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4.1.1.3 Histogram
Figure 4.3 The Histogram of Frequency of Pre test in the control group
Figure 4.4 The Histogram of Frequency of Pre test in the experimental
group
The figure of 4.5 and 4.6 show the histogram of the distribution of pre test score in the control group and experimental group. We may conclude that the
distribution of both data are normal, since the scores of both lowest and highest are low and the mean of the scores are in the middle which is in the range of score
43-46 and the peak score is 43 score. We stated that the distribution of the data is normal and tends to be stabil since the model is in a mount or bell shape and the
highest bar is in the middle.
4.1.2. Homegeneity Test
The results of the homogeneity test analysis can be seen in the figure below:
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4.1.2.1..Box-plots
Figure 4.5 The box-plot of homogeneity distribution of the pre test score in the
control group Figure
4.6 The
box-plot of
homogeneity distribution of the pre test score in the experimental group
The figure of 4.5 and 4.6 are the box-plots display which show the homogeneity of the data. The box area illustrates a visual description of the
variance. In both of the boxes in each group shows the homogeny of the data. In the control group pre test, the interquartile range is 6 and the median is about 43,
whereas since the most observation are on the high end of the scale, the distributionn is skewed left. A distribution that is skewed left has exactly the
opposite characteristics of one that is skewed right; the mean is typically less than the median, the tail of the distribution is longer on the left side than on the right
side and the median is closer to the third quartile that to the first quartile. The pretest score of the experimental group showed different distribution, since the
most observation tends to be in the middle of the scale, it is skewed symmetric. A symmetric distribution is one where the left and right hand sides of the
distribution are roughly equally balanced around the mean. The boxplot of the pretest experimental group shows a typical symmetric distribution. For
© Master Program in Linguistics, Diponegoro University www.eprints.undip.ac.id
symmetric distributions, the mean is approximately equal to the median. The tails of the distribution are the parts to the left and to the right, away from the
mean. The tail is the part where the counts in the histogram become smaller. For a symmetric distribution, the left and right tails are equally balanced, meaning that
they have about the same length. Another property of a symmetric distribution is that its median second quartile lies in the middle of its first and third quartiles.
The interquartile range of the experimental group pre test score is 5 and the median is about 41.
4.1.3 Significant difference of the pre-test and post-test using paired sample t- test
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