the experimental and the control class’ pre and posttest which met the requirement of normality and homogeneity test, the researcher was able to use independent sample t-test to test the hypothesis. However, the independent sample t test was not only used to see the significant difference in both the experimental and the control class’ posttest after the treatment was given, but it was also done to see if there was no extreme difference in both the experimental and the control class’ pretest before the treatment was given. The independent sample t test was also performed in both the experimental and the control class’ pretest to show that both of the classes had similar ability in narrative writing skill before the several writing instruction was given to the control class and the treatment was given to the experimental one. The following is the result obtained from the