Validity Instrument Technique of Data Collection
ΣX
2
= the squares of the sum of reading achievement scores ΣY
2
= the squares of the sum of Verbal – Linguistic Intelligence score
ΣXY = the sum multiple of reading achievement scores and VLI score Then, the contribution of the independent variable x towards the
dependent variable y is investigated through the determination coefficient r
2
as follows:
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R = r
2
x 100 R = value of determinant coefficient
r
2
= value of the squared correlation coefficient Moreover, after getting the r score, the significance between two
variables will be tested to know the correlation between variable X and variable Y. The formula of the significance test is:
8
t
count
=
�√�− √ −�
2
t
o
= t value r = value of correlation coefficient
n = number of sample
The last is to interpret the index scores of rcorrelation, product moment r
xy
usually used the interpretation such as bellow.
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Table 3.5 The Interpretation of Pearson Correlation
The score of “r” product moment r
xy
Interpretation
0.00 —0.19
There is a relationship between X and Y, but the correlation is very weak or little so it is ignored
or it is considered no correlation in this rating.
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Budi Susetyo, StatistikauntukAnalisis Data Penelitian, Bandung: PT RefikaAditama, 2010, p. 122.
8
Sugiyono, MetodePenelitianKuantitatif, Kualitatifdan R D, Bandung: Alfabeta, 2013, p. 187.
9
Jonathan Sarwono, Op. cit., p. 150.
The score of “r” product moment r
xy
Interpretation
0.20 —0.39
There is a relationship between X and Y, but it is weak or little.
0.40 —0.59
There is a relationship between X and Y. The value is medium.
0.60 —0.79
There is high relationshipbetween X and Y. 0.80
—1.00 There is a very high relationship between X and
Y.