Scope of Research Review of The Literature

45 Factor potential sources of error in measurement: a. Characteristic of the individual that influence the test score, such as intelligence, social desirability, and education b. Short term or transient personal factors, such as health, emotions, fatigue c. Situational factors, such as the presence of other people, noise, and distraction d. Sampling of item included in the scale: addition, deletion, or changes in the scale items e. Lack of clarity of the scale, including the instruction or the items themselves f. Mechanical factors, such as poor printing, overcrowding of items in the questionnaire, and poor design g. Administration of the scale, such as differences among interviewers h. Analysis factor, such as differences in scoring and statistical analysis Next the data obtained by use of a questionnaire, to which his analysis results will be presented in the form of a table. The results in the form of a table are analyzed based on variable Green Advertising and Consumer Engagement towards Green products as well as their impact on the purchasing decision Ades Mineral Water. 46

1. Validity and Reliability Test

a. Validity Test Validity is a measure that indicates the extent to which the measuring instrument was able to measure what it wants to quantified. Malholtra, 2003:269. Validity of the test done by comparing the value of r calculate with r table for the degree of freedom df = n – 2, in this case n is the number of samples. 30-2 = 28 and gained 0.05 alpha r table = 0.361. If r calculate is greater than r table then the grain question or otherwise valid indicators, if r calculate is lower than r table the grain of questions or indicators were declared invalid. b. Reliabity Test Reliability is the extend to which a scale produces consistent results if repated measurements are made on the last Malholtra 2003: 267. The value of variable reliability demonstrated by the Cronbach Alpha coefficient. A variable is said to be the Alpha Cronbach coefficient of Reliability when 0.60, when the variable is said to be 0.60 not reliability Malholtra 2003: 268.