Normality Test Click Analyze = Descriptive Statistics = Explore on the menu

H : There was no extreme difference in narrative writing skill between the experimental and the control class before the treatment was given. H 1 : There was extreme difference in narrative writing skill between the experimental and the control class before the treatment was given. b. Calculating t value by using the Independent Sample t-Test on IBM SPSS Statistics 19. The steps are as follow: 17 1 Open file independent sample t test on CD, parametric statistic folder 2 Click Analyze = Compare Means = Independent-Sample T Test on the menu until the dialogue box Independent-Sample T Test appears 3 Fill variable on the box Test Variables and fill another variable on the box Grouping Variable 4 Click Define Groups, fill dependent variable value on the box Group 1 and 2 5 Click Continue until it comes back to the dialogue box Independent- Sample T Test 6 Click Options until the dialogue box Independent-Sample T Test: Option appears. Determining Confidence Interval and Missing Values 7 Click Continue 8 Click OK c. Making decision about t value on the row Equal Variance Assumed it is assumed that the variance is homogenous and using the degree of significant 5 α = 0.05. The criteria of taking decision were: If t count t table or Sig 2-tailed ⁄ , H was accepted. Meanwhile, H was rejected if t count t table or 2-tailed ⁄ α. 17 Ibid, pp. 112-113 After calculating and obtaining the result of the independent sample t test of both the experimental and the control class’ pretest, the last step was to do hypothesis test. Additionally, there were three alternatives that can be done to test the hypothesis: a. If the data pretest and posttest score of the experimental and the control class was normally distributed and had homogenous variance, the independent sample t-test could be done. The steps of doing the independent sample t-test and its criteria were as follow: 1 Formulating the hypothesis: H : There was no positive effect of using picture books in students’ performance in writing narrative text. H 1 : There was positive effect of using picture books in students’ performance in writing narrative text. 2 Calculating t value by using the Independent Sample t-Test on IBM SPSS Statistics 19. The steps of doing the independent sample t-test are similar to the point b. above. 3 Making decision about t value on the row Equal Variance Assumed it is assumed that the variance is homogenous and using the significance degree 5 α = 0.05. The criteria of taking decision were: If t count t table or Sig 2-tailed ⁄ , H was accepted. Meanwhile, H was rejected if t count t table or 2-tailed ⁄ α. 4 Determining the effect size by using Cohen’s d. The effect size is used to identify the strength of the final part of two group differences or the relation between two variables in a quantitative study. 18 18 John W. Creswell, Educational Research-Planning, Conducting, and Evaluating Quantitative and Qualitative Research, New Jearsey: Pearson Educatio, 2008, p. 203