Post-test Score Gained Score
17. 6
-2 2
-3 4
9 18.
6 8
2 7
4 49
19. 1
-4 -3
-5 9
25 20.
1 -4
-3 -5
9 25
21. 6
6 2
5 4
25 22.
-5 6
-9 5
81 25
23. -3
6 -7
5 49
25 24.
4 -8
-9 81
25. 4
-1 1
26. 2
-4 -6
-5 36
25 27.
13 9
-1 81
1 28.
10 6
-1 36
1 29.
14 10
-1 100
1 30.
-1 -3
-5 -4
25 16
Total 124
26 646
404
Mean 4.13333333
0.866666667 21.53333333
13.46666667
X = Gained Score of Experimental Class Y = Gained Score of Control Group
MX = Mean Score of Gained Scores of Experimental Class MY = Mean Score of Gained Scores of Control Group
According to the data in the table above, the result of the students’ pre
-test and post-test further in each class is calculated by using t-test in some steps as
follows: 1. Determining mean of variable X, with formula as follows:
Mx = x
N Mx =
124 30
Mx = .
2. Determining mean of variable Y, with formula as follows: My =
y N
My = 26
30
My = .
3. Determining standard of deviation score of variable X, with formula as follows:
SDx = x²
N
SDx = 646
30 SDx = 21.5
SDx = .
4. Determining standard of deviation score of variable Y, with formula as follows:
SD = y
N
SD = 404
30 SD =
13.4 SD = .
5. Determining standard error of mean of variable X, with formula as follows:
SE x = SDx
N 1
SE x = 4.63
30 1
SE x = 4.63
29 SE x =
4.63 5,38
SE x = . 6. Determining standard error of mean of variable Y, with formula as follows:
SE =
SD N
1 SE
= 3.66
30 1
SE =
3.66 29
SE =
3.66 5,38
SE = .
7. Determining standard error of different mean of variable X and variable Y, with formula as follows:
SE x SE
у
= SE x² + SE
у
² SE x
SE
у
= 0.86 + 0.68²
SE x SE
у
= 0.73 + 0.46
SE x SE
у
= 1.19
SE x SE
у
= . 8. Determining, to with formula as follows:
t = M
M SEᴍ
SEᴍ
t =
. .
.
t =
. .
t
= 9. Determining with degree of freedom df in significant level of 5 and 1
with formula as follows: Df = N + N
–
2
Df = 30 + 30
–
2 Df = 60
–
2 Df = 58
The value of df degree of freedom is 58. The value of 70 in the table “t”
score at significant level of 5 = 2.00 10. The comparison between t-observation and t-table:
2.00 3