Test of hypothesis Inferential analysis
47
Mi and ideal standard deviation Sdi had to be found first. Mean was the average score of the students’ scores and it could be found by adding all the
students’ scores and divided them by all the number of the students. Meanwhile, standard deviation was a measurement of how the scores spread out. In this
categorization section, the researcher divided it into four main parts. They were the categorization of experimental group’s pre-test, the categorization of
experimental group’s post-test, the categorization of control group’s pre-test and the categorization of control group’s post-test. The result of descriptive statistic
can be seen in Table 10.
Table 10: Descriptive Statistic
N Minimum
Maximum Mean Std.Deviation
Pretest experimental Pretest control
Posttest experimental Posttest control
Valid N list wise 32
32 32
32 32
17.00 16.00
18.00 18.00
23.00 20.00
23.00 22.00
19.6563 18.5626
21.0625 19.6563
1.97744 1.34254
1.60518 1.12478
48
The Categorizing Formula Table 11: The categorizing formula and score categorization
Maximum score Minimum score
Mi Sdi
= 4 x 6 = 24 = 4 x 1 = 4
= 60100 x 24 = 14.4 = 25100 x 14.4 = 3.6
Good Average
Low : X ≥ Mi + Sdi
: Mi – Sdi ≤ X Mi + Sdi
: X Mi – Sdi
Category Good
Average Low
Score
: X ≥ 18 : 10.8 ≤ X 18
: X 10.8
From the table above, it could be concluded that ideal mean Mi was 14.4 and ideal standard deviation Sdi was 3.6. The categorization writing score based
on Anderson 2003:92.
The student’s writing ability score X was categorized as “GOOD” if it was more than and equals to 18. When the score was between 18
until and equaled to 10.8, the student’s writing ability was “AVERAGE”, and if the score was under 18, then the student’s writing ability was “LOW”.