CHAPTER IV RESULT OF THE INVESTIGATION
4.1 Significant Difference between two Means
In this chapter, I would like to determine the different effectiveness of treatment given to both groups, which was reflected on the means gathered. I
would apply the t-test formula to count the difference. The t-test formula is:
⎟ ⎟
⎠ ⎞
⎜ ⎜
⎝ ⎛
+ ⎟
⎟ ⎠
⎞ ⎜
⎜ ⎝
⎛ −
+ +
− =
∑ ∑
y x
y x
y x
N N
N N
y x
M M
t 1
1 2
2 2
M
x :
mean of the control group M
y :
mean of experimental group ∑x
2
: sum of the square of deviation of the control group ∑y
2 :
sum of the square of deviation of the experimental group N
x :
number of sample of the control group N
y :
number of sample of the experimental group Arikunto
2002:280 There are three steps in computing the statistical analysis. First is
calculating the means scores of the experimental group and the control group. Second is calculating the deviation of each group and finally applying the t-test
formula. For the first step, I tried to find the increase of the score in control group
between pre-test and post-test. 35
36
The table of the control group
Subject Pre-test X1
Post-test X2 Differences X
X
2
1 87 100 13 169
2 63 87 24 576
3 60 80 20 400
4 73 67 -6 36
5 83 97 14 196
6 83 80 -3 9
7 67 97 30 900
8 70 87 17 289
9 90 73 -17 289
10 87 90 3 9
11 57 67 10 100
12 90 87 -3 9
13 80 100 20 400
14 70 93 23 529
15 67 87 20 400
16 83 87 4 16
17 67 90 23 529
18 83 70 -7 49
19 67 77 7 49
20 77 83 0 21 70 97 20
400 22 83 90 7
49 23 73 93 20
400 24 60 77 17
289 25 60 70 10
100 26 87 97 10
100 27 87 93 6
36 28 77 93 16
256 29 87 67 -20
400 30 83 90 7
49 31 70 70 0
32 80 93 13 169
33 90 70 -20 400
34 80 83 3 9
35 77 90 13 169
Σ
2678 2972 294 7780
The Mean of the control group is: M
x
=
Nx x
∑
M
x
=
35 294
M
x
=8.4
37
Next, the increase of scores of the experimental group is calculated.
The table of the experimental group
Subject Pre-test Y1
Post-test Y2 DifferencesY
Y
2
1 80 77
-3 9 2 67
80 13 169 3 70
100 30 900 4 57
77 20 400 5 70
83 13 169 6 77
87 10 100 7 87
97 10 100 8 80
100 20 400 9 63
90 27 729 10 83
97 14 196
11 57 93
36 1296 12 73
93 20 400
13 87 100 13 169
14 90 97
7 49 15 83
100 17 289 16 90
93 3 9
17 67 83
16 256 18 70
87 17 289
19 67 77
10 100 20 80
97 17 289
21 67 77
10 100 22 63
83 20 400
23 90 100 10 100
24 97 100
3 9 25 77
97 20 400
26 77 90
13 169 27 90
100 10 100 28 83
97 14 196
29 67 87
20 400 30 87
97 10 100
31 67 83
16 256 32 87
97 10 100
33 63 83
20 400 34 83
93 10 100
35 67 90
23 529 ∑ 2663 3182 519 9677
The mean of the experimental group is: M
y
=
Ny y
∑
M
y
=
35 519
M
y
=14. 8
38
After calculating the mean of the control group and experimental group, I calculated the deviation of the each group.
The computation of the deviation of the control group:
X
N X
X x
2 2
2
Σ −
Σ =
Σ
35 294
7780
2 2
− =
Σx
4 .
5310
2
= Σx
The deviation value of the control group is 5310.4
The computation of the deviation of the experimental group:
Y
N Y
Y y
2 2
2
Σ −
Σ =
Σ
35 519
9677
2 2
− =
Σy
97 .
1980
2
= Σy
The deviation of the experimental group is 1980.97 Finally, the t-test formula is applied
⎟ ⎟
⎠ ⎞
⎜ ⎜
⎝ ⎛
+ ⎟
⎟ ⎠
⎞ ⎜
⎜ ⎝
⎛ −
+ +
− =
∑ ∑
y x
y x
y x
N N
N N
y x
M M
t 1
1 2
2 2
⎟ ⎠
⎞ ⎜
⎝ ⎛
+ ⎟
⎠ ⎞
⎜ ⎝
⎛ −
+ +
− =
35 1
35 1
2 35
35 97
. 1980
4 .
5310 8
. 14
4 .
8 t
35 2
68 37
. 7291
4 .
6 ⎟
⎠ ⎞
⎜ ⎝
⎛ +
= t
742 .
2 4
. 6
+ =
t
589 .
2 =
t
39
4.2 Test of Significance
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