was used to measure students‘ mastery in simple present tense after being
implemented with single slot substitution drills in cycle 1 and cycle 2. Finishing all the activities, I distributed questionnaire to the students to collect information
about their responses related to teaching and learning activities in improving simple present tense.
3.5 Try Out
Before the test was used to collect data, it was tried out to 34 students of one class from 6 classes of the first year students. I chose one class randomly from those
classes. The goal of conducting the try out test was to measure the validity and reliability
of the test. The test sheet could be seen in appendix 14
3.5.1 Validity
Groudlund cited by Brown 2004: 22 states that validity is the extent to which inferences made from assessment results are appropriate, meaningful, and useful
in terms of the purpose of the assessment. In addition, Heaton 1975: 159 says that validity is the extent to which it measures what it is supposed to measure and
nothing else. I used Pearson Product Moment Formula to calculate the validity of the test items.
The formula is:
r
xy
=
N ∑XY − ∑X ∑Y
{N∑X
2
− ∑X
2
}{N ∑Y
2
–∑Y
2
}
r
xy
= validity of each item N
= the number of students participates in the test ∑XY = the sum of multiple of score from each student with the total score in
each item ∑X = the sum of score in each item
∑X
2
= the sum of the square score in each item ∑Y = the sum of score from each student
∑Y
2
= the sum of the square score from each student The result is consulted with r product moment, r
xy
˃ r
table
is valid.
3.5.2 Reliability
Reliability is meant the stability of test scores Harris 1969: 14. To measure the reliability the writer used the KR-20 formula:
r
11
=
k k
−1 V
t
− ∑pq V
t
In which: r
11
= instrument reliability
k = the number of items in the test
V
t
= the total variance p
= the proportion of students passing a given item q
= the proportion of students that did not pass a given item ∑pq = the sum of p times q
3.5.3 Difficulty level
The index of difficulty or the facility value of an item simply shows how easy or difficult the particular item proved in the test Heaton 1975: 178. An item in
considered to have a good difficulty level if it is not too easy or too difficult for the students, so they can answer the items.
After getting the result of the try out, I classified and selected the item by using the formula:
FV= R
N In which:
FV = difficulty level
R = the number of students who answered the item correctly
N = number of students taking the test
Heaton 1975: 178
Criteria
Heaton 1975: 179 Difficulty Level
Criteria 0,00FV0,30
0,30FV0,70 0,70FV1,00
Difficult Medium
Easy
3.5.4 Discriminating Power
