39
7 UC-7 1 7 UC-27
1 8
UC-8 1 8 UC-28 1
9 UC-9 1 9 UC-29
1 10 UC-10
1 10
UC-30 1
11 UC-11 1
11 UC-31
12 UC-12 12
UC-32 13 UC-13
1 13
UC-33 1
14 UC-14 1
14 UC-34
1 15 UC-15
1 15
UC-35 1
16 UC-16 1
16 UC-36
1 17 UC-17
1 17
UC-37 1
18 UC-18 1
18 UC-38
1 19 UC-19
1 19
UC-39 1
20 UC-20 1
20 UC-40
total 18 Total
15
15 ,
20 15
18 =
− =
DP
From the computation above, the writer divided students in two groups. They were upper group was 18 and lower group was 15. Then the writer took it
into this formula with subtract 15 from 18 and divided with number of students in upper group, the results was 0.825.
According the criteria above, so item no. 1 has difficulty level is poor.
4.2 The Significant Difference of Pre Test Results
After getting scores of pre-test from experimental group and control group, the computation was made. First we got the results from two groups, like this:
Sources Experimental Control Total 2450 2370
N 39 39
x 62.82 60.77
Variants s
2
237 234
40
Standard deviation s
15.38 15.28
To make the analysis more reliable the writer analyzed by using t-test formula as stated in chapter III. The significant difference between the two groups
could be seen by using this formula:
Where: t :
t-test
1
x
: Mean of the experimental group
2
x
: Mean of the control group
1
n : Number of the sample experimental group
2
n : Number of the control group s : standard deviation
Before applying the t-test formula, s had to be found out first. The step was to get s:
2 39
39 60
. 233
1 39
57 .
236 1
39 −
+ −
+ −
= =
76 8877
74359 .
8989 +
=1.759 After getting s, we could find out value by t-test:
2 1
n 1
n 1
s x
x t
2 1
+ −
=
2 n
n 1
n 1
n s
2 1
2 2
2 2
1 1
− +
− +
− =
s s
2 1
n 1
n 1
s x
x t
2 1
+ −
=
41
183 .
5 39
1 39
1 759
. 1
77 .
60 82
. 62
= +
− =
From the computation above, the writer found out s firstly, the result was 1.759. Then put it into t-test formula with
1
x
Mean of the experimental group, the result was 62.82 from the computation before.
2
x
Mean of the control group, the result was 60.77.
1
n Number of the sample experimental group, it got from subtract 1 from number of students 40, so the result was 39.
2
n Number of the control group, it got from subtract 1 from number of students 40, so the result
was 39. Then applied it into t-test formula, the result was 5.183. In
α =5 with df = 78, so t
0.9578
39 + 39 – 2 = 1.992
With α =0, 05 with df =78, the critical value of t is 1.992. Therefore, the Ho
accepted area was the value between -1.992 and 1.992. The obtained t value from t-test is 5.183 and it was located in Ha refused area. Because t was located in
refused area Ha, so it could concluded there was significant of final condition between experimental group and control group. This was the experimental group
was better than control group.
Accepted area Ho
Refused area Ha
Ho
Refused area Ha
-1,992 1,992 5.183
42
4.3 The Significant Difference of Post Test Results
