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the right mechanics, I also taught them when they should use full stop, colon, semicolon, etc.
From the chart and the analysis, it could be seen that there is an improvement among each aspect. The treatment had influenced the writing ability of the
experimental group. Their writing ability improved after the treatment was given.
4.2.2 The Computation of the t-Test
I did the t-test to know the effectiveness of the treatment which was given to the students of the experimental group and the control group and the significant
difference between both groups. The first step before doing the t-test was calculating the average scores of the experimental and the control groups’ pretest
and the posttest scores. Besides calculating the average scores, I should complete three assumptions of the t-test before calculating the t-test.
4.2.2.1 The Experimental Group
After conducting the research in the experimental group, I calculated the average scores of the pretest and the posttest based on the research result.
4.2.2.1.1 The Average Score of the Pretest Scores
The pretest was conducted at the beginning of the research. It was done on May 2, 2011. There were 37 students who took the pretest. The purpose of giving the
pretest to the students of the experimental group was to check the students’ achievement in writing a narrative text before teaching writing narrative texts
using video clips as media in the treatment. In order to know the students’ achievement in detail, the following formula
was used to find out the average of the students’ pretest score:
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Where, X
1
= the mean the average score of the pretest scores of the experimental group students
ΣX
1
= the total of the experimental group students’ pretest scores N
X1
= the total of the experimental group students The computation of the mean the average score of the pretest scores of the
experimental group students was:
4.2.2.1.2 The Average Score of the Posttest Scores
On May 18, 2011, I gave the posttest to the students of the experimental group. The posttest was conducted at the end of the research. 37 students took the
posttest. The purpose of giving the posttest to the students of the experimental group was to check the students’ achievement in writing a narrative text after
teaching writing narrative text using video clips as media in the treatment. The following formula was used to find out the average of the students’
posttest score:
Where, X
2
= the mean the average score of the posttest scores of the experimental group students
ΣX
2
= the total of the experimental group students’ posttest scores N
X2
= the total of the experimental group students The computation of the mean the average score of the posttest score of the
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experimental group students was:
4.2.2.2 The Control Group
Besides conducting the research in the experimental group, I also conducted the research in the control group. I, then, also calculated the average scores of the
pretest and the posttest of the control group based on the research result. 4.2.2.2.1
The Average Score of the Pretest Scores Like the experimental group, I also gave the pretest for the students of the
control group. The pretest was conducted at the beginning of the research. It was done on May 2, 2011. There were 37 students who took the pretest. The purpose
of giving the pretest to the students of the control group was to check the students’ achievement in writing a narrative text before teaching writing narrative texts
using series of pictures as media in the treatment. The following formula was used to find out the average of the control group
students’ pretest score:
Where, Y
1
= the mean the average score of the pretest scores of the control group students
ΣY
1
= the total of the control group students’ pretest scores N
Y1
= the total of the control group students The computation of the mean the average score of the pretest score of the
control group students was:
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4.2.2.2.2 The Average Score of the Posttest Scores
On May 20, 2011, I gave the posttest to the students of the control group. The posttest was conducted at the end of the research. 37 students took the
posttest. The purpose of giving the posttest to the students of the control group was to check the students’ achievement in writing a narrative text after teaching
writing narrative texts using series of pictures as media in the treatment. In order to know the students’ achievement in detail, the following formula
was used to find out the average of the students’ posttest score:
Where, Y
2
= the mean the average score of the posttest scores of the control group students
ΣY
2
= the total of the control group students’ posttest scores N
Y2
= the total of the control group students The computation of the mean the average score of the posttest score of the
control group students was:
4.2.2.3 The Result of the t-Test
