Interference Validity of the Test

itself. To sum up, a test is called reliable when it is tested on a similar group in similar condition, the result remains the same. Ary et al assumes that reliability concerns with how consistently a researcher measures whatever shehe measures 2002: 251. Moreover, they add that the reliability won’t concern about the meaning and interpretation of the scores, for they are more associated with the theory of validity. A measuring instrument can be reliable without being valid. Nevertheless, it cannot be valid unless it is first reliable. As an instance, a researcher decides to measure intelligence by determining the circumference of the head. The measurements may be reliable consistent from time to time, yet this method will not be considered valid if the circumference of the head does not correlate with any other criteria of intelligence nor is it predicted by any theory intelligence. Regarding this research, the instrument test that will be conducted might be reliable, yet it cannot be valid unless the instrument correlates with the theory and function of preposition for and to or contribute the functions of the prepositions for and to which have been applied in this research. In measuring the reliability of the test, the researcher uses one of the methods, which is the split-half technique Sprinthall et al, 1991: 35. The split-half technique of reliability is one kind of internal-consistency reliability, in which a test requires only a single administration of one form of a test Ary et al, 2002: 256. The test is split into two halves, and correlates the individual’s scores on the two halves; the first half the odd-numbered items was labelled X and the second half even-numbered items was labelled Y. Thus, the researcher uses The Pearson product-moment coefficient formula to determine the reliability of the test Sugiyono, 2010: 255. The formula can be seen as follows. Where ∑ xy = sum of the x times y scores ∑ x² = sum of the x squared scores ∑ y² = sum of the y squared scores r = Pearson Then, to indicate the reliability of the whole test, the Spearman-Brown Prophecy formula is needed. The formula can be seen as follows: r = 2r half-test 1 + r half-test Where r = The Spearman-Brown’s coefficient of reliability r half-test = The Pearson’s Correlation coefficient According to Ary et al, researchers must inquire into the validity and reliability of the scores derived from instruments test used in a study and must include this information in the researcher’s thesis as a repost. Nevertheless, if the data are not included with valid and reliable instruments, the readers might have little faith in the results gained or in the conclusions based on the results 2002: 242.

C. Theoretical Framework

Regarding the errors that contribute to the students’ difficulties in mastering the prepositions for and to that should be figured out, several theories are applied. Firstly, the theories of English prepositions for and to will be applied in order to measure the mastery level of the sixth semester students of English Letters Department in Sanata Dharma University in academic year 20152016. Thus, a test should be conducted to measure the accuracy of the sixth semester students at English Letters Department in mastering the prepositions of for and to. Secondly, there are also theories of Indonesian prepositions untuk, kepada, ke, buat and bagi and the language transfer that should be applied. These theories of Indonesian prepositions are used to indicate if the Indonesian language as the first language of the students will influence their second language learning. The last, the theories of error in language acquisition are used to indicate what seems to be the problems that will influence the students in mastering English prepositions for and to. 30

CHAPTER III METHODOLOGY

A. Object of the Study

The objects of this research were the sixth semester students of the 20152016 academic year, in English Letters Department of Sanata Dharma University. The sixth semester students were chosen to be the object of this research because the researcher intended to measure their ability in mastering the English prepositions for and to. Besides, the researcher also expected that the sixth semester students had already mastered the use of each preposition as part of English Grammar lesson that they had studied form first semester to fifth semester Structure I to Structure V.

B. Approach of the Study

The approach of the study applied in this research was the syntactic approach. According to Guralnik, syntax is the study of the arrangement of words as the elements in a sentence to show their relationship one another 1986: 1444. Moreover, syntax can also be defined as the rules, which specify how words may be combined with each other to produce grammatical and well-performed sentence Fromkin, 2000: 90. She also adds that syntax is made up of formal rules, which are formulated in a precise way with clearly defined properties. The syntactic approach was applied because this research dealt with the usage of prepositions for and to as the elements to form a correct sentence. PLAGIAT MERUPAKAN TINDAKAN TIDAK TERPUJI