G. Trustworthiness of the Research
1. Normality Test
Before calculating the value of t-test using parametric statistics to measure hypothesis, the writer had to analyze the normality and homogeneity of the data.
The calculation of normality was needed to know whether the data has been normally distributed or not. The writer used SPSS v.22 by looking at the
Lilliefors formula to test the normality. In this formula, the data was transformed into the basic value. The maximum dispute T got from the calculation must be
in absolute value +. The result of normality can be seen by comparing the value of T
max
to T
table
. The criterion of hypothesis is:
H
1
: T
max
T
table
H : T
max
T
table
2. Homogeneity Test
Then, after getting the normality of the data, the next step was calculating the homogeneity of data. The purpose of this calculation was to see whether the
data in both classes were homogenous or not. The criteria of the test:
α = 0.05 H
: F
1- αn1-1
F F
12α n1-1n2-1
H
1
: F F
12α v1,v2
H. Technique of Data Analysis
To know the effectiveness of story mapping technique in reading comprehension, the writer used statistics analysis with the formula of t-test to
determine the final calculation. It is to measure the significance of the mean post-
test scores of the experimental class and control class. The writer calculated the data by using t-test formula. The formula of t-test as follows:
14
The process of t-test is as follow:
15
1. Determining mean of variable X Experimental Class, with formula:
2. Determining mean of variable Y Control Class, with formula:
3. Determining standard of deviation of variable X, with formula:
√
4. Determining standard of deviation of variable Y, with formula:
√
5. Determining standard error of mean variable X, with formula:
√
6. Determining standard error of mean variable Y, with formula:
√
14
Anas Sudijono, Pengantar Statistik Pendidikan, Jakarta: PT. Raja Grafindo Persada, 2008, p. 324.
15
Ibid., p. 325 —326.
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