Tabel 1.3 The Test Score of Student Pre-test in learning vocabulary without
Mnemonic Devices
Students Pre-Test
Post-Test D
D² X Y X-Y
X-Y² 1 68 93 -25 625
2 76 96 -20 400 3 70 97 -27 729
4 60 98 -38
1444 5 68 94 -26 676
6 74 82 -8 64 7 58 94 -36
1296 8 72 74 -2 4
9 70 92 -22 484 10 76 86 -10 100
11 70 98 -28 784 12 76 88 -12 144
13 68 92 -24 576 14 50 90 -40 1600
15 76 84 -8 64 N=15
∑X=1032 ∑Y=1358
∑D= -326 ∑D²=8990
B. ANALYSIS OF DATA
The last step in the procedure of pre-experiment is data analysis, in this case processing thee data. The data are the result of the pretest and post test and also their
difference. The writer compares the student pre test and post test score by using T-test or T-score is a statistic technique, which is used for testing the difference
signification of two mean from two distributions.
1
Before using the T-test formula, the writer has two seek the differences of mean variables by using formula as follows:
1
Anas Sujiono, Pengantar Statistik Pendidikan. Jakarat : PT. Manajemen Raja Grafindo Persada, hlm. 305-313
MD
SE MD
t =
= MD
Mean of differences, the average score from the differences gained score, Between
variable, which are calculated with the formula;
MY
SE
N D
MD
∑
= The total score between X and Y variable. D is gained with the
∑
= D
formula D = X-Y
N = Number of Class SD
D
= Standard deviation
D
= Standard the differences between score My variable, which is gained With the formula;
[ ]
2 2
N D
N D
SD
D
∑ ∑
− =
SE
MD
= The standard error from mean of differences which is gained with the Formula
1 −
= N
SD SE
D MD
Deviation of each variable. Based on the result calculation, the writer got the result of mean of X variable 68.8 and mean of variable Y is 90.53 , the median of
variable X is 70 and the median of variable Y is 92. Thus the writer found that standard deviation of variable X is 8.29 and variable Y is 9.51
Then the writer tried to find out standard deviation with the formula as follows:
[ ]
2 2
N D
N D
SD
D
∑ ∑
− =
[ ]
2
15 326
15 8990
− −
=
[ ]
73 ,
21 33
, 599
− −
=
2
19 ,
472 33
, 599
− =
14 ,
127 =
= 11,27 According to the data in table 3 above, the writer try to calculate the mean of
difference MD between variable X and Y with formula :
N D
MD
∑
=
15 326
− =
73 ,
21 −
= From mean of differences SE
MD
between variable X and Y
1 −
= N
SD SE
D MD
1 15
73 ,
11 −
=
14 73
, 11
=
74 ,
3 73
, 11
=
14 ,
3 =
The last procedure of calculation is determining the result of :
t
MD
SE MD
t =
14 ,
3 73
, 21
− =
92 ,
6 −
= df = N-1
= 15-1 = 14
According to the table above, df at significance level of 5 and 1 are:
5 = : = 6,92 2.04
t
t
t 1 =
: = 6,92 2.76 t
t
t It concludes that
t
observation
is higher than
t
table
t
t
t
C. INTERPRETATION OF DATA
