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To know how extend do the improving students ’ English vocabulary
mastery by using visual Clustering, the writer used the percentage scale as the table below.
Table 3.1 Score Conversion Table
Score Qualification
75 —100
Very Good 65
—74 Good
55 —64
Fairly 45
—54 Poor
35 —44
Failed
J. Criteria of the Action Success
Classroom action research CAR is able to be called successful if it can
fulfill the criteria which have been determined, and fail if it cannot fulfill the criteria which have been determined.
Based on The criterion of minimum completeness KKM, when there is 75 of students achieve any improvement; gaining score 70 seventy of
vocabulary test started from the pre-test until the second post-test in cycle two, it means that this research could be called success. Then the next action would be
stopped, but if this condition has not been reached yet, the alternative action would be done in the next cycle.
K. The Trustworthiness of Study
In trustworthiness, the researcher will discuss about data collection in every observation from performing action research cycles are analyzed
descriptively by using percentage to see tendency that happened in learning activity.
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In analyzed the test item, the researcher uses to ways to know the trustworthiness of the data follow:
1. Discrimination Power The analysis of discriminating power test items is to know the
performance of the test through distinguishing students who have high achievement and low achievement. Discriminating power provides more detailed
analysis of the test items than the item difficulty, because it shows how the top score and lower score performed on each item.
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The computing of discriminating power uses the formula following:
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D = U-L N
In which, D
: The index of discriminating power U
: The number of pupils in upper group who answered the item correctly
L : The number of pupils group who answered item
Correctly N
: Number of pupils in each group Next, the discriminating power scale uses:
Table 3.2 The classification of Discriminating Power
DL REMARKS
0.6- 10 Very Good
0.4-0.6 Good
0.1-0.3 Ok
-1-0.0 Bad
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Kathleen M. Bailey, Learning about Language Assessment: Dillemas, Decissions, and Direction London:Heinle Heinle Publisher, 1998, p. 135.
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Tambunan Willmar, Evaluation of Students Achievement, Jakarta:Depdiknas, 1998, p. 139.
