Critical Thinking Skill Data

Descriptive Statistic Rater 1 Rater 2 Skewness .126 282 Standard Error of Skewness .398 .398 Kurtosis -.454 -.232 Standard Error of Kurtosis .778 .778 Sum 2667.0 2660.0 Based on Table 4.2 represented above, it shows the central tendency of argumentative writing skill data between two raters. It indicates that the score appears the most mode score is 82.0; while, the mode score given by the second rater is 73.0. Next, it is found that the middle scores median based on two raters are same which the point is 76.0. In addition, the average score mean given by the first rater is higher than the score given by second rater which the mean is 76.20 76.0. Similarly, the maximum and the minimum score given by rater 1 are higher than the second rater given. It shows that the maximum score is 89.0 88.0 and the minimum score is 64.0 62.0. Meanwhile, the variability distribution of argumentative writing data based on rater 1 and rater 2 is shown in various score. The difference is found in the standard deviation that is 5.9597 and 6.0973. The range score of argumentative writing data based on the rater 1 is 25.0; while, the range score that is given by second rater is 26.0. The variance coefficients based on the two raters are 35.518 and 37.176. The scores that are rated by both raters show the difference but not really significant see the appendix 4. Then, the scores from which each rater is given are compared and summed. The histogram below is the final score of argumentative writing skill: Figure 4.2 Final Score of Argumentative Writing Skill Test The final score of argumentative writing test is represented in Figure 4.2 above. It reveals that the most score appears is 75.0, and it is also as the middle score median score. The minimum score gained is 63.5 and the maximum score is 88.5. Meanwhile, the average score mean of the final score of argumentative writing is 76.0. Additionally, the histogram above describes that the argumentative writing skill data is normally distributed.

B. Data Analysis and Testing Hyphotheses

1. Data Analysis

Before the data is analyzed, the linearity and normality distribution of the data sets the two variables critical thiniking skill and argumentative writing skill are firstly tested. The linearity test is important to know whether the data is linear or not; while, the normality distribution is tested to know the data normality. Furthermore, the linearity and normality tests are crucial to decide whether parameter statistic or non-parameter statistic used in this study. In this study, the parameter statistic is used to calculate the data. Therefore, as the requirements in the parameter statistic in correlation research, the linearity and normality distributions of the data have to be examined first. The explanation of tests of linearity and normality distribution are presented as follow: a. Test of Linearity The linearity of critical thinking skill and argumentative writing skill data are analyzed by using SPSS software and presented using ANOVA Table. The result of the analysis is represented in the table below: Table 4.3 Data Linearity Analysis Table 4.3 above reveals the linearity distribution of the data of both critical thinking skill and argumentative writing skill. It results that the linearity data is in the significance of 0.00. It is lower than the level of significance 0.05 which the value is 4.05 0.00 4.05. Because the linearity value is lower than the level in significance of 0.05, it means that both of the data have linear distribution; therefore, parameter statistic is used in this study. ANOVA Table Sum of Squares df Mean Square F Sig. Argumentati ve Writing Skill Critical Thinking Skill Between Groups Combined 783.054 14 55.932 2.581 .026 Linearity 398.963 1 398.963 18.413 .000 Deviation from Linearity 384.091 13 29.545 1.364 .259 Within Groups 433.346 20 21.667 Total 1216.40 34